WNC Orchard Insect Populations for May 22, 2018

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apple orchardMay 22, 2018

The codling moth is the major insect pest of concern at this time, in both the mountains and piedmont regions. Cumulative degree days since biofix are about 360 in Henderson County and 475 in Cleveland County. Although pheromone traps should be used to dictate the need for the number of sprays to make against the first generation, in the majority of orchards two applications should be made; ideally one now and another in 2 weeks. Only one application is needed in mating disruption orchards, and that should be timed to coincide with tufted apple bud moth during the first or second week of June.

Many of the overwintered Brown marmorated stink bug adults have emerged from overwintering sites, and emergence should be complete in the mountains in the next week or two. Emergence is likely complete off the mountain in lower elevations. We are beginning to pick up adults on pheromone traps in apple orchards, with numbers varying considerably among sample sites. Overall, traps average about 2.6 adults per trap across 27 sample sites. High populations of the overwintering generation sometimes require control, and the optimum timing of an application is the last week of May or first week of June. In those situations an application of a neonicotinoid is recommended, with Actara and Belay the best choices. For those using Voliam Flexi, that contains the active ingredients in both Altacor and Actara.

There have been some reports of European red mite already appearing in apples. This is very early, although not unprecedented. Early mite populations are probably related to the extensive use of pyrethroids last year for BMSB. While the heavy rains have probably slowed down mite buildup, it would be wise to start monitoring for ERM at this time.

Compatibility of Movento with Products Containing Spreader Stickers:  For those growers who are using preventive applications of Movento for management of San Jose scale and/or woolly apple aphid, be sure to read the label about the need for a penetrating surfactant to enhance leaf uptake of this systemic insecticide. Of equal importance is to avoid using surfactants with sticking properties or pesticide products that contain built in stickers. These types of surfactants can interfere with leaf uptake of Movento. If a product containing a sticker or an adjuvant with sticker properties must be used, do not apply Movento and spray it by itself at another time.

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

2018 Average Weekly Trap Captures*

Insects per trap
May 7
May 14
May 22
Codling Moth 4.5 1.0 1.8
Oriental Fruit Moth 16.0 6.7 4.3
Tufted Apple Bud Moth 13.0 6.0 12.0
Redbanded Leafroller 0.0 0.0 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 n/a 2.7
Brown Marmorated Stink Bug (commercial – upper piedmont) 1.3 n/a 0.7
Brown Marmorated Stink Bug (research – unsprayed) 2.3 0.5 2.2
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer 0.0 3.0 26.0
Peachtree Borer 1.0 1.0 0.0
Lesser Peachtree Borer 139.0 98.0 47.0
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 8
May 14
May 22
Codling Moth Apr 30 93 196 358
Oriental Fruit Moth Apr 2 372 503 706
Tufted Apple Bud Moth May 4 52 184 386
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.