WNC Orchard Insect Pest Update - May 19, 2026 - Southern Appalachian Apples

WNC Orchard Insect Pest Update - May 19, 2026

— Written by Jim Walgenbach — Contributors: Stephen Schoof | May 19, 2026

Small apples on tree with orange plastic insect trap in background, in orchard

In Henderson County and similar elevations, first generation codling moth and tufted apple bud moth (TABM) are the key pests of concern, whereas only a week or so of activity is expected to remain for these insects in lower elevations.

Cumulative codling moth and TABM degree-day (DD) accumulations in Henderson County are about 478 and 656, respectively, as of May 19. On average, DD accumulations are currently 5 days ahead of that in 2025 and 9 days ahead of the past 5-year average. Based on temperature forecasts, that gap is expected to widen over the next 10 days. Consequently, the window for TABM control is earlier than in past years, and in Henderson County 700 DDs for TABM is predicted for Thursday (May 21). Hence, an insecticide applied anytime over the next two weeks will provide season-long control of TABM. As mentioned in last week’s update, in some areas codling moth can remain intense through about 700-750 codling moth DDs, which is expected to be at least through the end of May.

In orchards that have very low codling moth populations and where insecticides have been held out in recent weeks, an application targeting TABM and codling moth is recommended in the next 7 to 14 days.

In Cleveland County and similar elevations, cumulative codling moth and TABM DDs are currently about 717 and 992, respectively. This is nearing the end of major activity of both insects.

Although we have not observed apple aphids or potato leafhoppers in plots on the research station or in commercial orchards, we are approaching that time when apple aphids and potato leafhoppers begin to appear. So keep an eye out for these pests on new shoot growth.

Chart showing codling moth degree-day accumulations for the last several years

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

2026 Average Weekly Trap Captures - Henderson County

	Insects per trap
Insect	Apr 13	Apr 20	Apr 27	May 4	May 11	May 18
Codling moth	1.5	1.0	1.0	0.0	0.5	1.0
Oriental fruit moth	58.0	44.5	21.0	7.0	8.0	2.0
Tufted apple bud moth	0.0	15.0	15.0	14.0	8.0	7.0
Redbanded leafroller	23.0	13.0	1.0	0.0	1.0	1.0
Obliquebanded leafroller	0.0	0.0	0.0	0.0	0.0	1.0
Lesser appleworm	set	2.0	6.0	8.0	6.0	3.0
Apple maggot (research orchard)	-	-	-	-	set	0.5
Brown marmorated stink bug (commercial)	4.5	1.0	2.0	0.0	0.8	1.3
Brown marmorated stink bug (unsprayed)	2.5	2.0	0.0	0.0	0.0	1.0
Spotted tentiform leafminer	3.0	0.0	0.0	0.0	0.0	0.0
Dogwood borer	0.0	8.0	36.0	25.0	37.0	67.0
Peachtree borer	0.0	0.0	0.0	0.0	0.0	5.0
Lesser peachtree borer	65.0	63.0	66.0	30.0	38.0	40.0
San Jose scale	0.0	0.0	0.0	0.0	2.5	0.0
*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.

2026 Degree Days - MHCRS (Mills River)

	Accumulated Degree Days
Insect	May 4	May 11	May 18
Codling moth (Biofix Apr 11)	247	317	397
Oriental fruit moth (Biofix Mar 21)	620	718	829
Tufted apple bud moth (Biofix Apr 17)	219	318	428

About degree-day models

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.