WNC Orchard Insect Populations for May 8, 2018

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Moth trapMay 8, 2018

Biofix dates now have been set for the three key lepidopteran pests of apples in the Hendersonville area. Biofix dates are 2 April for oriental fruit moth, 30 April for codling moth, and 4 May for tufted apple bud moth. Although we have not captured moths in lower elevation orchards in Polk or Cleveland Counties, historically biofix occurs about 6 days earlier in these locations.

In Henderson County, oriental fruit moth trap captures have declined considerably during the past two weeks and the overwintering generation is dying out. Insecticides applied at petal fall, or mating disruption if using it, should have controlled OFM at this time.

Based on the 30 April biofix date for codling moth, 93 DD have accumulated, so the timing of the initial application for first-generation codling moth in Henderson County is predicted for 7 to 10 days. In orchards using mating disruption, insecticides targeting codling moth are not recommended until early to mid June, which will coincide with the timing needed for tufted apple bud moth.

In lower elevation orchards not using mating disruption, an insecticide targeting coding moth is recommended at this time if they have been captured in pheromone traps. If none have been captured, it is OK to delay this application for at least another 10 days.

Insecticides targeting plum curculio should have already been applied to most varieties. If an insecticide effective against this pest has not yet been made on late blooming cultivars, this should be done at soon as trees are free of pollinators.

Finally, for those who are targeting San Jose scale with post-bloom insecticide applications (Esteem, Centaur or Movento), there remains about a 2-week window of opportunity to apply these treatments and still obtain good control.

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

2018 Average Weekly Trap Captures*

Insects per trap
Apr 23
Apr 30
May 7
Codling Moth 0.0 0.5 4.5
Oriental Fruit Moth 90.0 38.0 16.0
Tufted Apple Bud Moth 0.0 0.0 13.0
Redbanded Leafroller 2.0 1.0 0.0
Obliquebanded Leafroller 0.0 0.0 0.0
Lesser Appleworm 0.0 0.0 0.0
Apple Maggot
Brown Marmorated Stink Bug (commercial – mountains) 0.0 0.0 0.0
Brown Marmorated Stink Bug (commercial – upper piedmont) 0.3 1.3 1.3
Brown Marmorated Stink Bug (research – unsprayed) 0.3 0.3 2.3
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer 0.0 0.0
Peachtree Borer 0.0 0.0 1.0
Lesser Peachtree Borer 0.0 13.0 139.0
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 Apr 23
Apr 30
May 8
Codling Moth Apr 30 93
Oriental Fruit Moth Apr 2 171 247 372
Tufted Apple Bud Moth May 4 52
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.


  • 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.


  • 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.


  • 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)

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