Current Western NC Orchard Pest Populations

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

DSC_7768July 28, 2014

Based on the codling moth degree-day model, Henderson County is currently in the middle of second generation flight, while off the mountain in Polk County the second generation flight is complete.  Pheromone trap captures in the few locations where significant populations exist agree with the model.  In the vast majority of orchards codling moths are very low and one insecticide application against the second generation is probably sufficient. Under such low densities the timing of that application is not highly critical, and last week or this week is OK in Henderson County.

Oriental fruit moth pheromone trap captures continued a two-week trend of declining numbers.  Lower numbers were likely due to the use of sprayable OFM pheromone in several of our monitoring orchards and insecticides applied for second generation codling moth.

Of particular significance was a relatively large jump in apple maggot captures on traps in our two abandoned orchards – they averaged 2 flies last week and 5 flies per trap this week.  Orchards located near abandoned sites are obviously at greatest risk of infestation.

 2014 Average Weekly Trap Captures*

Insects per trap Insects per trap
Jul 14
Jul 21
Jul 28
Jul 14
Jul 21
Jul 28
Codling Moth
3.5 3.4 3.4 0.1 0.1 6.5
Oriental Fruit Moth
35.8 31.6 22.8 2.3 0.5 1.5
Tufted Apple Bud Moth 0.5 2.0 1.0 0.0 1.0 1.0
Redbanded Leafroller 0.0 0.0 0.0 0.0 0.0 0.0
Obliquebanded Leafroller 1.0 0.0 0.0 1.0 7.0 1.0
Lesser Appleworm 0.0 0.5 0.0 0.0 1.0 1.0
Apple Maggot 0.0 1.0 2.5 0.0 0.0 0.0
Brown Marmorated Stink Bug 0.3 0.0 1.0 - - -
Spotted Tentiform Leafminer 46.0 34.0 24.0 - - -
Dogwood Borer 20.5 34.0 6.0 - - -
Peachtree Borer 46.5 43.0 41.5 - - -
Lesser Peachtree Borer 18.0 3.5 3.5 - - -
Plum Curculio 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.

2014 Accumulated Degree Days

Henderson County      Polk County
  Jul 14
Jul 21
Jul 28
  Jul 14
Jul 21
Jul 28
Codling Moth Biofix 5/2 1325 1441 1593 Biofix 5/2
1675 1819 2002
Oriental Fruit Moth Biofix 4/7 1973 2127 2310
Biofix 4/2
2447 2626 2844
Tufted Apple Bud Moth Biofix 4/28
1737 1891 2073 Biofix 4/21
2187 2366 2584

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.

2014 Pest Trends (click to enlarge)


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