Current Western NC Orchard Pest Populations Aug 17, 2015
We track local insect populations throughout the growing season using a system of traps, temperature-recording devices, and degree-day models. Traps and weather data are checked weekly, with results updated by Tuesday afternoon from April through September. Learn more about southeastern apple pests at the Apple Pest Management page.
August 17, 2015
Both codling moth and oriental fruit moth pheromone trap captures declined sharply during the past week.
Codling Moth. Based on degree-day accumulations, the drop in codling moth captures coincides with what is normally the tail end of the second generation flight. This probably represents the end of codling moth activity in Henderson County and elsewhere with similar elevations. While third generation moths cannot be discounted in piedmont locations, this would very likely occur only where damage from previous generations was evident.
Oriental Fruit Moth. Surprisingly, OFM trap captures also declined during the past week. However, a dip in trap captures in mid to late August is not uncommon and may represent separation of the third and fourth generation. As mentioned in posts in previous weeks, sprayable pheromone is probably the most effective approach to managing late-season OFM. In most situations an application in mid to late August will often provide control through September.
Apple Maggot. Trap captures in abandoned orchards remained steady at about 10 flies per trap. In most commercial orchards, apple maggot is of greatest concern during the first week or two of enhanced activity in abandoned orchards. Movement of flies from abandoned to commercial orchards often declines in late August and early September. There is usually no need for more than one or two insecticide applications targeting apple maggot.
Brown Marmorated Stink Bug. The number of adults captured in traps and observed in surveys has appeared to level off or actually decline. This is generally a time when adult numbers begin to rapidly increase in advance of peak densities in early September. Hopefully this lower-than-expected adult population is real and not an aberration.
Average Weekly Trap Captures*
|Insects per trap|
|Oriental Fruit Moth
|Tufted Apple Bud Moth||3.5||3.0||5.0|
|Brown Marmorated Stink Bug||0.0||0.5||0.5|
|Spotted Tentiform Leafminer||18.0||18.0||8.0|
|Lesser Peachtree Borer||25.0||28.5||57.0|
|San Jose Scale||367.5||325.0||512.5|
*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.
Accumulated Degree Days
|Codling Moth||April 23||2014||2184||2331|
|Oriental Fruit Moth||Apr 6||2734||2936||3116|
|Tufted Apple Bud Moth||April 23||2474||2676||2856|
|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: