WNC Orchard Insect Populations for May 30, 2018

— Written By and last updated by

May 30, 2018Image of stream

The recent heavy rain has significantly suppressed insect activity. Trap captures for most insects were fairly low this week. However, when sunshine and warm weather return, you can expect the insect world to return to normal rather quickly. So for the next week, the insects of greatest concern are codling moth and tufted apple bud moth.

Depending on location, degree-day (DD) accumulations for codling moth range from about 530 in Henderson County to almost 700 in Cleveland County. If you are uncertain of your codling moth population, you should assume that codling moth will remain a threat for the next two weeks in Henderson County. Off the mountain, populations are nearing the end of the first generation flight, and the window for first generation control will close within in the next week.

Tufted apple bud moth DD accumulations range from about 660 in Henderson County to about 870 in Cleveland County, although TABM is generally not an issue outside of Henderson County. An insecticide effective against TABM during the next week should control the first generation. Regardless of whether one is using Altacor or Delegate for first generation codling moth, both products are excellent against TABM. If codling moth control is not required at this time, other options for excellent TABM control are Intrepid and Rimon, as well as the premix products Voliam Flexi, Besiege, Cormoran, and Minecto Pro.

The Comstock mealy bug is a sporadic pest that is most common in Polk County;  rarely is it a problem in other apple producing locations in NC. In those areas where this insect has a history of infesting the calyx end of fruit, now is the time for insecticide applications targeting this pest. There are not a lot of insecticides effective against this mealy bug, the most effective being Assail (or premixes containing acetamiprid) or Movento.

Finally, European red mite continues to be observed in more orchards than usual for this time of the year. With the rains letting up, expect ERM populations to continue to build up.


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


2018 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
May 14
May 22
May 29
Codling Moth 1.0 1.8 3.5
Oriental Fruit Moth 6.7 4.3 5.7
Tufted Apple Bud Moth 6.0 12.0 12.0
Redbanded Leafroller 0.0 0.0 0.0
Obliquebanded Leafroller 0.0 0.0 1.0
Lesser Appleworm 0.0 0.0 0.0
Apple Maggot 0.0
Brown Marmorated Stink Bug (commercial – mountains) n/a 2.7 1.3
Brown Marmorated Stink Bug (commercial – upper piedmont) n/a 0.7 3.7
Brown Marmorated Stink Bug (research – unsprayed) 0.5 2.2 0.3
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer 3.0 26.0 31.0
Peachtree Borer 1.0 0.0 1.5
Lesser Peachtree Borer 98.0 47.0 25.0
San Jose Scale 0.0 0.0 0.0

*Note that averages presented here are intended only to illustrate the timing of insect emergence and fluctuations in population activity, and not as general indicators of population levels. Some orchards included in these averages have significantly higher or lower populations than most commercial orchards in the area, resulting in averages that are sometimes skewed from what is typical. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2018 Accumulated Degree Days

  Henderson County
 Biofix May 14
May 22
May 29
Codling Moth Apr 30 196 358 501
Oriental Fruit Moth Apr 2 503 706 883
Tufted Apple Bud Moth May 4 184 386 564
About degree-day models: The degree day (DD) models predict adult emergence and egg hatch of each generation. They do not predict the intensity of populations, which can be assessed by using pheromone traps. Hence, the models should be used to help gauge the time period when control is most likely needed, and pheromone traps provide information on the need for and frequency of insecticide applications. For full details, read “IPM Practices for Selected Pests” in the Orchard Management Guide.

CODLING MOTH:

  • 1st generation: Egg hatch begins at about 350 DD after biofix and is completed by 1050 DD. The most critical period for insecticidal control is from 350 to about 750 DD.
  • 2nd generation: Egg hatch of the second generation can extend from about 1300 to 2600 DD after biofix, but the most critical period for insecticidal control is 1400 to about 2500 DD.
  • 3rd generation: Adults begin to emerge at about 2500 DD after biofix, but the model is less accurate in predicting late-season populations.

ORIENTAL FRUIT MOTH:

  • 1st generation: Only one insecticide application between 400 and 500 degree days is usually necessary, as 1st generation egg-laying is usually low on apple.
  • 2nd generation: Effective 1st-generation control may eliminate the need for 2nd-generation control. If trap captures remain high, insecticides may be needed around 1100 to 1400 DD.
  • 3rd generation: Insecticide may be needed at 2200 DD after biofix.
  • 4th generation: Overlapping generations late in the season make it difficult to predict when 4th-generation egg hatch begins, but continuous egg-laying can occur from August through October. Use traps to determine the need for further insecticide applications.

 TUFTED APPLE BUD MOTH:

  • 1st generation: One well-timed insecticide application between 800 and 1200 DD after biofix will often eliminate the need for further control of TABM.
  • 2nd generation: Only if trap captures exceed 25 moths per trap by 2600 DD is an insecticide application recommended. NOTE: Insecticides targeting 2nd generation TABM are usually not necessary if 1st generation populations were successfully controlled.

2018 Pest Trends (click to enlarge)

Slide 1 image Slide 2 image Slide 3 image Slide 4 image Slide 5 image Slide 6 image Slide 7 image Slide 8 image Slide 9 image Slide 10 image Slide 11 image Slide 12 image Slide 13 image

Written By

Photo of Jim Walgenbach, N.C. Cooperative ExtensionDr. Jim WalgenbachExtension Entomology Specialist (Fruits / Vegetables) (828) 687-0570 (Office) jim_walgenbach@ncsu.eduEntomology and Plant Pathology - NC State University
Updated on Jun 21, 2018
Was the information on this page helpful? Yes check No close
Scannable QR Code to Access Electronic Version This page can also be accessed from: go.ncsu.edu/readext?530084