WNC Orchard Insect Populations for August 7, 2018
Overall, insect populations are fairly low at this time, which is probably in part due to the heavy rains. Second generation codling moth flight is complete and trap captures are low throughout the region. While OFM populations can increase during the next several weeks, those numbers have also been quite low to date.
The two main insects of concern remain brown marmorated stink bug and apple maggot. First generation adult BMSB will continue to emerge over the next several weeks, but to date numbers have been fairly low. Apple maggot captures have been high for the past three weeks, and orchards near abandoned sites are at greatest risk. In those orchards where apple maggot is a potential concern, particularly with ‘Golden Delicious,’ and pyrethroids are not being applied for BMSB, imidacloprid should be considered.
In areas with heavy hail damage and where apples are destined for processing or juice, some thought should go into whether or not it is economically wise to apply pyrethroids for BMSB control. These apples already have damage similar to stink bug, and it is doubtful that spraying for BMSB will increase the value of the fruit. In addition, avoiding pyrethroid applications this year should help natural enemy populations return to pre-2017 levels, and reduce the potential for European red mite, woolly apple, and San Jose scale outbreaks next year. Just some food for thought.
Learn more about southeastern apple insect pests at the Apple Insect Management page.
2018 Average Weekly Trap Captures*
|Insects per trap|
|Oriental Fruit Moth||23.0||17.7||13.0|
|Tufted Apple Bud Moth||6.0||3.0||1.0|
|Apple Maggot (abandoned and research)||7.7||19.3||21.3|
|Brown Marmorated Stink Bug (commercial – mountains)||0.7||0.8||1.0|
|Brown Marmorated Stink Bug (commercial – upper piedmont)||2.8||2.2||1.8|
|Brown Marmorated Stink Bug (research – unsprayed)||0.5||1.8||1.3|
|Spotted Tentiform Leafminer||14.0||5.0||3.0|
|Lesser Peachtree Borer||10.0||10.5||10.5|
|San Jose Scale||0.0||2.5||5.0|
*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||1819||1950||2100|
|Oriental Fruit Moth||Apr 2||2473||2633||2819|
|Tufted Apple Bud Moth||May 4||2154||2314||2500|
|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: