WNC Orchard Insect Pest Populations – August 3, 2021

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Codling Moth Threat Declines, Stink Bug Populations on the Rise

Apple orchard and mountainsCodling moth: Second generation flight of the codling moth is complete or nearly complete in all regions except for elevations >2500 ft. In lower elevation orchards (less than about 1200 ft), third generation adult emergence will begin this weekend based on degree-day predictions. However, if populations have not been problematic up to this point in time, it is highly doubtful that problems would arise this late in the year.

Brown Marmorated Stink Bug:  Based on DD accumulations at three different production sites (Cleveland, Henderson and Wilkes Counties), emergence of first generation adults is about 40% complete in the lower elevation of Cleveland County (see graph below) and is just beginning in Wilkes County. Now is an important time for insecticidal control of BMSB in orchards at elevations 1500 ft and lower. Emergence in Henderson County is predicted to begin on 13 August. See the 20 July update for BMSB insecticide recommendations.Graph of stink bug population growth

Apple Maggot:  We have still not observed apple maggot flies on traps in our abandoned orchard in Henderson County. While this is a little late for emergence to not yet have begun, it is not entirely unusual. However, emergence can vary among locations, so trapping in individual orchards is encouraged.


Learn more about southeastern apple insect pests at the Apple Insect Management page.


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 19 Jul 26 Aug 2
Codling moth  0.5 1.5 2.0
Oriental fruit moth 28.0 18.0 19.5
Tufted apple bud moth 0.0 1.0 1.0
Redbanded leafroller 0.0 0.0 4.0
Obliquebanded leafroller 0.0 3.0 2.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.0 0.0
Brown marmorated stink bug (commercial) 5.5 7.0 3.0
Brown marmorated stink bug (unsprayed) 2.1 5.0 3.4
Spotted tentiform leafminer 5.0 2.0 4.0
Dogwood borer 21.0 24.0 21.0
Peachtree borer 19.0 27.0 32.0
Lesser peachtree borer 17.0 13.0 9.0
San Jose scale 5.0 0.0 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

HENDERSON COUNTY
Jul 19 Jul 26 Aug 2
Codling moth (Biofix: April 10)
1512 1678 1858
Oriental fruit moth (Biofix: March 27)
2057 2279 2491
Tufted apple bud moth (Biofix: April 30)
1860 1920 2132

About degree-day models


2021 Pest Trends (click to enlarge)

Chart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trendsChart showing insect population trends


Visit WNC Orchard Insect Populations for archived posts.


Additional Resources