WNC Orchard Insect Populations for June 26, 2018

— Written By and last updated by

June 26, 2018Green apple aphids on apple leaf

Little has changed since last week in higher elevation orchards such as Henderson County (>2000 ft). At about 1100 DD from biofix, we remain between flights of the first and second codling moth generations. In addition, oriental fruit moth populations remain low throughout the area, and first generation tufted apple bud moth flight is complete. European red mite, leafhoppers and aphids remain the key potential pests at this time.

In lower elevation orchards such as Cleveland and Lincoln Counties, second generation codling moths are beginning to emerge. Codling moth DD accumulations since biofix in Cleveland County is about 1380, and first sprays for second generation flight are recommended at 1400 to 1450, depending on codling moth pressure. In orchards with low pheromone trap captures and no damage from the first generation, a single application shortly after 1500 DD is usually sufficient.

Now is a good time to keep an eye out for Japanese beetles, especially on young trees, as high numbers of them have been noted in some locations. Most neonicotinoids will do a good job knocking down Japanese beetle numbers without flaring European red mite populations.

Brown marmorated stink bug populations remain low throughout the region. Currently, overwintered adults are declining in numbers and nymphs are in early stages of development – second or third instars.


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


2018 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
June 11
June 18
June 25
Codling Moth 0.8 1.0 0.5
Oriental Fruit Moth 16.0 15.7 19.3
Tufted Apple Bud Moth 1.0 1.0 0.0
Redbanded Leafroller 0.0 0.0 0.0
Obliquebanded Leafroller 0.0 0.0 2.0
Lesser Appleworm 0.0 0.0 0.0
Apple Maggot 0.0 0.0 0.3
Brown Marmorated Stink Bug (commercial – mountains) 1.5 0.5 0.4
Brown Marmorated Stink Bug (commercial – upper piedmont) 0.7 1.0 0.6
Brown Marmorated Stink Bug (research – unsprayed) 2.5 2.3 0.8
Spotted Tentiform Leafminer 40.0 12.0 30.0
Dogwood Borer 18.0 18.0 48.0
Peachtree Borer 16.0 22.0 28.0
Lesser Peachtree Borer 42.5 15.0 13.5
San Jose Scale 7.5 12.5 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 June 11
June 18
June 25
Codling Moth Apr 30 797 936 1124
Oriental Fruit Moth Apr 2 1249 1418 1636
Tufted Apple Bud Moth May 4 929 1099 1317
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.

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.