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NC State Extension

WNC Orchard Insect Populations

Apples on a treeSeptember 14, 2020

The last full pest report was September 8, but traps will continue to be checked and the numbers updated until insect populations approach zero. Most pests except for brown marmorated stink bug are continuing to decline in number.

The full September 8 pest report, and all previous 2020 reports, can be seen by scrolling down this page.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Aug 31 Sep 7 Sep 14
Codling moth  0.1 0.0 0.1
Oriental fruit moth 4.3 2.6 4.4
Tufted apple bud moth 0.5 0.0 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 7.0 2.0 1.3
Brown marmorated stink bug (commercial) 3.7 7.3 4.3
Brown marmorated stink bug (unsprayed) 23.5 31.8 32.3
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 27.0 13.0 12.0
Peachtree borer 18.0 14.0 22.0
Lesser peachtree borer 38.0 33.0 29.0
San Jose scale 225.0 35.0 7.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Aug 31 Sep 7 Sep 14
Codling moth (Biofix 4/20) 2405 DD 2567 DD 2713 DD
Oriental fruit moth (Biofix 3/30) 3223 DD 3417 DD 3598 DD
Tufted apple bud moth (Biofix 4/27) 2965 DD 3159 DD 3340 DD

About degree-day models


2020 Pest Trends (click to enlarge)

Graph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trendsGraph of insect population trends


PREVIOUS REPORTS

Brown marmorated stink bugs on trapSeptember 8, 2020

With apple harvest well underway, and most pests other than the brown marmorated stink bug declining in numbers; this will be the last Pest Update for 2020.

First generation BMSB adults continue to emerge across the region, with about 90% of the population having emerged in Lincoln County, but only about 25% emergence complete in Haywood County (see Fig. 1 below). Estimated emergence in Henderson and Wilkes County is 45 and 62% complete, respectively. Pheromone trap captures continue to increase in Henderson County (see Fig. 2 below). With first generation adult emergence continuing for the next several weeks, expect trap captures to continue to increase. In 2018 and 2019, BMSB trap captures peaked about this time, but we are currently about 200 DD behind where we were at this time in previous years.

Figure 1: Percent emergence of brown marmorated stink bug in 2020. Figure 2: Brown marmorated stink bug trap captures in 2020 versus 2019 and 2018

It should be noted that BMSB pheromone trap captures are considerably lower in commercial apple orchards compared to non-orchard sites or orchards at the research station. Mean trap captures last week averaged about 5 and 32 per trap in commercial orchards and other sites, respectively. Nonetheless, with adult activity expected to continue for the next month, protection of highly susceptible cultivars (i.e., Granny Smith, Pink Lady) should be considered.

The only two other insect pests of potential concern are the oriental fruit moth and apple maggot, both of which exhibited declining trap captures during the past week. It is not typical for these pests to develop for the first time this late in the season, so the threat of damage should be considered very low for the remainder of the season.

While this is the last written report of the season, insect population tables and graphs will continue to be updated through the end of the month. Also, if something unexpected occurs, we will send a pest alert update.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Aug 24 Aug 31 Sep 7
Codling moth  0.0 0.1 0.0
Oriental fruit moth 6.7 4.3 2.6
Tufted apple bud moth 5.0 0.5 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 2.0 0.0 0.0
Apple maggot (abandoned and research orchards) 1.7 7.0 2.3
Brown marmorated stink bug (commercial) 2.4 3.7 7.3
Brown marmorated stink bug (unsprayed) 11.3 23.5 31.8
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 20.0 27.0 13.0
Peachtree borer 30.0 18.0 14.0
Lesser peachtree borer 40.0 38.0 33.0
San Jose scale 260.0 225.0 35.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Aug 24 Aug 31 Sep 7
Codling moth (Biofix 4/20) 2216 DD 2405 DD 2567 DD
Oriental fruit moth (Biofix 3/30) 2994 DD 3223 DD 3417 DD
Tufted apple bud moth (Biofix 4/27) 2736 DD 2965 DD 3159 DD

About degree-day models


Apple maggot trapSeptember 1, 2020

During the past week both brown marmorated stink bug and apple maggot populations increased in number.

Brown marmorated stink bug

BMSB pheromone trap captures in Henderson County increased considerably during the past week, as noted below in the figure that compares trap captures during the past three years. This trend of increasing BMSB trap captures is expected to continue in higher elevation locations (Haywood, Henderson and Wilkes Counties) where less than 50% of first generation adults have emerged to date (see the updated emergence figure below). In lower elevations such as Lincoln County, over 80% of first generation adults have emerged, so it is less likely that populations will rise significantly in those locations. The bottom line is that in these higher elevation orchards, late-maturing fruit will continue to be susceptible to damage for the rest of September.

BMSB trap capture charts

Apple Maggot

A significant increase in captures of apple maggot flies was finally observed this past week in our abandoned orchard site. Blocks adjacent to non-managed orchards that also have a good fruit load are likely to be most susceptible to infestation. Fortunately insecticides applied for BMSB will also control apple maggot.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Aug 17 Aug 24 Aug 31
Codling moth  0.5 0.0 0.1
Oriental fruit moth 4.3 6.7 4.3
Tufted apple bud moth 5.0 5.0 0.5
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 2.0 0.0
Apple maggot (abandoned and research orchards) 1.0 1.7 7.0
Brown marmorated stink bug (commercial) 3.1 2.4 3.7
Brown marmorated stink bug (unsprayed) 7.0 11.3 23.5
Spotted tentiform leafminer 2.0 0.0 0.0
Dogwood borer 17.0 20.0 27.0
Peachtree borer 18.0 30.0 18.0
Lesser peachtree borer 13.0 40.0 38.0
San Jose scale 117.5 260.0 225.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Aug 17 Aug 24 Aug 31
Codling moth (Biofix 4/20) 2095 DD 2216 DD 2405 DD
Oriental fruit moth (Biofix 3/30) 2843 DD 2994 DD 3223 DD
Tufted apple bud moth (Biofix 4/27) 2585 DD 2736 DD 2965 DD

About degree-day models


Apple Field Lab signAugust 25, 2020

In keeping with the theme of the past several weeks, insects of greatest concern at this time are brown marmorated stink bug (BMSB) and oriental fruit moth (OFM).

Emergence of first generation BMSB adults continues throughout the region. Based on model predictions, emergence is just beginning in higher elevations such as Haywood County, and is almost 75% complete in lower elevations such as Lincoln/Cleveland County.

Chart showing projected brown marmorated stink bug emergence in coming weeks

Brown marmorated stink bug

Based on pheromone trap captures to date, BMSB populations this year appear to be lower than last year at this time. This is illustrated in the figure below, which shows average BMSB pheromone trap captures in the same six locations over the past 3 years. While it is a little early to make predictions on the size of this year’s population, population densities appear to be similar to 2018 as opposed to 2019. We will continue to provide updates on populations over the coming weeks.

Chart showing brown marmorated stink bug trap captures over the last three years

Oriental fruit moth

As is typical for this time of the year, OFM pheromone trap captures have continued to increase in several locations. Where pyrethroids are being applied for BMSB, OFM should not be a problem, because these insecticides are quite effective against this pest. Where BMSB populations are low and insecticidal control is not warranted, it would be wise to keep an eye on OFM. Where mating disruption has been used, it is highly unlikely that OFM populations are problematic.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Aug 10 Aug 17 Aug 24
Codling moth  0.6 0.5 0.0
Oriental fruit moth 3.6 4.3 6.7
Tufted apple bud moth 5.5 5.0 5.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 2.0
Apple maggot (abandoned and research orchards) 1.7 1.0 1.7
Brown marmorated stink bug (commercial) 3.2 3.1 2.4
Brown marmorated stink bug (unsprayed) 2.8 7.0 11.3
Spotted tentiform leafminer 0.0 2.0 0.0
Dogwood borer 7.0 17.0 20.0
Peachtree borer 29.0 18.0 30.0
Lesser peachtree borer 22.0 13.0 40.0
San Jose scale 17.5 117.5 260.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Aug 10 Aug 17 Aug 24
Codling moth (Biofix 4/20) 1917 DD 2095 DD 2216 DD
Oriental fruit moth (Biofix 3/30) 2625 DD 2843 DD 2994 DD
Tufted apple bud moth (Biofix 4/27) 2367 DD 2585 DD 2736 DD

About degree-day models


apple picking ladders and bucketsAugust 18, 2020

Brown marmorated stink bug continues to be the primary insect of concern, and will be through September.

Brown Marmorated Stink Bug

First generation brown marmorated stink bug (BMSB) adults continue to emerge throughout most of the region. However, temperatures cooler than normal have delayed emergence compared to previous years. Based on our degree-day model (see below) first generation adult emergence has not yet begun in Haywood County, and is not predicted to begin until next week. In Henderson County, emergence is still in the early stages, with only about 12% of emergence complete, while in Wilkes and Lincoln Counties approximately 33% and 63% of adults have emerged, respectively.

It is important to remember that this model only predicts the time of adult emergence, not population intensity. While pheromone traps are the easiest method to determine population density, a threshold level is still in the preliminary stages. We do know, however, that we have not observed damage when cumulative trap captures remain below 5 adults per trap.

Chart showing brown marmorated stink bug emergence at various locations

Other Insect Pests

Except for those few orchards that have recently observed high codling moth or oriental fruit moth populations, these two insects should be of little concern the remainder of the year. Two generations of codling moth have been completed in all areas, and significant numbers of third-generation moths are rare unless second generation populations were also high. While OFM populations can often increase in August and early September, widespread use of pyrethroids for BMSB will also control OFM.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Aug 3 Aug 10 Aug 17
Codling moth  0.7 0.6 0.5
Oriental fruit moth 4.2 3.6 4.3
Tufted apple bud moth 0.0 5.5 5.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 1.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.7 1.7 1.0
Brown marmorated stink bug (commercial) 2.0 3.2 3.1
Brown marmorated stink bug (unsprayed) 3.3 2.8 7.0
Spotted tentiform leafminer 8.0 0.0 2.0
Dogwood borer 25.0 7.0 17.0
Peachtree borer 22.0 29.0 18.0
Lesser peachtree borer 22.0 22.0 13.0
San Jose scale 72.5 17.5 117.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Aug 3 Aug 10 Aug 17
Codling moth (Biofix 4/20) 1781 DD 1917 DD 2095 DD
Oriental fruit moth (Biofix 3/30) 2459 DD 2625 DD 2843 DD
Tufted apple bud moth (Biofix 4/27) 2201 DD 2367 DD 2585 DD

About degree-day models


Insect trap in apple orchardAugust 11, 2020

Brown marmorated stink bug adult emergence is becoming more widespread, while apple maggot and oriental fruit moth numbers increased in the past week.

Brown Marmorated Stink Bug

Emergence of first generation BMSB adults is approximately 50% complete in the Cleveland/Lincoln County area, while in Wilkes and Alexander Counties about 20% of the population has emerged (see emergence figure below). BMSB poses a threat to crops in these areas that have significant populations. Emergence is just beginning in Henderson County, so the threat of damage will increase significantly in the next week or so. In Haywood County and similar elevations, emergence is still at least a couple of weeks off.

Chart of brown marmorated stink bug emergence times

Codling Moth, Oriental Fruit Moth and Apple Maggot

Second generation codling moth is essentially complete throughout the area, and third generation populations are only expected in areas that have experienced problems up to this point. Both OFM and apple maggot trap captures increased over the past week, which is expected at this time of the year. Although numbers of these latter two pests were not particularly high at our monitoring sites, populations can vary considerably from orchard to orchard.

Below is a summary of the activity of various insecticides against the key pests of concern at this time, albeit those with a preharvest interval of no more than 21 days:

Insecticide range of activity against key insect pests of apple during August and September. (X = has activity)

Common name Brand name Pre-harvest interval (days)
BMSB OFM Codling moth Apple maggot
Pyrethroids
  Bifenthrin* Brigade, Bifenture 14 X X X
  Beta-cyfluthrin Tombstone 7 X X X
  Cyfluthrin Baythroid 7 X X X
  Fenpropathrin Danitol 14 X X X
  Gamma- cyhalothrin Proaxis 14 X X X
  Lambda-cyhalothrin Karate 21 X X X
  Zeta-cypermethrin Mustang Maxx 14 X X X
Neonicotinoids
  Chlothianidin Belay 3 X X
  Dinotefuran* Venom, Scorpion 3 X
Premixes
  Lambda-cyhalothrin + chlorantraniliprole Besiege 21 X X X X

*Bifenthrin and dinotefuran have Section 18 emergency exemption labels.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 27 Aug 3 Aug 10
Codling moth  0.7 0.7 0.6
Oriental fruit moth 4.8 4.2 3.6
Tufted apple bud moth 0.5 0.0 5.5
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 1.0 1.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.7 1.7
Brown marmorated stink bug (commercial) 1.7 2.0 3.2
Brown marmorated stink bug (unsprayed) 3.5 3.3 2.8
Spotted tentiform leafminer 16.0 8.0 0.0
Dogwood borer 6.0 25.0 7.0
Peachtree borer 31.0 22.0 29.0
Lesser peachtree borer 28.0 22.0 22.0
San Jose scale 265.0 72.5 17.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jul 27 Aug 3 Aug 10
Codling moth (Biofix 4/20) 1581 DD 1781 DD 1917 DD
Oriental fruit moth (Biofix 3/30) 2218 DD 2459 DD 2625 DD
Tufted apple bud moth (Biofix 4/27) 1960 DD 2201 DD 2367 DD

About degree-day models


Brown marmorated stink bug trap in rainy, windy apple orchardAugust 4, 2020

As has been the trend in recent weeks, overall insect pest pressure is low, and as we enter August the primary concern will be brown marmorated stink bug.

Codling Moth and Oriental Fruit Moth

About 2400 degree days (DD) have accumulated since biofix in Lincoln and Cleveland County, which corresponds with the end of second generation egg hatch. In Henderson County, DD accumulations are almost 1900, which corresponds to almost 90% adult emergence and 65% egg hatch. Except for those few areas where populations have been high throughout the year, it is highly unlikely that problems will develop at this point. Relying on pheromone trap captures to monitor population activity is the best option.

OFM populations have been variable throughout the region. Specific control measures against OFM are not needed if pheromone trap captures remain below 10 moths per trap. Where pyrethroids will be sprayed for BMSB, that application will also control OFM. If BMSB is not an issue and a pyrethroid is not necessary, a sprayable OFM pheromone application is also very effective. Finally, in orchards using mating disruption, it is unlikely that additional control measures will be necessary.

Brown Marmorated Stink Bug

Currently BMSB is of greatest concern in lower elevation orchards (<1000 ft elevation). Adult numbers generally begin to increase quite rapidly between 10 and 20% emergence, or around 750 DD after biofix (see chart below). In Cleveland County, where almost 50% of adults have emerged, expect populations to be high in hotspots. In the Wilkes County area, emergence has just recently begun, so expect to see numbers increase over the next couple of weeks. Finally, emergence in Henderson County is not expected to begin until next week, and for almost two weeks in Haywood County.

Graph of forecasted emergence for brown marmorated stink bug.

Apple Maggot

Captures of apple maggot flies remain low at our abandoned orchard site. Last year captures were also somewhat late, not increasing in numbers until 19 August. While not all orchards are susceptible to apple maggot infestation, the later the emergence the greater the chance it will coincide with sprays for BMSB, which are also effective against apple maggot.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 20 Jul 27 Aug 3
Codling moth  1.0 0.7 0.7
Oriental fruit moth 2.9 4.8 4.2
Tufted apple bud moth 0.0 0.5 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 1.0 1.0
Lesser appleworm 1.0 0.0 0.0
Apple maggot (abandoned and research orchards) 1.0 0.0 0.7
Brown marmorated stink bug (commercial) 1.2 1.7 2.0
Brown marmorated stink bug (unsprayed) 4.3 3.5 3.3
Spotted tentiform leafminer 30.0 16.0 8.0
Dogwood borer 9.0 6.0 25.0
Peachtree borer 33.0 31.0 22.0
Lesser peachtree borer 33.0 28.0 22.0
San Jose scale 1172.5 265.0 72.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jul 20 Jul 27 Aug 3
Codling moth (Biofix 4/20) 1406 DD 1581 DD 1781 DD
Oriental fruit moth (Biofix 3/30) 2008 DD 2218 DD 2459 DD
Tufted apple bud moth (Biofix 4/27) 1750 DD 1960 DD 2201 DD

About degree-day models


July 28, 2020

Canada geese in apple orchardCodling moth pheromone trap captures remain low throughout the area, while oriental fruit moth captures have crept up in several locations during the past week. The only location where first generation BMSB adult emergence is underway remains in lower elevation (<1000 ft) sites, although emergence is predicted to begin next week in the Wilkes County area.

Codling Moth and Oriental Fruit Moth (OFM)

Codling moth DD accumulations range from 1630 in Henderson County (2nd generation egg hatch about 35% complete) to 2250 in the Cleveland/Lincoln County region (2nd generation egg hatch is >80% complete). This is an important time to monitor for codling moth in Henderson County and other areas of similar elevation (about 2000 ft), because if populations are to appear in potentially damaging numbers, now is the likely time that will happen.

During the past week or so, OFM pheromone trap captures have increased in several locations. Although trap captures have not been excessively high, an insecticide application should be considered when numbers exceed about 10 moths per trap. In areas where a pyrethroid application was recently made for BMSB, that should also control OFM.

Brown Marmorated Stink Bug

The updated model output for emergence of first generation BMSB predicts emergence occurring only in lower elevation orchards (<1000 ft), but emergence is predicted to begin in the Wilkes County region next week (see figure below). Emergence is considerably delayed at higher elevations such as Henderson and Haywood Counties, where adult emergence is still several weeks away.

chart showing predicted emergence of BMSB

Apple Maggot

We are entering that time when apple maggot flies often begin to emerge in abandoned orchards. We have not yet detected a significant emergence, suggesting that this year’s cooler weather is also delaying emergence of this pest.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 13 Jul 20 Jul 27
Codling moth  0.5 1.0 0.7
Oriental fruit moth 3.3 2.9 4.8
Tufted apple bud moth 0.0 0.0 0.5
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 1.0 0.0 1.0
Lesser appleworm 0.0 1.0 0.0
Apple maggot (abandoned and research orchards) 0.7 1.0 0.0
Brown marmorated stink bug (commercial) 1.1 1.2 1.7
Brown marmorated stink bug (unsprayed) 1.8 4.3 3.5
Spotted tentiform leafminer 15.0 30.0 16.0
Dogwood borer 28.0 9.0 6.0
Peachtree borer 21.0 33.0 31.0
Lesser peachtree borer 35.0 33.0 28.0
San Jose scale 785.0 1172.5 265.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jul 13 Jul 20 Jul 27
Codling moth (Biofix 4/20) 1246 DD 1406 DD 1581 DD
Oriental fruit moth (Biofix 3/30) 1818 DD 2008 DD 2218 DD
Tufted apple bud moth (Biofix 4/27) 1560 DD 1750 DD 1960 DD

About degree-day models


July 21, 2020

apple leaves

Apple leaves showing bronzing from European red mite feeding.

At lower elevations (<1000 ft), first generation brown mamorated stink bug is beginning to emerge, while at higher elevations second generation codling moth is of primary concern. San Jose scale infestations are beginning to appear on apples in trials at the research station in Mills River, so now would be a good time to scout orchards to determine if any adjustments in insecticides are needed.

Codling Moth & Oriental Fruit Moth

Degree-day (DD) accumulations in Henderson and Cleveland County are at about 1440 and 2000 DD, respectively. This suggests that now is an optimum time for an insecticide application in Henderson County (and similar elevations), while second generation flight is nearing completion in lower elevation orchards. The exception would be in lower elevation orchards with high populations of codling moth, which would be indicated by high pheromone trap captures or recent larval infestations in fruit. In those orchards using mating disruption for codling moth, as well as those non-disrupted orchards that have had very low trap captures season-long, it is unlikely that insecticides are necessary at this time for codling moth. However, pheromone trap captures should be the key measuring stick. Oriental fruit moth pheromone trap captures have continued to be low at monitoring locations.

Brown Marmorated Stink Bug

Emergence of first generation adults is beginning in Cleveland County and other locations of similar elevation (<1000 ft). To provide better clarity of BMSB emergence predictions for multiple locations, the model output is depicted in a different manner this week (see below). As of today (July 21), DD accumulations in Cleveland County are at 737, which the model predicts is equivalent to emergence of about 8% of the population. By next week that will have increased to almost 30%. Hence, now is an important time for managing this pest in lower elevations. Based on future weather forecasts, it will be at least a week before emergence begins in Wilkes County, and even longer in Henderson and Haywood Counties.

Chart of brown marmorated stink bug emergence predictions at different elevations

Other Pests of Potential Concern

Now is good time to scout those sections of orchards where San Jose scale has been a problem in recent years. SJS fruit infestations are now appearing in the non-treated controls of our insecticide trials on the research station. Hopefully early season treatments were effective in managing this pest in commercial orchards, but if not, detecting problems now and adjusting insecticide sprays will minimize expansion of infestations. European red mites continue to be detected across the region, but, in most instances, if populations have not developed by late July it is unlikely they will become a problem.

Finally, captures of apple maggot continue to be very low at our abandoned site; this insect typically begins to emerge in larger numbers in late July to early August.

[Update] Dinotefuran Section 18 Request for Pome and Stone Fruits Approved

See details..


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 6 Jul 13 Jul 20
Codling moth  0.6 0.5 1.0
Oriental fruit moth 4.4 3.3 2.9
Tufted apple bud moth 3.0 0.0 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 1.0 1.0 0.0
Lesser appleworm 0.0 0.0 1.0
Apple maggot (abandoned and research orchards) 0.3 0.7 1.0
Brown marmorated stink bug (commercial) 0.8 1.1 1.2
Brown marmorated stink bug (unsprayed) 2.8 1.8 4.3
Spotted tentiform leafminer 34.0 15.0 30.0
Dogwood borer 42.0 28.0 9.0
Peachtree borer 19.0 21.0 33.0
Lesser peachtree borer 42.0 35.0 33.0
San Jose scale 1895.0 785.0 1172.5

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jul 6 Jul 13 Jul 20
Codling moth (Biofix 4/20) 1088 DD 1246 DD 1406 DD
Oriental fruit moth (Biofix 3/30) 1626 DD 1818 DD 2008 DD
Tufted apple bud moth (Biofix 4/27) 1368 DD 1560 DD 1750 DD

About degree-day models


Brown marmorated stink bug nymphJuly 14, 2020

Overall direct insect pest populations remain relatively low throughout the region, while populations of key secondary pests such as European red mite and leafhoppers are becoming more prevalent. In lower elevations of the piedmont, first generation brown marmorated stink bug will begin emerging later this week.

Codling Moth

In lower elevations near Cleveland and Lincoln Counties, codling moth degree day accumulations average 1830 DD since biofix, which coincides with about 60% egg hatch of the second generation. If trap captures remain low and there is no evidence of damage, the potential for populations to flare up at this time are very low. In Henderson County at an elevation of about 2100 ft, cumulative DD since biofix are only about 1275. Emergence of second generation adults picks up between 1400-1450 DD, which is predicted to occur early next week. For those using mating disruption for codling moth and OFM, it is unlikely that insecticides are needed for this generation, although pheromone trap captures should be the determining factor.

Brown Marmorated Stink Bug

As shown in the figure below, first generation BMSB adult emergence is predicted to begin by the end of this week in the Cleveland/Lincoln County area (1,000 ft elevation). Emergence begins at about 700 DD (predicted in this area for July 18), and by July 21 predicted DD accumulations are 735, which coincides with emergence of about 7% of the population. Insecticide applications for BMSB (see below) should be considered next week in those areas with a history of BMB problems.

Emergence of first generation adults is still at least three weeks away in higher elevations (>2000 ft). Degree-day accumulations at the MHCREC in Henderson County (2080 ft) is only at 435 DD as of July 14, and is predicted to be 495 in a week.

Figure of brown marmorated stink bug development

Insecticides effective against BMSB include several neonicotinoids (Actara and Belay) and most pyrethroids (i.e., Brigade, Bifenture, Baythroid, Danitol, Warrior/Karate, Mustang Max, Tombstone). It should be noted that neither neonicotinoids or pyrethroids are recommended for codling moth, so in those orchards where both BMSB and codling moth are of concern, either a tank mix with one of the above materials plus an insecticide effective against codling moth, or the premixes Besiege (chlorantraniliprole + lambda-cyhalothrin) or Voliam Flexi (chlorantraniliprole + thiamethoxam). Where Altacor (chlorantraniliprole) was used for first generation codling moth control, the above-mentioned premixes should not be used.

While the approval of the Section 18 request for bifenthrin was in last week’s update, it should be noted that this year’s request for dinotefuran (Venom, Scorpion) on apples has not been approved by the EPA. [UPDATE: On July 21, we announced that the dinotefuran request was approved.]


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 29 Jul 6 Jul 13
Codling moth  0.7 0.6 0.5
Oriental fruit moth 1.0 4.4 3.3
Tufted apple bud moth 4.0 3.0 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 1.0 1.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.7 0.3 0.7
Brown marmorated stink bug (commercial) 1.5 0.8 1.1
Brown marmorated stink bug (unsprayed) 1.9 2.8 1.8
Spotted tentiform leafminer 31.0 34.0 15.0
Dogwood borer 14.0 42.0 28.0
Peachtree borer 9.0 19.0 21.0
Lesser peachtree borer 33.0 42.0 35.0
San Jose scale 190.0 1895.0 785.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jun 29 Jul 6 Jul 13
Codling moth (Biofix 4/20) 919 DD 1088 DD 1246 DD
Oriental fruit moth (Biofix 3/30) 1421 DD 1626 DD 1818 DD
Tufted apple bud moth (Biofix 4/27) 1163 DD 1368 DD 1560 DD

About degree-day models


Irrigation pond at Mountain Horticultural Crops Research Station orchardsJuly 7, 2020

For the most part insect activity is relatively low throughout the western region, including the piedmont and mountain production areas. With the exception of emergence of second generation codling moth adults in lower elevation orchards in the piedmont, and a slight uptick in oriental fruit moth captures (but overall very low), the biggest concerns at this time are key secondary pests such as European red mite, leafhoppers and aphids. Initial captures of apple maggot flies in an abandoned orchard were detected in the past week, but numbers are still very low and not of concern in commercial orchards. In addition to the codling moth update below, this week we are also beginning to provide updates on model predictions for emergence of first generation brown marmorated stink bug, which poses the greatest threat to apples.

Codling Moth

Second generation codling moth degree day (DD) accumulations in Lincoln and Cleveland Counties is about 1575 as of July 7. Hence, an insecticide active against this pest should be considered at this time if moths have been captured in pheromone traps. If pheromone traps are not being used, you should assume there is activity in your orchard.

In higher elevations such as Henderson County, DD accumulations average only about 1090, so we are still approximately two weeks away from anticipated emergence of the second generation. Insecticides for codling moth are not necessary at this time, except for those few problem orchards where pheromone trap captures remain high.

BMSB Model Predictions

After several years of brown marmorated stink bug developmental studies in eastern and western NC, we are now quite confident of a simple degree-day model to predict emergence of first generation (f1) adults. These f1 adults disperse from wooded habitats into crops in July or August (depending on location and year), and are typically the most damaging life stage to fruit and vegetable crops. This model uses April 4 as a biofix date, and the percentage emergence of the f1 adult population is depicted by the blue line in the graph below, which shows emergence beginning at about 700 DD (Celsius) and being completed by 1400 DD.

The black arrows in the graph indicate current DD accumulations (as of July 7) for two locations (Henderson County at an elevation of 2067 ft, and Cleveland County at an elevation of 875 ft). Red arrows are DD projections for July 14 based on temperature forecasts. Current DD accumulations in Cleveland County are 570 DD, and are projected to be 645 on July 14. Hence, emergence of adults in Cleveland County is not anticipated for another two weeks. In Henderson County, current DD accumulations are only 375, so adult emergence is a minimum of three weeks away. Over the next two months we will update DD accumulations for these locations.

Brown marmorated stink bug degree day accumulation chart

Section 18 Requests for Bifenthrin Approved for BMSB

The NCDA&CS request to the EPA for a Section 18 exemption for the use of bifenthrin for control of the brown marmorated stink bug on apples, peaches and nectarines was recently approved. FMC and UPL are supporting these requests, so bifenthrin products registered for this use are Brigade and Bifenture. Labels for both products must be in possession when applying products, and they can be downloaded here:

A section 18 request for dinotefuran (Venom, Scorpion) was also submitted along with the bifenthrin request, but the NCDA&CS has not yet heard back regarding that request, nor have other states that made requests. [UPDATE: On July 21, we announced that the dinotefuran request was approved.]


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 22 Jun 29 Jul 6
Codling moth  0.0 0.7 0.6
Oriental fruit moth 1.6 1.0 4.4
Tufted apple bud moth 2.0 4.0 3.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 2.0 0.0 1.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.7 0.3
Brown marmorated stink bug (commercial) 0.8 1.5 0.8
Brown marmorated stink bug (unsprayed) 1.5 1.9 2.8
Spotted tentiform leafminer 24.0 31.0 34.0
Dogwood borer 9.0 14.0 42.0
Peachtree borer 5.0 9.0 19.0
Lesser peachtree borer 41.0 33.0 42.0
San Jose scale 2.5 190.0 1895.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jun 22 Jun 29 Jul 6
Codling moth (Biofix 4/20) 778 DD 919 DD 1088 DD
Oriental fruit moth (Biofix 3/30) 1246 DD 1421 DD 1626 DD
Tufted apple bud moth (Biofix 4/27) 988 DD 1163 DD 1368 DD

About degree-day models


June 30, 2020

apples on treeThroughout most of the higher elevation orchards (≥2000 ft), we are still in that period of low potential for insect damage. Codling moth degree-day accumulations are only at about 940 as of June 30, indicating first generation flight is complete and second generation flight is still a few weeks off. Also, OFM populations remain low in most orchards. The most common insects are secondary pests such as aphids, leafhoppers and mites, all of which can be managed with curative insecticide/miticide applications. Monitoring for these pests over the next few weeks should be conducted to determine the need for insecticides.

In lower elevation orchards, such as Lincoln and Cleveland Counties and other locations ≤1000 ft, second generation codling moth flight is just beginning. Cumulative codling moth DDs in this area are about 1400 DD, and insecticides are recommended at about 1450 DD when populations are of moderate to high density. Where populations are low – no damage by the first generation and low pheromone trap captures (no more than 1 or 2 moths per week) – insecticide applications can be delayed to 1550-1600 DD, or not applied if trap captures remain very low.

In orchards using mating disruption for codling moth and OFM, insecticides targeting second generation are rarely needed, although pheromone trap monitoring should be used to verify the absence of moths.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 15 Jun 22 Jun 29
Codling moth  0.3 0.0 0.7
Oriental fruit moth 2.6 1.6 1.0
Tufted apple bud moth 23.0 2.0 4.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 14.0 2.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.0 0.7
Brown marmorated stink bug (commercial) 1.1 0.8 1.5
Brown marmorated stink bug (unsprayed) 4.3 1.5 1.9
Spotted tentiform leafminer 0.0 24.0 31.0
Dogwood borer 36.0 9.0 14.0
Peachtree borer 3.0 5.0 9.0
Lesser peachtree borer 54.0 41.0 33.0
San Jose scale 0.0 2.5 190.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jun 15 Jun 22 Jun 29
Codling moth (Biofix 4/20) 678 DD 778 DD 919 DD
Oriental fruit moth (Biofix 3/30) 1111 DD 1246 DD 1421 DD
Tufted apple bud moth (Biofix 4/27) 853 DD 988 DD 1163 DD

About degree-day models


June 23, 2020

aphidsWe are currently in a lull of direct pest activity throughout the western apple region. Codling moth degree-day (DD) accumulations have reached about 800 and 1250 in Henderson and Cleveland/Lincoln Counties, respectively. First generation adult emergence is essentially complete in orchards at elevations of ~2100 ft, and in lower elevations (<800 ft) second generation adult emergence is predicted to begin in about a week.

Tufted apple bud moth cumulative DDs are about 1,000, so there is still time to make an insecticide application for this pest if one has not been made in the past couple of weeks.

Second generation oriental fruit moth flight is also nearing completion, with low trap captures in orchards we’ve been monitoring.

Curative applications of insecticides/miticides for control of aphids, leafhoppers or European red mites is the main concern at this time. However, overall populations remain low in most orchards, so be sure to scout orchards for these pests to determine the need for an insecticide.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 8 Jun 15 Jun 22
Codling moth  0.4 0.3 0.0
Oriental fruit moth 1.1 2.6 1.6
Tufted apple bud moth 27.0 23.0 2.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 20.0 14.0 2.0
Lesser appleworm 8.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.0 0.0
Brown marmorated stink bug (commercial) 1.5 1.1 0.8
Brown marmorated stink bug (unsprayed) 5.0 4.3 1.5
Spotted tentiform leafminer 10.0 0.0 24.0
Dogwood borer 58.0 36.0 9.0
Peachtree borer 0.0 3.0 5.0
Lesser peachtree borer 68.0 54.0 41.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jun 8 Jun 15 Jun 22
Codling moth (Biofix 4/20) 541 DD 678 DD 778 DD
Oriental fruit moth (Biofix 3/30) 938 DD 1111 DD 1246 DD
Tufted apple bud moth (Biofix 4/27) 680 DD 853 DD 988 DD

About degree-day models


June 16, 2020

trap in orchardCodling Moth

Cumulative degree days (DD) for codling moth in Henderson County are about 690 as of today (June 16). This is indicative of about 90% emergence of overwintered adults and 50% egg hatch. While this insect is still a threat to injure apples, populations have been very low in most orchards. Where pheromone trap captures have been high, insecticide applications are still warranted. Off the mountain in Lincoln/Cleveland County, about 1050 DD have accumulated, which indicates that we are between generations.

Tufted Apple Bud Moth

TABM DD accumulations in Henderson County are about 865 from biofix as of June 16. Ideal timing for TABM control is between 800 and 1200 DD, although applications made slightly before this (700-750) often result in good control. If an insecticide effective against TABM has not been made within the past week, one should be made at the next application. In those orchards where codling moth remains a concern, Altacor, Verpedryn or Delegate (whichever AI is being used for first generation codling moth) will also provide excellent control of TABM. In orchards with low codling moth populations, Intrepid at 6 to 8 oz/acre is a good choice for TABM control. In those orchards using mating disruption for codling moth and OFM, remember that this pheromone does not affect TABM populations, so an insecticide is needed for TABM.

Oriental Fruit Moth

Second generation OFM flight is currently underway, but populations of this generation are typically very low due to insecticides applied at petal fall for the first generation, and overlap of this flight with TABM. Trap captures remained very low at our trapping sites during the past week.

Secondary Pests

Populations of aphids, leafhoppers and European red mite remain surprisingly low in both commercial orchards and in the non-treated controls of plots at the research station.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 1 Jun 8 Jun 15
Codling moth  0.5 0.4 0.3
Oriental fruit moth 0.4 1.1 2.6
Tufted apple bud moth 81.0 27.0 23.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 7.0 20.0 14.0
Lesser appleworm 7.0 8.0 0.0
Apple maggot (abandoned and research orchards) set 0.0 0.0
Brown marmorated stink bug (commercial) 0.6 1.5 1.1
Brown marmorated stink bug (unsprayed) 1.3 5.0 4.3
Spotted tentiform leafminer 0.0 10.0 0.0
Dogwood borer 37.0 58.0 36.0
Peachtree borer 0.0 0.0 3.0
Lesser peachtree borer 48.0 68.0 54.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jun 1 Jun 8 Jun 15
Codling moth (Biofix 4/20) 402 DD 541 DD 678 DD
Oriental fruit moth (Biofix 3/30) 765 DD 938 DD 1111 DD
Tufted apple bud moth (Biofix 4/27) 507 DD 680 DD 853 DD

About degree-day models


June 9, 2020

Apple orchard with mountain laurel on borderCodling Moth

At lower elevations, less than about 1200 ft, cumulative codling moth degree days (DD) now exceed 1000, indicating that the first generation is complete. Insecticides targeting codling moth are probably unnecessary until at least 1400 DD; the exception being in those orchards with high populations that are still capturing more than 5 moths per week in pheromone traps.

In Henderson County (2100 ft), codling moth degree-day accumulations are at about 560 DD, so this pest should still be considered a potential threat in this area. If pheromone trapping is not being conducted, it would be wise to assume a potentially damaging population exists in an orchard. Populations have been low this season, and it has been possible for many to minimize insecticide applications when using pheromone traps to verify low populations.

In orchards using mating disruption for codling moth and where insecticides for lepidopteran pests have probably not been necessary thus far, note that is now time for control of tufted apple bud moth (below), since codling moth/OFM mating disruption does not control TABM.

Tufted Apple Bud Moth

Tufted apple bud moth DD accumulations in Henderson County average about 710 as of today (June 9). However, degree days are accumulating quickly and 800 DD, optimum time for an insecticide targeting TABM, is expected to occur Saturday (June 13). Excellent control of TABM can be achieved with a single recommended insecticide applied anytime between now and the next two weeks. In those orchards where codling moth is also a concern, Altacor, Verpedryn, and Delegate are recommended. Where codling moth populations are low, Intrepid at 8 oz/acre will provide excellent TABM control, although it is not as efficacious against codling moth as the aforementioned products.

Aphids, Leafhoppers and Mites

Now is also a time when green apple aphid, potato leafhopper and European red mite populations traditionally appear in apples. While populations have been low thus far, these are secondary pests to keep an eye on when scouting orchards. There are a wide array of selective insecticides that control both aphids and leafhoppers, so check the Southeastern Apple Manual for those recommendations.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 26 Jun 1 Jun 8
Codling moth  0.1 0.5 0.4
Oriental fruit moth 0.2 0.4 1.1
Tufted apple bud moth 25.5 81.0 27.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 7.0 20.0
Lesser appleworm 0.0 7.0 8.0
Apple maggot (abandoned and research orchards) set 0.0
Brown marmorated stink bug (commercial) 0.8 0.6 1.5
Brown marmorated stink bug (unsprayed) 1.8 1.3 5.0
Spotted tentiform leafminer 0.0 0.0 10.0
Dogwood borer 14.0 37.0 58.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 16.0 48.0 68.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
May 26 Jun 1 Jun 8
Codling moth (Biofix 4/20) 299 DD 402 DD 541 DD
Oriental fruit moth (Biofix 3/30) 631 DD 765 DD 938 DD
Tufted apple bud moth (Biofix 4/27) 374 DD 507 DD 680 DD

About degree-day models


June 2, 2020

insect on underside of leafCodling Moth

Codling moth degree-day (DD) accumulations range from 420 in Henderson County to about 750 in the Lincoln/Cleveland County area. Henderson County, and locations of similar elevation (>2000 ft), are in the midst of first generation flight, and codling moth should be considered a potential concern for another two weeks. With that said, to date populations have been very low in Henderson County. In lower elevation orchards with an accumulation of 750 DD, we are approaching the end of first generation adult emergence (>90% emergence complete), and additional insecticide applications are most important where first generation populations have been high based on pheromone trap captures.

Tufted Apple Bud Moth

Tufted apple bud moth DD accumulations in Henderson County are about 525 as of June 2. Historically TABM populations are more important in Henderson County opposed to other production regions. Based on forecasts, the ideal timing for an insecticide will be in about 7 to 10 days, when DD accumulations will approach 800. A single application of an insecticide recommended for codling moth will provide season long control of TABM; these include the diamides (i.e., Altacor, Voliam Flexi, Exirel, Verdepryn) or Delegate. In addition, Intrepid also provides excellent season-long control of TABM. Because the diamides and Delegate are more effective against codling moth than Intrepid, the latter should only be used where codling moth is not a concern.

Secondary Pests

Aphids, leafhoppers and mites have been very low to nonexistent up to this point in time. However, with warmer and hopefully drier weather returning, these are pests to keep an eye out for in the coming weeks.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 18 May 26 Jun 1
Codling moth  0.5 0.1 0.5
Oriental fruit moth 0.5 0.2 0.4
Tufted apple bud moth 8.0 25.5 81.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 7.0
Lesser appleworm 0.0 0.0 7.0
Apple maggot (abandoned and research orchards) set
Brown marmorated stink bug (commercial) 0.6 0.8 0.6
Brown marmorated stink bug (unsprayed) 1.8 1.8 1.3
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 14.0 14.0 37.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 16.0 16.0 48.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
May 18 May 26 Jun 1
Codling moth (Biofix 4/20) 202 DD 299 DD 402 DD
Oriental fruit moth (Biofix 3/30) 496 DD 631 DD 765 DD
Tufted apple bud moth (Biofix 4/27) 238 DD 374 DD 507 DD

About degree-day models


May 27, 2020

Ragwort flowers beside apple orchardrdCodling moth remains the insect of greatest concern throughout the region, with degree-day accumulations since biofix ranging from about 325 in Henderson County to 630 in Lincoln County. In orchards not using mating disruption, an initial application is recommended between 250 and 350 DD. Codling moth can remain a threat until about 900 DD, although this can vary considerably depending on population pressure. As a reminder, if making multiple applications against the first generation, insecticides with the same mode of action should be made throughout this time. Wait until second generation codling moth emergences (about 1400 DD) to switch to an insecticide with a different mode of action.

In orchards using mating disruption, an insecticide is usually not recommended until the timing is ideal for tufted apple bud moth (see below).

In Henderson County, where tufted apple bud moth (TABM) is of greatest concern, we are approaching 400 DD. A single application of either Altacor, Delegate, Intrepid, or Verdepryn (same mode of action as Altacor) between 800-1200 DD after biofix will provide season-long control of TABM. The timing of this coincides with about 650 DD for codling moth, which allows for control of both pests.

Apple aphid and potato leafhopper populations have not been observed up to this point, but they should begin to appear over the next couple of weeks. If control of these insects is needed, options include Voliam Flexi (same active as Altacor plus Actara), or addition of a neonicotinoid with one of the above-mentioned insecticides for codling moth or TABM.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 12 May 18 May 26
Codling moth  0.4 0.5 0.1
Oriental fruit moth 0.3 0.5 0.2
Tufted apple bud moth 11.0 8.0 25.5
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 0.3 0.6 0.8
Brown marmorated stink bug (unsprayed) 0.1 1.8 1.8
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 1.0 14.0 24.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 20.0 16.0 32.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
May 12 May 18 May 26
Codling moth (Biofix 4/20) 135 DD 202 DD 299 DD
Oriental fruit moth (Biofix 3/30) 400 DD 496 DD 631 DD
Tufted apple bud moth (Biofix 4/27) 142 DD 238 DD 374 DD

About degree-day models


May 19, 2020

row in apple orchardCodling moth pheromone trap captures increased somewhat this week with the return of warmer temperatures, and as of May 19 degree day accumulations ranged from about 220 in Henderson County to 500 in Lincoln and Cleveland County. In orchards with moderate to high codling moth populations, the 250 DD threshold for initial insecticide applications is predicted to occur later this week in Henderson County and other locations with a similar elevation. In orchards with low populations, an insecticide application can be delayed until at least 350 DD, which is predicted to occur in the middle of next week (May 27). Finally, those orchards using mating disruption and where codling moth populations are very low, it is likely that an insecticide targeting lepidopterans can wait until the optimum timing for tufted apple bud moth, which is between 600 and 800 DD.

In lower-elevation orchards where at least one insecticide application has been applied for codling moth, this pest will remain a concern for another couple of weeks, and the need for continued sprays should be based on pheromone trap captures.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 4 May 12 May 18
Codling moth  1.6 0.4 0.5
Oriental fruit moth 1.5 0.3 0.5
Tufted apple bud moth 14.0 11.0 8.0
Redbanded leafroller 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 0.8 0.3 0.6
Brown marmorated stink bug (unsprayed) 0.3 0.1 1.8
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 1.0 14.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 51.0 20.0 16.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
May 4 May 12 May 18
Codling moth (Biofix 4/20) 90 DD 135 DD 202 DD
Oriental fruit moth (Biofix 3/30) 332 DD 400 DD 496 DD
Tufted apple bud moth (Biofix 4/27) 74 DD 142 DD 238 DD

About degree-day models


May 12, 2020

bud on apple Expect Codling Moth Activity to Pick Up with Return of Warmer Temperatures

The cool temperatures during the past week suppressed insect activity, as evidenced by the very low pheromone trap captures. However, activity will pick up later in the week with the return of warmer temperatures. The codling moth degree-day (DD) model predicts initial egg hatch to occur at about 250 DD after biofix, which is also the recommended timing of an initial insecticide application in orchards with moderate to high codling moth populations. In orchards with low populations, an application can be delayed until 350 DD. In Henderson County, 250 DD is not expected to occur until May 18. Off the mountain at lower elevations considerably more DD have accumulated. In the Lincoln and Cleveland County areas DD accumulations have reached about 400 DD, which is equivalent to about 10% egg hatch. In these areas, protection of the crops will be important later this week and into next week.

Time to Target San Jose Scale Crawlers

For those concerned about San Jose scale and wanting to target first generation crawlers, an insecticide application within the next two weeks should be considered. See last week’s update for more information.

Brown Marmorated Stink Bug

I have received several questions about the status of brown marmorated stink bug (BMSB), and in view of the current emergence of overwintering adults, now may be a good time to review its life cycle and potential for damage.

Overwintering Adult Emergence and Egg Laying:  The vast majority of overwintering BMSB adults emerge during April and May. While we are slightly behind the curve this year due to relatively cool temperatures, the return of warmer weather should put us on track to be completed by late May or early June. Overwintering adults reside largely in wooded habitats, feeding and laying eggs on wild hosts from mid-May through July. Egg laying can begin as early as mid-May in lower elevations (piedmont) to late May in mountain apple production regions (>2000 ft); peak oviposition occurs during the month of June. These wooded habitats are also where the vast majority of nymphal populations reside and complete development.

While occasionally a few adults may be found in apple orchards during June, apples are not a highly attractive host during this time. Slightly more attractive hosts are peaches and pears, where BMSB can be more easily found in June. In previous years, high pheromone trap captures of the overwintering generation have occurred in late May.

First Generation Adults:  When first generation nymphs in wooded areas develop to the adult stage, many of these adults disperse to crops, with a high preference for those plants bearing fruiting structures, including apples and many other crops (peaches, pears, corn, soybeans, etc.). It is this first generation of adults that present the greatest threat to apples. The timing of first generation adults varies from July in the piedmont to August in the mountains.

Predicting Adult Emergence:  We have recently completed a degree-day (DD) model that can be used to predict emergence of first generation adults. The model functions similar to that of the codling moth DD model. April 1 is used as biofix (date to begin accumulating DD) and lower and upper developmental threshold temperatures of 14.2°C and 35.6°C, respectively, are used to calculate DD. First generation adults begin to emerge at about 700 DD (°C), with 10% of adult emergence complete by 750 DD; the range of DD during for emergence of 10-90% emergence occurs is 740-1245 DD (°C). In 2019, 700 DD occurred on 3 July in Cleveland County and 31 July in Henderson County. Further east in Wayne County in the coastal plain region, 700 DD occurred on 8 June. The equivalent of 700 cumulative DD (°C) in Fahrenheit is 1400 DD (°F)

Pheromone Trap Threshold:  While we can now predict when first generation adults emerge, it should be recognized that not all locations have damaging populations of BMSB. Last year we conducted studies to assess a threshold of a cumulative capture of 4 BMSB adults per trap as a trigger for insecticide applications – weekly trap captures were added for each successive week. This threshold was deemed too low as it resulted in over spraying. These studies will be continued this year to try and narrow down an appropriate threshold level.

In the next few weeks we will begin reporting on BMSB DD accumulations and pheromone trap captures in the region.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 27 May 4 May 12
Codling moth  0.4 1.6 0.4
Oriental fruit moth 0.8 1.5 0.3
Tufted apple bud moth 1.0 14.0 11.0
Redbanded leafroller 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 0.0 0.8 0.3
Brown marmorated stink bug (unsprayed) 0.0 0.3 0.1
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer set 0.0 1.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 0.0 51.0 20.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Apr 27 May 4 May 12
Codling moth (Biofix 4/20) 34 DD 90 DD 135 DD
Oriental fruit moth (Biofix 3/30) 250 DD 332 DD 400 DD
Tufted apple bud moth (Biofix 4/27) Biofix 74 DD 142 DD

About degree-day models


May 5, 2020

moth on leafCooler Temperatures Expected to Suppress Codling Moth Activity

With the warmer temperatures during the past week, there was an increase in codling moth trap captures compared to recent weeks. However, with cooler temperatures moving into the region in the next couple of days, and expected to stick around for a week, insect activity will likely be greatly reduced. Codling moth degree day (DD) accumulations across the region range from about 100 at the Research Station in Henderson County to almost 350 in Lincoln County. The initial insecticide application for first generation codling moth is recommended at 250 DD, which is not expected for at least 10 to 14 days in Henderson County. Off the mountain in Lincoln County, most locations have probably applied at least one application for first generation codling moth. Further applications, if warranted, can likely be delayed during this cold period.

Time is Approaching for San Jose Scale Crawler Emergence

For those growers concerned about San Jose scale and who have not yet applied an insecticide for this pest, the optimum timing for targeting crawlers is mid-May in Henderson County (see graph below), and about a week earlier off the mountain in the piedmont. In lower elevations now is a good time to target crawlers, while in Henderson County a week or two from now would be optimal. Three insecticides, including Esteem, Courier and Movento, have all demonstrated excellent season-long control when applied to coincide with crawler emergence.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 20 Apr 27 May 4
Codling moth  0.1 0.4 1.6
Oriental fruit moth 0.1 0.8 1.5
Tufted apple bud moth 0.0 1.0 14.0
Redbanded leafroller 0.0 0.0
Obliquebanded leafroller set 0.0 0.0
Lesser appleworm set 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 0.1 0.0 0.8
Brown marmorated stink bug (unsprayed) 0.1 0.1 0.3
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer set 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 0.0 7.0 51.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Apr 20 Apr 27 May 4
Codling moth (Biofix 4/20) Biofix 34 DD 90 DD
Oriental fruit moth (Biofix 3/30) 185 DD 250 DD 332 DD
Tufted apple bud moth (Biofix 4/27) Biofix 74 DD

About degree-day models


April 28, 2020

Attention Turns to the Codling Moth

Apple orchardWith petal fall sprays complete, the next several weeks will be focused predominately on codling moth. Biofix varied widely between the piedmont and mountain regions this year, ranging from April 1 in Lincoln County to as recent as April 20 in Henderson County. Based on these dates, codling moth degree day accumulations range from approximately 275 (Lincoln County at 850 ft) to only about 70 (Henderson County at 2100 ft). The codling moth DD model recommends initial sprays for the first generation at 250 DD under moderate to high pressure. Under low pressure, initial applications can be delayed until about 350 DD. Based on current DD accumulations, sprays targeting the first generation should be made now in the piedmont region. In higher elevations, 250 DD is not expected for at least another 10 days.

Insecticide Resistance Management Practices

The two classes of insecticides recommended for codling moth remain the anthranilic diamides (MOA group 28, including Altacor, Exirel, and Verdepyrn) and spinosyns (MOA group 5, including Delegate). These two groups have been used for codling moth for >10 years, and remain the most effective options. One reason they remain so effective is because of good insecticide resistance management practices used by growers. This program consists of using different classes of insecticides against different generations. For instance, regardless of how many applications are required to control the first generation (usually from 1 to 3 sprays), all applications should be from the same class – either anthranilic diamide OR spinosyn. Whichever class was used against the first generation should NOT be used against the second generation in July; instead use an insecticide from the other class.

It is also important to remember that each of the three different insecticide products in the anthranilic diamide class have the same mode of action. Hence, it is all right to use more than one product during the same generation. Finally, for those using Voliam Flexi, this premix includes chlorantraniliprole, the same active ingredient as Altacor. So for codling moth resistance management practices it is also classified as an anthranilic diamide.

For those growers using mating disruption, insecticides for codling moth are usually not necessary against the first generation – although a codling moth-active product is recommended for leafrollers at third cover. For those that may be skipping the use of mating disruption after having used it for numerous years, populations will likely remain low, but pheromone trapping should be used to confirm low populations and the need for insecticide applications


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 14 Apr 20 Apr 27
Codling moth  0.0 0.1 0.4
Oriental fruit moth 9.4 0.1 0.8
Tufted apple bud moth 0.0 0.0 1.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller set 0.0
Lesser appleworm set 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 0.1 0.0
Brown marmorated stink bug (unsprayed) 1.0 0.1 0.1
Spotted tentiform leafminer 2.0 0.0 0.0
Dogwood borer set
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 1.0 0.0 7.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Apr 14 Apr 20 Apr 27
Codling moth (Biofix 4/20) Biofix 34 DD
Oriental fruit moth (Biofix 3/30) 156 DD 185 DD 250 DD
Tufted apple bud moth

About degree-day models


April 21, 2020

apple orchardCool Weather Suppresses Insect Activity

With phenological stages ranging from petal fall to first cover throughout the region, insects of key concern remain the same as those discussed in last week’s update – plum curculio and oriental fruit moth for those at petal fall, and codling moth will become more important for those approaching first cover. However, the cool weather during the past week has suppressed activity of OFM and codling moth. These moth pests are most active in the first few hours after dusk, but only when temperatures exceed 62 to 65°F. With the cool temperatures during the past week, pheromone trap captures declined considerably this week compared to last week. With cool temperatures forecast for the next week, expect pheromone trap captures to remain low.

In contrast to moth pests, plum curculio is active during daylight hours when temperatures exceed 60°. Considering that daytime temperatures have often exceeded 60° in the past week (albeit, for only a few hours), the potential for damage still exists with this pest, although there is likely to be less damage than when temperatures exceed 70°.

Petal Fall Insecticide Recommendations:

In last week’s table of petal fall insecticide recommendations, I forgot to include the new diamide insecticide Verpedryn 100SL, which was approved for use on apples last fall. This insecticide belongs to the same class of insecticides that includes Altacor and Exirel. Hence, for rotational purposes it should be considered as having the same mode of action as these products. Similar to other diamides it is highly effective against key lepidopteran pests (OFM, codling moth, leafrollers, etc.), but also has exhibited good activity against plum curculio.

Relative Efficacy Chart for Petal Fall Insecticide Options

(― = No activity; P = poor; F= Fair; G = Good, E = excellent)

Insecticide Plum curculio Oriental fruit moth Rosy apple aphid Toxicity to bees
Actara E F E Highly toxic
Altacor E Low toxicity
Assail F G E Mod. toxic
Avaunt G G Mod. toxic
Beleaf E Low toxicity
Delegate P E Mod. toxic
Imidacloprid P P E Highly toxic
Imidan E E Mod. toxic
Sivanto E Low-Mod toxicity
Verdepryn G E Highly toxic
Versys E Low toxicity
Voliam Flexi* E E E Highly toxic

*Voliam Flexi is a premix that includes thiamethoxam (Actara) and chlorantraniliprole (Altacor)


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 7 Apr 14 Apr 20
Codling moth  0.0 0.0 0.1
Oriental fruit moth 24.5 9.4 0.1
Tufted apple bud moth 0.0 0.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 1.0 0.1
Brown marmorated stink bug (unsprayed) 0.3 1.0 0.1
Spotted tentiform leafminer 0.0 2.0 0.0
Dogwood borer
Peachtree borer 0.0 0.0
Lesser peachtree borer 1.0 0.0
San Jose scale 0.0 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

HENDERSON COUNTY
Apr 7 Apr 14 Apr 20
Codling moth
Oriental fruit moth (Biofix 3/30) 75 DD 156 DD 185 DD
Tufted apple bud moth

About degree-day models


April 14, 2020

orchard in bloomPetal Fall Spray Options

In many locations petal fall is approaching, and options for insecticides to spray will depend on what was applied before bloom and whether or not OFM mating disruption is being used. Another consideration is the level of bee activity in an orchard. For insecticides toxic to bees, which include most recommended at petal fall, labels restrict application of those insecticides until after bee hives have been removed from an orchard. Also, in situations where hives are in nearby orchards, applications should not be made if bees are foraging on flowers in the ground cover.

The key pests targeted at petal fall sprays include rosy apple aphid, plum curculio, and oriental fruit moth (OFM). See the table below for insecticide options.

Plum Curculio: This remains one of the most common causes of insect damage to apples in this region, and effective control is highly correlated with petal fall sprays. Although the severity of damage varies considerably among orchards, plum curculio is ubiquitous and can cause damage in virtually every orchard. In orchards with a history of problems, sprays should be made as quickly after petal fall as possible. In orchards where damage is historically low, there is usually a longer buffer period and sprays can be slightly delayed. However, 1st Cover is often too long to wait.

Rosy Apple Aphid:  Rosy apple aphid is a sporadic pest, but it can be difficult to monitor, and control with curative applications of insecticides can be difficult. Most neonicotinoids and closely related insecticides are effective against RAA, and effective control can be achieved when applied before bloom at Pink, or after bloom at petal fall, or in some instances as late as 1st Cover.

Oriental Fruit Moth:  Biofix in at the research station in Henderson County was set on 30 March. Although we did not have traps set off the mountain, biofix is typically at least 7 to 10 days earlier. In orchards using mating disruption for OFM, insecticidal control of the first generation is not necessary, and it is only necessary to focus on plum curculio. However, where mating disruption is not used, an insecticide effective against this pest is recommended to control the first generation.

Codling Moth:  At the research station in Henderson County we have not yet captured our first codling moth. However, they are active off the mountain, with high numbers reported from some locations. It is important to remember that while high numbers can be captured shortly after emergence, there is a lag time between emergence and when egg laying begins. Applications at petal fall or shortly thereafter are not recommended unless relying on insecticides that act primarily as ovicides. However, most recommended insecticides target first instar larvae when they hatch from eggs. Hence, waiting until 200 DD after biofix (about first cover) is sufficient even when early season trap captures are high.

Relative Efficacy Chart for Petal Fall Insecticide Options

(― = No activity; P = poor; F= Fair; G = Good, E = excellent)

Insecticide Plum Curculio OFM RAA Toxicity to Bees
Actara E F E Highly toxic
Altacor E Low toxicity
Assail F G E Mod. toxic
Avaunt G G Mod. toxic
Beleaf E Low toxicity
Delegate P E
Imidacloprid P P E Highly toxic
Imidan E E Mod. toxic
Sivanto E Low-Mod toxicity
Voliam Flexi* E E E Highly toxic

*Voliam Flexi is a premix that includes thiamethoxam (Actara) and chlorantraniliprole (Altacor)


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Mar 31
Apr 7
Apr 14
Codling Moth 0.0 0.0
Oriental Fruit Moth 7.5 24.5 9.4
Tufted Apple Bud Moth 0.0
Redbanded Leafroller 4.0 0.0 0.0
Obliquebanded Leafroller
Lesser Appleworm
Apple Maggot (abandoned and research)
Brown Marmorated Stink Bug (commercial – mountains) 1.0
Brown Marmorated Stink Bug (commercial – upper Piedmont)
Brown Marmorated Stink Bug (research – unsprayed) 0.3 1.0
Spotted Tentiform Leafminer 0.0 0.0 2.0
Dogwood Borer
Peachtree Borer 0.0
Lesser Peachtree Borer 0.0
San Jose Scale 0.0 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

  Henderson County
 Biofix Apr 7 Apr 14
Codling Moth
Oriental Fruit Moth March 30 75 144
Tufted Apple Bud Moth

About degree-day models


April 7, 2020

apple blossomsTrapping Continues

This past weekend CALS administration granted the apple entomology program permission to begin our insect monitoring program in commercial orchards. Of course we will need to follow social distancing and sanitation practices to avoid transmission of the coronavirus. We set up some of our trapping sites today, which will help to improve our insect activity updates and recommendations.

Green Fruitworm

While bloom is a time when the need for apple insect control takes a hiatus, scouting for green fruitworm feeding damage to new shoots should be conducted in a week or so to determine the need for control. The green fruitworm is a generic term that refers to a complex of three lepidopteran species of fruitworms that have comparable life histories and cause similar damage to apple. They are generally considered sporadic pests that do not occur every year. Since foliage feeding damage precedes fruit damage, scouting for damage can help determine the need for insecticidal control.

Green Fruitworm damage to young appleDescription and Life History: There are at least three species of noctuid moths that are commonly referred to as green fruitworm on apple, with the speckled green fruitworm, the widestriped green fruitworm, and the humped green fruitworm being the most commonly encountered. These insects have a wide host range that includes deciduous shade, forest and fruit trees and shrubs. Some species, such as the humped green fruitworm, lay eggs in the late fall and larvae hatch near bloom. Other species emerge as adults in the early spring near green tip and lay eggs on twigs and leaves up to early bloom. Larvae feed on both foliage and fruit, with the damage to fruit occurring any time between early fruit set to first cover.

Damage: Many, but not all, apples damaged by green fruitworms abort. Some will remain through harvest and exhibit deep corky scars and indentations. Shown below is some fresh feeding on apple, some older scars on small fruit, and a file photo of damaged fruit at harvest.

Pictures of green fruitworm damage. Fresh feeding on apple, older feeding scars on fruit, damaged fruit at harvest.

Monitoring for GFW: Because green fruitworms are considered sporadic pests, it is advisable to monitor for their presence before making the decision to apply an insecticide specifically targeting them. Fruitworm larvae feed more on foliage than fruit, and feeding damage to foliage precedes damage to fruit. Hence, the presence of feeding damage on new shoot growth on early-maturing varieties can used as a guide to the presence or absence of larvae in an orchard.

GFW feeding damage on foliage.

GFW feeding damage on foliage.

Control: Damage to fruit can occur shortly after new fruit are formed, and before all petals have fallen off of a tree. Hence, the need to protect bees and delay petal fall sprays until late-maturing varieties have reached the true petal fall stage in orchards with multiple varieties can lead to increased levels of damage on earlier blooming varieties. Therefore the most effective approach to control green fruitworms is to apply an insecticide that is non-toxic to bees at early petal fall. The only two insecticides that meet the criteria of controlling fruitworm and being safe to bees are Intrepid (6 oz/acre) and a Bacillus thuringiensis product such as Dipel, Xentari or Agree.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Mar 17
Mar 31
Apr 7
Codling Moth 0.0
Oriental Fruit Moth 0.0 7.5 24.5
Tufted Apple Bud Moth
Redbanded Leafroller 7.0 4.0 0.0
Obliquebanded Leafroller
Lesser Appleworm
Apple Maggot (abandoned and research)
Brown Marmorated Stink Bug (commercial – mountains)
Brown Marmorated Stink Bug (commercial – upper Piedmont)
Brown Marmorated Stink Bug (research – unsprayed) 0.3
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer
Peachtree Borer
Lesser Peachtree Borer
San Jose Scale 0.0

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

  Henderson County
 Biofix
Codling Moth
Oriental Fruit Moth
Tufted Apple Bud Moth

About degree-day models


March 31, 2020

apple orchard and trapsCoronavirus Impact on Apple Pest Recommendations

The coronavirus situation has sidelined our field activities for the timing being, so we are unable to monitor and assess pest activity in the region as we normally do. We are hopeful that we will be able to begin some field activities in the near future. Meanwhile, we do have several insect development models that are quite accurate for the timing of critical insecticide applications. What we are not able to do during this period is estimate pest density. Hence, website recommendations for the near future will be based on model predictions more so than actually captures in the field. Again, we are hopeful that can begin some field activities soon.

Now is the Time to Complete Installing Mating Disruption and Setting Pheromone Traps

Codling moth trap

Codling moth trap in upper-third of tree

By now most growers have completed their prebloom insecticide applications and are entering bloom. As we proceed through bloom, the most important objective is to avoid pesticide applications that are toxic to bees. With the possible exception of fruitworms that appear towards the end of bloom, there is no reason for insecticide applications until petal fall.

Mating Disruption:  For those using mating disruption for codling moth and oriental fruit moth (OFM), now is a good time to complete deploying dispensers. Ideally dispensers should be hung before codling moth biofix, which generally coincides with full bloom of ‘Delicious’ apples; in orchards with very low codling moth populations (i.e., where mating disruption has been used in previous years) biofix often occurs later. Also, hand-applied dispensers are much easier to deploy before trees are in full bloom or when they begin to leaf out.

OFM flight is well underway in lower elevations in the piedmont and foothill areas, and OFM are beginning to emerge in higher elevations such as Henderson County (2100 ft). Deployment of mating disruption dispensers before OFM biofix is less critical than for codling moth, because the first generation can be easily controlled with a single insecticide application at petal fall of apples (closer to shuck split or slightly later in peaches). Insecticide choices at petal fall will be covered in future posts.

Wing trap

Wing trap

Delta trap

Delta trap

Pheromone Traps: Now is also a good time to hang pheromone traps for codling moth, and OFM if they have not yet been deployed. Both wing and Delta style traps are appropriate for codling moth and OFM, but it is our experience that Delta traps are much easier to service. Also, it is recommended that traps be placed in the upper third of the tree canopy if possible, because this is where flight activity is most common. Finally, use of the same pheromone lure we have used in our research is important if our recommendations are to be relevant to your trap captures. OFM and codling moth lures we have used in our research have been Trécé brand OFM L2 and CM L2, with the L2 indicating they are long-life lures. L2 lures are loaded with a higher dose of pheromone compared to standard lures, and only need to be changed at 12-week intervals, compared to 4-wk intervals for standard lures.

Ambrosia Beetle Survey – Your Participation is Needed

A group of scientists in the Eastern US who are collaborating on ambrosia beetle research (including the NC  Apple Team) are conducting a survey to better understand the severity of ambrosia beetles on both a spatial and economic scale. The survey is coordinated by the University of Georgia, and is being sent to producers of ornamentals, apples, peaches and pecans. The results of the survey will be used to help set research and extension priorities, and in grant proposals to document the importance of ambrosia beetles to stakeholders.

The survey will only take 5 to 7 minutes, so please participate and Help your Apple Team Help You!

Follow the link below to take the survey:

https://ugeorgia.ca1.qualtrics.com/jfe/form/SV_0ojFgygi2BFmQ1n


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Mar 11
Mar 17
Mar 31
Codling Moth
Oriental Fruit Moth 0.0 0.0 7.5
Tufted Apple Bud Moth
Redbanded Leafroller 3.0 7.0 4.0
Obliquebanded Leafroller
Lesser Appleworm
Apple Maggot (abandoned and research)
Brown Marmorated Stink Bug (commercial – mountains)
Brown Marmorated Stink Bug (commercial – upper Piedmont)
Brown Marmorated Stink Bug (research – unsprayed) set
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer
Peachtree Borer
Lesser Peachtree Borer
San Jose Scale

*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2020 Accumulated Degree Days

  Henderson County
 Biofix
Codling Moth
Oriental Fruit Moth
Tufted Apple Bud Moth

About degree-day models


Additional Resources: