WNC Orchard Insect Pest Populations – June 15, 2021
Codling moth model DD accumulations range from about 810 in Henderson County to about 1150 in Cleveland County. These values coincide with >95% emergence of first generation moths in Henderson County to completion of first generation flight in lower elevations. Except for those orchards with high populations and where there is little drop in pheromone trap captures, insecticidal control of this pest should not be necessary until about 1400 DD, or when second generation egg hatch begins.
Where tufted apple bud moth is a concern, the window of opportunity to apply an insecticide for season-long control remains open. For growers who have not applied an insecticide effective against TABM in the past 3 weeks, an application should be considered.
For those wondering about the status of brown marmorated stink bug, overwintered adults have completed emergence and are now laying eggs. Based on degree-model predictions, first generation egg laying is approximately 30%, 40% and 60% complete in Henderson, Wilkes and Cleveland Counties, respectively. Some of these eggs have hatched and small to medium sized nymphs are present. While most eggs are laid on wild hosts adjacent to orchards, egg laying can sometimes occur within orchards, especially on peaches. Also, migration of nymphs from wild hosts onto orchard trees adjacent to woods is also possible. Control of nymphs is generally easier than adults, and most neonicotinoids, including imidacloprid, will control these individuals. Emergence of the more damaging F1 adult generation is not expected for at least another 4 weeks (at less than 1000 ft elevation) to 8 weeks (at >2000 ft elevation).
Learn more about southeastern apple insect pests at the Apple Insect Management page.
2021 Average Weekly Trap Captures
|Insects per trap|
|Jun 1||Jun 7||Jun 14|
|Oriental fruit moth||6.0||13.0||17.0|
|Tufted apple bud moth||28.0||14.0||2.0|
|Apple maggot (abandoned and research orchards)||0.5||0.0||0.0|
|Brown marmorated stink bug (commercial)||1.7||1.8||1.0|
|Brown marmorated stink bug (unsprayed)||0.5||1.5||7.5|
|Spotted tentiform leafminer||3.0||0.0||20.0|
|Lesser peachtree borer||48.0||51.0||52.0|
|San Jose scale||0.0||5.0||0.0|
*Note that these averages illustrate only the timing of insect emergence and fluctuations in populations, and are not representative of population levels in any given orchard. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.
2021 Accumulated Degree Days
|Jun 1||Jun 7||Jun 14|
|Codling moth (Biofix: April 10)
|Oriental fruit moth (Biofix: March 27)
|Tufted apple bud moth (Biofix: April 30)
2021 Pest Trends (click to enlarge)
Visit WNC Orchard Insect Populations for archived posts.