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NC State Extension

WNC Orchard Insect Populations

June 15, 2021

BMSB life stages (L to R): 2nd, 3rd, 4th, 5th instars; M and F adults

BMSB life stages (L to R): 2nd, 3rd, 4th, 5th instar nymphs; male and female adults

Codling moth model DD accumulations range from about 810 in Henderson County to about 1150 in Cleveland County. These values coincide with >95% emergence of first generation moths in Henderson County to completion of first generation flight in lower elevations. Except for those orchards with high populations and where there is little drop in pheromone trap captures, insecticidal control of this pest should not be necessary until about 1400 DD, or when second generation egg hatch begins.

Where tufted apple bud moth is a concern, the window of opportunity to apply an insecticide for season-long control remains open. For growers who have not applied an insecticide effective against TABM in the past 3 weeks, an application should be considered.

For those wondering about the status of brown marmorated stink bug, overwintered adults have completed emergence and are now laying eggs. Based on degree-model predictions, first generation egg laying is approximately 30%, 40% and 60% complete in Henderson, Wilkes and Cleveland Counties, respectively. Some of these eggs have hatched and small to medium sized nymphs are present. While most eggs are laid on wild hosts adjacent to orchards, egg laying can sometimes occur within orchards, especially on peaches. Also, migration of nymphs from wild hosts onto orchard trees adjacent to woods is also possible. Control of nymphs is generally easier than adults, and most neonicotinoids, including imidacloprid, will control these individuals. Emergence of the more damaging F1 adult generation is not expected for at least another 4 weeks (at less than 1000 ft elevation) to 8 weeks (at >2000 ft elevation).


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 1 Jun 7 Jun 14
Codling moth  3.5 0.0 2.0
Oriental fruit moth 6.0 13.0 17.0
Tufted apple bud moth 28.0 14.0 2.0
Redbanded leafroller 0.0 1.0 0.0
Obliquebanded leafroller 18.0 35.0 18.0
Lesser appleworm 9.0 4.0 0.0
Apple maggot (abandoned and research orchards) 0.5 0.0 0.0
Brown marmorated stink bug (commercial) 1.7 1.8 1.0
Brown marmorated stink bug (unsprayed) 0.5 1.5 7.5
Spotted tentiform leafminer 3.0 0.0 20.0
Dogwood borer 36.0 54.0 38.0
Peachtree borer 0.0 5.0 6.0
Lesser peachtree borer 48.0 51.0 52.0
San Jose scale 0.0 5.0 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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Jun 1 Jun 7 Jun 14
Codling moth (Biofix: April 10)
523 632 792
Oriental fruit moth (Biofix: March 27)
849 988 1183
Tufted apple bud moth (Biofix: April 30)
490 629 824

About degree-day models


2021 Pest Trends (click to enlarge)

Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends Chart showing insect population trends


PREVIOUS UPDATES

Apple tree shoots damaged by potato leafhopperJune 8, 2021

Codling moth degree-day accumulations range from about 630 in Henderson County to approximately 960 DD in Cleveland County. At this stage codling moth remains a potential threat in Henderson County and locations with a similar or higher elevation (≥ 2000 ft), while in lower elevations (Cleveland/Lincoln Co) first generation flight is nearly complete.

In locations where tufted apple bud moth is a concern, the window of opportunity for control will be nearing an end in lower elevations, while in orchards above 2000 ft the window will remain open for at least 7 to 10 days.

Second generation oriental fruit moth flight is underway in most regions, but typical of this generation, numbers are very low.

Mid-June is prime time for green apple aphids, potato leafhopper, and European red mite, so monitoring for these pests is important at this time.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 24 Jun 1 Jun 7
Codling moth  5.5 3.5 0.0
Oriental fruit moth 7.0 6.0 13.0
Tufted apple bud moth 22.0 28.0 14.0
Redbanded leafroller 0.0 0.0 1.0
Obliquebanded leafroller 8.0 18.0 35.0
Lesser appleworm 12.0 9.0 4.0
Apple maggot (abandoned and research orchards) set 0.5 0.0
Brown marmorated stink bug (commercial) 2.0 1.7 1.8
Brown marmorated stink bug (unsprayed) 0.5 0.5 1.5
Spotted tentiform leafminer 0.0 3.0 0.0
Dogwood borer 21.0 21.0 54.0
Peachtree borer 0.0 0.0 5.0
Lesser peachtree borer 42.0 42.0 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.


2021 Accumulated Degree Days

HENDERSON COUNTY
May 24 Jun 1 Jun 7
Codling moth (Biofix: April 10)
395 523 632
Oriental fruit moth (Biofix: March 27)
681 849 988
Tufted apple bud moth (Biofix: April 30)
323 490 629

About degree-day models


Tree in an orchardJune 2, 2021

Codling moth degree-day accumulations range from about 530 in Henderson County to 825 in Cleveland/Lincoln Counties. Hence, it remains a potential threat in Henderson County and other locations of similar elevation (≥2,000 ft) with about 80% of first generation adults emerged and 30% of first generation eggs hatched. In lower elevations of Cleveland and Lincoln, first generation flight is nearly complete, with essentially all adults emerged from overwintering and almost 70% of eggs hatched. Once we pass about 650 DD, further insecticide sprays for codling moth are usually not necessary until second generation.

For those locations where tufted apple bud moth is a concern, the ideal timing for control generally occurs during the first two weeks of June. Biofix was curiously late this year, so based on DD accumulations (about 500 in Henderson County) it is still a bit early, but most insecticides should provide the residual control necessary for season-long control. Insecticides recommended include the group 28 MOA diamides such as Altacor, Exeril, or Verdepryn, the group 5 spinosyn Delegate, or Group 18 ecdysone agonist Intrepid.

For those using mating disruption for codling moth and who have not yet applied an insecticide, one of the above materials for TABM is an important spray.

Second generation oriental fruit moth flight has begun emergence in lower elevations, and is expected to begin in Henderson County next week. However, this flight is generally very low and rarely of concern.

Finally, expect leafhoppers, aphids and mites to continue to be observed with greater frequency, so monitoring for these secondary pests is important during the entire month of June.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 17 May 24 Jun 1
Codling moth  2.5 5.5 3.5
Oriental fruit moth 3.0 7.0 6.0
Tufted apple bud moth 10.0 22.0 28.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 8.0 18.0
Lesser appleworm 0.0 12.0 9.0
Apple maggot (abandoned and research orchards) set 0.5
Brown marmorated stink bug (commercial) 1.0 2.0 1.7
Brown marmorated stink bug (unsprayed) 0.5 0.5 0.5
Spotted tentiform leafminer 0.0 0.0 3.0
Dogwood borer 10.0 21.0 36.0
Peachtree borer 0.0 0.0 3.0
Lesser peachtree borer 33.0 42.0 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.


2021 Accumulated Degree Days

HENDERSON COUNTY
May 17 May 24 Jun 1
Codling moth (Biofix: April 10)
298 395 523
Oriental fruit moth (Biofix: March 27)
550 681 849
Tufted apple bud moth (Biofix: April 30)
191 323 490

About degree-day models


Tractor in a fieldMay 25, 2021

As has been the case for the past several weeks, codling moth remains the greatest threat throughout the region, although low populations make the risk of damage low in many orchards. Now is also a good time to begin scouting for secondary pests, including European red mite, aphids and leafhoppers.

Codling moth: Degree-day accumulations range from about 400 in Henderson County to 650 in Lincoln/Cleveland County. In the lower elevation orchards (i.e., Lincoln/Cleveland), first generation flight should decline over the next week or so. In Henderson County (and orchards at a similar elevation of about 2000 ft), we will be entering the main flight and egg-laying period of the first generation. In orchards being managed as if full crop, the next 7 to 10 days will be an important time to monitor populations, or apply an insecticide if not monitoring.

In lower elevations where tufted apple bud moth (TABM) is a concern, an insecticide applied anytime during the next two weeks is good timing. In Henderson County, the window for control of TABM will not begin for another 7 to 14 days.

Secondary Pests:  While it may seem early for European red mite, in orchards with high populations it is not unusual for mites to be observed by late May. We are also on the early side of potato leafhopper and green apple aphids, but a few leafhoppers, although too low to justify treating, were observed in our plots yesterday. Finally, in our research plots where rosy apple aphid (RAA) was not controlled early in the spring, aphids are continuing to spread. If RAA-curled leaves are observed in orchards, these leaves should be checked for the presence of live aphids. As temperatures warm, RAA populations will decline.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 10 May 17 May 24
Codling moth  4.5 2.5 5.5
Oriental fruit moth 11.5 3.0 7.0
Tufted apple bud moth 2.0 10.0 22.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 8.0
Lesser appleworm 0.0 0.0 12.0
Apple maggot (abandoned and research orchards) set
Brown marmorated stink bug (commercial) 1.0 2.0
Brown marmorated stink bug (unsprayed) 1.0 0.5 0.5
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 1.0 10.0 21.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 29.0 33.0 42.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
May 10 May 17 May 24
Codling moth (Biofix: April 10)
243 298 395
Oriental fruit moth (Biofix: March 27)
467 550 681
Tufted apple bud moth (Biofix: April 30)
108 191 323

About degree-day models


May 18, 2021Periodical cicada on apple tree

Codling moth remains the primary concern across the region, with degree-day accumulations since biofix ranging from about 300 DD in Henderson County to about 520 in the Cleveland/Lincoln County area. As highlighted in last week’s update, insecticide recommendations vary depending on how an orchard is being managed – i.e., a full crop versus one that is questionable as to whether or not to manage.

In higher elevations (Henderson, Haywood, Wilkes) being managed as a full crop, insecticidal control of codling moth is recommended an upcoming spray. In situations with a low codling moth population and which have not yet been sprayed for codling moth, an application should be made at about 350 DD, which is later this week in these locations. In lower elevations where DD accumulations are about 520, it should be remembered that an application between 500 and 650 DD will coincide the optimum timing for control of tufted apple bud moth. While first generation codling moth can remain a concern up to about 900 DD, in most situations insecticides are not needed beyond 600 and 650 DD.

In orchards with a low crop load that do not justify a normal spray program, it would be wise to make a single insecticide application between 500 and 650 DD to target both codling moth and TABM.

Brood X of 17-year Cicada: There have been numerous stories in the press about emergence of Brood X of the 17-year cicada. Within our region, this brood is expected to be restricted to northeast Georgia and far western NC in Cherokee County, and should not be a concern for growers in other areas. Female cicadas lay eggs with a sharp ovipositor in the limbs of trees, and in large numbers they can do considerable damage to fruit trees. Most pyrethroids and neonicotinoids will control cicadas, but frequency of application will vary with the intensity of populations.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 3 May 10 May 17
Codling moth  15.5 4.5 2.5
Oriental fruit moth 11.5 11.5 3.0
Tufted apple bud moth 5.0 2.0 10.0
Redbanded leafroller 4.0 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) 1.0
Brown marmorated stink bug (unsprayed) 0.5 1.0 0.5
Spotted tentiform leafminer 2.0 0.0 0.0
Dogwood borer 0.0 1.0 10.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 42.0 29.0 33.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
May 3 May 10 May 17
Codling moth (Biofix: April 10)
177 243 298
Oriental fruit moth (Biofix: March 27)
372 467 550
Tufted apple bud moth (Biofix: April 30)
32 108 191

About degree-day models


May 11, 2021

Spraying apple orchardCodling Moth

We have entered a period where the main focus of insect control throughout the region is the codling moth, and it will remain that way for the next several weeks. Degree-day accumulations since biofix range from about 240 in Henderson County to 420 in the Lincoln/Cleveland County region. Under moderate to high codling moth populations, an initial application is recommended at 250 DD, which coincides with initial egg hatch. However, populations are considerably lower in the vast majority of commercial orchards, and delaying an application until approximately 350 DD will allow growers to reduce the number of applications targeting the first generation without risking damage. The last spray targeting first generation codling moth is generally between 600 to 650 DD. Pheromone trapping is an important tool to verify the existence of low populations. The forecast calls for below normal temperatures for the next week, so few degree-days will be accumulating during this time.

In those orchards that have employed mating disruption for codling moth and OFM, especially for multiple years, only one insecticide application for the first generation is recommended. The timing of this application should be between 500 and 650 DD, which also coincides with the optimum time for control of the tufted apple bud moth.

Insecticide Use in Orchards with Reduced Crops 

There have been questions about reduced insecticide programs in orchards with crop losses due to the freeze. This is a difficult question, and the answer depends on the extent of crop loss, the specific pest, and the historical insect pressure in the orchard. Certain insects, such as the codling moth and apple maggot, use chemical cues given off by fruit to help locate their hosts, so those orchards with few fruit will be less attractive than those with full crops. Certain other pests, such as scales, mites, aphids and leafhoppers, do not rely on these same chemical cues, and populations will infest trees regardless of fruit load.

Severe Crop Loss:  The easiest decision is in those orchards with no crop, or so few fruit that it is not economically viable to harvest. Under this scenario, insecticide use should be sparse and used only against those few insects that can do long-term damage to the health of the tree, or reduce return bloom next year. In orchards with a history of San Jose scale problems, an insecticide should be considered, because it can take a couple of years to clean up a large scale population. However, if scales have not been an issue for several years, which is best estimated by the absence of infested fruit at harvest, an insecticide is probably not necessary. Injury inflicted by high European red mite populations can reduce fruit set the following year, so a miticide should be considered if populations develop to high numbers – i.e., bronzing is evident. However, with a reduced insecticide program, ERM should be less of problem compared to normal circumstances. Another pest to consider controlling is potato leafhopper, especially on young trees. Leafhoppers prefer to feed on new shoot growth and can stunt growth when populations are allowed to build to high numbers.

Questionable Crop Load:  This is the most difficult situation, where the crop load is low, but perhaps not so low that you are willing to walk away from the orchard. Under this scenario the cost of a full management program is not justified. The only practical way to reduce insect control costs are to reduce the number of applications; there are no “less expensive insecticides” that provide acceptable levels of control, otherwise they would be recommended and used under normal circumstances. Clearly, there is risk associated with reducing the number of insecticide applications. The best way to minimize that risk is to scout orchards for pest problems on a regular basis, including the use of pheromone traps for codling moth and oriental fruit moth. I am familiar with low-pest population orchards in previous years that have not been sprayed with an insecticide for over two months from early June to mid August. So it is possible to minimize insecticide use with without incurring serious damage. Below are timings considered most critical for insecticide applications if minimizing cost inputs.

2nd to 3rd Cover: An insecticide effective against both codling moth and tufted apple bud moth applied between 500 and 600 codling moth DD.

Mid-June:  If leafhoppers are causing damage, consider an insecticide that is also has some activity against oriental fruit moth.

5th to 6th Cover: An insecticide effective against codling moth at about 1450 DD to target the second generation if moth captures in pheromone traps exceed 7 to 10 per week.

Mid-August to Early September:  Depending on the timing of emergence of 1st-generation brown marmorated stink bug adults, one or two pyrethroid applications to minimize damage.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 26 May 3 May 10
Codling moth  5.5 15.5 4.5
Oriental fruit moth 4.0 11.5 11.5
Tufted apple bud moth 0.0 5.0 2.0
Redbanded leafroller 12.0 4.0 0.0
Obliquebanded leafroller 0.0 0.0
Lesser appleworm 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.5 1.0
Spotted tentiform leafminer 0.0 2.0 0.0
Dogwood borer 0.0 0.0 1.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 4.0 42.0 29.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Apr 26 May 3 May 10
Codling moth (Biofix: April 10)
86 177 243
Oriental fruit moth (Biofix: March 27)
251 372 467
Tufted apple bud moth (Biofix: April 30)
32 108

About degree-day models


May 4, 2021San Jose scale trap

With the uncertainty of fruit loads and extended bloom period, many growers are just now applying a petal fall spray. Recommendations for petal fall were outlined in the April 15 update, with an emphasis on control of plum curculio.

Codling Moth:  In lower elevation orchards such as Lincoln and Cleveland Counties, codling moth degree-day accumulations have increased to 300, while in Henderson County they are only about 180 DD. First egg hatch begins at about 250 in orchards with moderate to high populations. However, in orchards with low populations, which includes most commercial orchards, initial applications can be made at about 350 DD. In Henderson County, 250 and 350 DD are predicted to occur on May 9 and 15, respectively. In Lincoln county 350 DD is predicted for later this week.

San Jose Scale: Another insect on the radar at this time is San Jose scale. Targeting first generation crawlers at first or second cover has become a popular strategy in recent years, and has worked well for those employing this tactic. Two commonly used and excellent materials are Esteem and Centaur, and for resistance management it would good to alternate these materials yearly. Also, studies last year showed that Assail at 6 oz/A also provided good control of a large SJS population.

The reason for the recommended timing of applications at 1st or 2nd cover is illustrated in the figure below that shows population trends of a large SJS population in apples in 2015. Crawlers began to emerge in mid-May, which is the optimum timing of applications in Henderson County. In lower elevations (Cleveland County), applications this week or next would be ideal.

Chart of San Jose scale population trends in 2015


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 19 Apr 26 May 3
Codling moth  7.5 5.5 15.5
Oriental fruit moth 20.0 4.0 11.5
Tufted apple bud moth 0.0 0.0 5.0
Redbanded leafroller 14.0 12.0 4.0
Obliquebanded leafroller 0.0
Lesser appleworm 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 0.5
Spotted tentiform leafminer 0.0 0.0 2.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 3.0 4.0 42.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Apr 19 Apr 26 May 3
Codling moth (Biofix: April 10)
67 86 177
Oriental fruit moth (Biofix: March 27)
216 251 372
Tufted apple bud moth (Biofix has not been established)

About degree-day models


April 27, 2021

Hummingbird moth


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 12 Apr 19 Apr 26
Codling moth  2.0 7.5 5.5
Oriental fruit moth 5-.0 20.0 4.0
Tufted apple bud moth 0.0 0.0 0.0
Redbanded leafroller 7.0 14.0 12.0
Obliquebanded leafroller
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 0.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 1.0 3.0 4.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Apr 12 Apr 19 Apr 26
Codling moth (Biofix: April 10)
46 67 86
Oriental fruit moth (Biofix: March 27)
152 216 251
Tufted apple bud moth (Biofix has not been established)

About degree-day models


April 20, 2021

Oriental fruit moths in trapCool Weather Will Suppress Insect Activity

Last week’s pest update provided options for insecticide applications at petal fall, emphasizing the importance of plum curculio control at this time, as well as oriental fruit moth in those orchards not using mating disruption. Highs for the remainder of this week are predicted to be in the 50s and 60s, and temperatures will not return to the 70s until next Monday. If petal fall insecticide sprays have not yet been applied, it would be advantageous to wait until early next week when pest activity again picks up to make applications.

Our codling moth biofix date for Henderson County was 10 April, and in Cleveland County it was estimated at 6 April. Hence, we are still at least 10 to 14 days and possibly longer before anticipated first sprays for first generation codling moth.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Apr 5 Apr 12 Apr 19
Codling moth  0.0 2.0 7.5
Oriental fruit moth 12.0 50.0 20.0
Tufted apple bud moth 0.0 0.0 0.0
Redbanded leafroller 9.0 7.0 14.0
Obliquebanded leafroller
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 0.0
Spotted tentiform leafminer 4.0 0.0 0.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 0.0 1.0 3.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Apr 5 Apr 12 Apr 19
Codling moth (Biofix: April 10)
46 67
Oriental fruit moth (Biofix: March 27)
56 152 216
Tufted apple bud moth (Biofix has not been established)

About degree-day models


April 15, 2021Apple blooms at edge of orchard

Petal Fall Spray Options

With petal fall spray imminent in most locations, insecticide options 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 many recommended at petal fall, it is important that bees are removed from orchards before sprays are applied.

The key insect pests to target at petal fall include plum curculio, oriental fruit moth and rosy apple aphid. Among these insects, the plum curculio presents the greatest threat, because petal fall is essentially the only time that it can be effectively controlled, while other options are available for OFM and rosy apple aphid.

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 before bloom at Pink, or after bloom at petal fall.

Oriental Fruit Moth:  Biofix at the research station in Henderson County was set on 27 March (codling moth biofix was 9 April). In orchards using mating disruption for OFM, insecticidal control of the first generation is not necessary, so focus on plum curculio and rosy apple aphid if relevant. However, where mating disruption is not used, an insecticide effective against this pest is recommended to control the first generation.

Insecticide Options:  Because of the importance of plum curculio, only those insecticides with activity against this pest are recommended at petal fall.

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
Assail F G E Mod. toxic
Avaunt G G Mod. toxic
Imidan E E Mod. toxic
Verdepryn G E Highly toxic
Voliam Flexi* E E E Highly toxic
*Voliam Flexi is a premix that includes thiamethoxam (a.i. in Actara) and chlorantraniliprole (a.i. in Altacor).

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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Mar 30 Apr 5 Apr 12
Codling moth  setup 0.0 2.0
Oriental fruit moth 17.5 12.0 50.0
Tufted apple bud moth setup 0.0 0.0
Redbanded leafroller 10.0 9.0 7.0
Obliquebanded leafroller
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 0.0 0.0
Spotted tentiform leafminer 0.0 4.0 0.0
Dogwood borer setup 0.0 0.0
Peachtree borer setup 0.0 0.0
Lesser peachtree borer setup 0.0 1.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
Mar 30 Apr 5 Apr 12
Codling moth (Biofix: April 9)
46
Oriental fruit moth (Biofix: March 27)
27 56 152
Tufted apple bud moth (Biofix has not been established)

About degree-day models


Written By

Jim Walgenbach, N.C. Cooperative ExtensionDr. Jim WalgenbachProfessor & Extension Entomology Specialist (Fruits / Vegetables) Call Dr. Jim Email Dr. Jim Entomology & Plant Pathology
NC State Extension, NC State University
Page Last Updated: 1 day ago
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