Current Western NC Orchard Pest Populations Aug 24, 2015

— Written By and last updated by

We track local insect populations throughout the growing season using a system of traps, temperature-recording devices, and degree-day models. Traps and weather data are checked weekly, with results updated by Tuesday afternoon from April through September. Learn more about southeastern apple pests at the Apple Pest Management page.

Weekly summary

AUGUST 24, 2015


Codling moth and oriental fruit moth remained relatively low during the past week. With the possible exception of OFM in some orchards that have not used mating disruption, this trend is expected to continue into September. It is uncommon for insect problems to suddenly appear in September in orchards that have not experienced at least some lepidopteran damage by this point in the year. As mentioned in previous weeks, the exception can be OFM. In orchards not using mating disruption, an application of sprayable OFM pheromone in mid to late August usually works as well or better than insecticides.

Apple Maggot.  Trap captures in abandoned orchards were low during the past week, and populations are probably on the decline at this point in the season.

Brown Marmorated Stink Bug.  BMSB captures in pheromone traps located in apple orchards in Henderson County have been relatively low, and little stink bug damage has been observed on apples. However, the situation may be quite different in hotspots in other locations, so there is no substitute for monitoring for damage in your own orchards, especially in the first few rows adjacent to woods.

 Average Weekly Trap Captures*

Insects per trap
Aug 10
Aug 17
Aug 24
Codling Moth
11.0 4.0 6.3
Oriental Fruit Moth
8.5 3.3 2.3
Tufted Apple Bud Moth 3.0 5.0 1.0
Redbanded Leafroller 1.5 0.0 0.0
Obliquebanded Leafroller 1.0 1.0 0.0
Lesser Appleworm 0.0 0.0 0.0
Apple Maggot 4.5 5.0 1.5
Brown Marmorated Stink Bug 0.5 0.5 0.3
Spotted Tentiform Leafminer 18.0 8.0 21.0
Dogwood Borer 17.0 4.0 10.0
Peachtree Borer 30.5 31.0 28.5
Lesser Peachtree Borer 28.5 57.0 35.5
San Jose Scale 325.0 512.5 1035.5

*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.

Accumulated Degree Days

Henderson County
 Biofix Aug 10
Aug 17
Aug 24
Codling Moth April 23 2184 2331 2500
Oriental Fruit Moth Apr 6 2936 3116 3322
Tufted Apple Bud Moth April 23 2676 2856 3062
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.