Current Western NC Orchard Pest Populations, July 27 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.
JULY 27, 2015
With the exception of brown marmorated stink bug, overall insect pressure remains low on apples and peaches in the mountains and western piedmont regions of NC.
Codling Moth: In Henderson County, degree-day accumulations since biofix averaged about 1850. This is a period of time when second generation flight is almost complete, but when the potential for egg laying remains a threat in orchards with existing populations. In fact, we did observe an increase in pheromone trap captures in several minimal or non-sprayed orchards during the past week. However, the vast majority of commercial orchards have no evidence of damage and low pheromone trap captures, and decisions about insecticide sprays should be based on pheromone trap captures in individual orchards.
In the piedmont region (Cleveland County), degree-day accumulations since biofix average almost 2500. Decisions regarding the need for insecticide sprays should be based solely on pheromone trap captures, because the model does not accurately predict third generation activity. Pheromone trap captures that average more than 5 moths/trap per week are an indication that a damaging population may exist.
Oriental Fruit Moth: Although this is a time of the year when OFM populations often increase, we have yet not observed increased captures in pheromone traps in our sampling orchards. Despite low populations and very little evidence of damage in either apple or peach orchards, pheromone trapping is especially important in orchards not using mating disruption.
Apple Maggot: To date, evidence suggests that this may be a low-pressure apple maggot year. Peak trap capture is usually around this time of the year, but trap captures in our non-sprayed orchards remain very low.
Brown Marmorated Stink Bug: In the piedmont counties, there are large numbers of first generation adults emerging from wooded areas and infesting adjacent tree fruits and vegetables. These adults are laying eggs and are expected to continue laying eggs at least through the first week of August. Hence, both adult and nymphs will be potential pests for the next 4 to 6 weeks. In higher elevations, such as Buncombe and Henderson county, first generation adults are emerging, but they are just now beginning to lay eggs. The majority of nymphs currently observed are from those eggs laid by overwintered adults.
In crops with BMSB problems, most pyrethroids and several neonicotinoid insecticides provide good control, but frequent application intervals may be necessary under high pressure conditions. Pyrethroids are particularly harmful to biological control programs in pome fruits, so it is important to verify a BMSB problem before initiating a spray program. The following insecticides are recommended for apples and peaches:
|*Bifenthrin||Brigade, Bifenture, Sniper||14||14|
|Lambda-cyhalothrin||Warrior, Karate, LambdaCy||21||14|
|Lambda-cyhalothrin + Thiamethoxam||Endigo||14||14|
|*Bifenthrin and dinotefuran are approved for use in NC under a Section 18 label that expires on 10-15-2015.|
Average Weekly Trap Captures*
|Insects per trap|
|Oriental Fruit Moth
|Tufted Apple Bud Moth||0.5||1.5||2.0|
|Brown Marmorated Stink Bug||20.5||0.3||0.0|
|Spotted Tentiform Leafminer||0.0||0.0||0.0|
|Lesser Peachtree Borer||20.0||21.0||7.0|
|San Jose Scale||10005.0||1697.5||2015.0|
*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.
Accumulated Degree Days
|Codling Moth||April 23||1480||1662||1840|
|Oriental Fruit Moth||Apr 6||2098||2315||2518|
|Tufted Apple Bud Moth||April 23||1839||2055||2258|
|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: