WNC Orchard Insect Pest Populations – May 3, 2023

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Rosy apple aphids in apple leafCodling moth is the main pest of concern at this time. With biofix dates of April 1st and 7th in Cleveland and Henderson Counties, respectively, a total of about 145 and 300 degree-days have accumulated thus far. The codling moth egg-hatch model predicts initial egg hatch to occur at 250 DD after biofix. Hence, insecticides may be necessary in lower elevation orchards (about 1,000 ft elevation) at this time. Egg hatch in Henderson County (about 2100 ft elevation) is not expected to begin for another 7 to 10 days.

In orchards using mating disruption, it is unlikely that insecticides will be necessary for first generation codling moth. However, pheromone traps should be used to confirm that supplemental insecticides are not required. Unless there is a cumulative trap capture of >3 moths over a two week period, insecticides are not recommended for codling moth.

If needed, there is still time to apply an insecticide targeting San Jose scale crawlers. First cover is generally the time when crawler emergence begins in earnest, so preventive control should be applied no later than first cover. Esteem, Centaur, Movento and Assail all provide good control, but from a resistance management perspective, avoid using the same material twice in the same year, and if possible rotate materials among years as well.

Rosy apple aphid populations have been fairly high in certain areas this year. RAA populations tend to naturally decline with warmer temperatures, so the cool weather we are experiencing tends to prolong the infestation period of this insect. Before spraying specifically for this insect, unravel curled leaves to confirm the presence of live aphids. There are many insecticides with excellent activity against RAA, including Admire Pro (and generics), Actara, Assail, Beleaf, Closer, Sivanto Prime, and Movento.

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

2023 Average Weekly Trap Captures

Insects per trap
Apr 17 Apr 24 May 1
Codling moth  2.0 8.0 0.5
Oriental fruit moth 67.5 89.5 26.0
Tufted apple bud moth 0.0 19.0 9.0
Redbanded leafroller 4.0 4.0 0.0
Obliquebanded leafroller
Lesser appleworm
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial)
Brown marmorated stink bug (unsprayed) 0.0 1.5 0.0
Spotted tentiform leafminer 0.0 0.0 0.0
Dogwood borer 0.0 0.0 1.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 20.0 45.0 7.0
San Jose scale 0.0 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.

2023 Accumulated Degree Days

Apr 17 Apr 24 May 1
Codling moth (Biofix: April 7) 72 130 170
Oriental fruit moth (Biofix: March 24) 285 366 433
Tufted apple bud moth (Biofix: April 21) 80

About degree-day models

2023 Pest Population Trends

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