WNC Orchard Insect Populations for July 23, 2018
Based on degree-day accumulations and pheromone trap captures in non-managed orchards, codling moth and oriental fruit moth both remain active in the mountains (Henderson County), but populations appear to be low in many managed orchards. In most situations, a single insecticide application targeting codling moth will likely be sufficient, but all decisions should be based on trap captures in individual orchards.
As noted last week, first generation brown marmorated stink bug (BMSB) adults are active in lower elevation orchards including Burke, Lincoln, and Cleveland Counties. In those orchards with a history of BMSB damage, insecticide sprays should be applied at this time. This would include products containing pyrethroids or Venom/Scorpion.
In higher elevation orchards (e.g., Henderson County), the BMSB degree-day development model is predicting first generation adults to begin emerging later this week. In fact there was a slight uptick in pheromone trap captures this week, suggesting some emergence has started. To avoid damage on the most susceptible cultivars, insecticides targeting BMSB should begin at your next sprays.
Finally, there was large emergence of apple maggot in our abandoned site in Henderson County this week, with 23 flies captured. Apple maggot emergence times can vary considerably within a region due to microclimate effects, but for those growers not trapping and unsure of maggot activity in their orchards, an insecticide effective against this pest should be made at this time. Pyrethroids applied for BMSB will also provide protection against apple maggot. If not applying a pyrethroid for BMSB, imidacloprid (Admire or generic products) will control apple maggot.
Learn more about southeastern apple insect pests at the Apple Insect Management page.
2018 Average Weekly Trap Captures*
|Insects per trap|
|Oriental Fruit Moth||11.0||34.0||23.0|
|Tufted Apple Bud Moth||0.0||1.0||6.0|
|Brown Marmorated Stink Bug (commercial – mountains)||0.2||0.5||0.7|
|Brown Marmorated Stink Bug (commercial – upper piedmont)||2.2||4.3||2.8|
|Brown Marmorated Stink Bug (research – unsprayed)||0.8||0.8||0.5|
|Spotted Tentiform Leafminer||0.0||0.0||14.0|
|Lesser Peachtree Borer||4.0||13.0||10.0|
|San Jose Scale||17.5||70.0||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
|Codling Moth||Apr 30||1488||1661||1819|
|Oriental Fruit Moth||Apr 2||2071||2280||2473|
|Tufted Apple Bud Moth||May 4||1752||1960||2154|
|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.|
ORIENTAL FRUIT MOTH:
TUFTED APPLE BUD MOTH: