WNC Orchard Insect Populations for May 15, 2018
We are approaching the time when insecticides for first generation codling moth will need to be initiated. Degree-day accumulations since biofix range from about 200 in Henderson County to 320 off the mountain in Cleveland County. In situations where moderate to high populations exist (i.e., probably observed some damage in 2017), the first spray should be applied at 250 DD. In orchards with low populations (low trap captures and no damage in 2017), the first application can be delayed until about 350 DD, which is predicted to occur next week in Henderson County. In orchards using mating disruption, it is highly unlikely that insecticides for lepidopteran pests (e.g., tufted apple bud moth, codling moth) will be needed until early to mid-June, although pheromone trap captures should be used to mitigate the unexpected. The cooler and rainy weather predicted for the coming days will help to reduce codling moth flight and egg laying.
For those planning to control San Jose scale post bloom with Esteem, Centaur or Movento applications, sprays should be made by the end of this week for best results.
Finally, emergence of overwintering brown marmorated stink bug adults is about two-thirds complete in Henderson County, with emergence expected to be completed in the next two weeks. Emergence is complete off the mountain in lower-elevation orchards. To date, numbers have been fairly low in pheromone traps.
Learn more about southeastern apple insect pests at the Apple Insect Management page.
2018 Average Weekly Trap Captures*
|Insects per trap|
|Oriental Fruit Moth||38.0||16.0||6.7|
|Tufted Apple Bud Moth||0.0||13.0||6.0|
|Brown Marmorated Stink Bug (commercial – mountains)||0.0||0.0||n/a|
|Brown Marmorated Stink Bug (commercial – upper piedmont)||1.3||1.3||n/a|
|Brown Marmorated Stink Bug (research – unsprayed)||0.3||2.3||0.5|
|Spotted Tentiform Leafminer||0.0||0.0||0.0|
|Lesser Peachtree Borer||13.0||139.0||98.0|
|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
|Codling Moth||Apr 30||–||93||196|
|Oriental Fruit Moth||Apr 2||247||372||503|
|Tufted Apple Bud Moth||May 4||–||52||184|
|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: