Skip to main content

NC State Extension

WNC Orchard Insect Populations

June 30, 2020

Throughout 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


2020 Pest Trends (click to enlarge)

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


PREVIOUS REPORTS

June 23, 2020

We 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

Codling 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

Codling 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

Codling 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

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

Cooler 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

Petal 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

Picture of 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.

Description 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

Picture of 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: