WNC Orchard Insect Pest Populations – April 22, 2024

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Petal Fall Sprays and Upcoming Insect Pests:

apple orchard

The cool weather this week has slowed development and activity of key pests targeted at petal fall. This will expand the window for optimum timing of applications until this weekend or early next week.

Target pests at petal fall include plum curculio, oriental fruit moth (OFM) and, if not controlled before bloom, rosy apple aphid. If mating disruption for codling moth and OFM was deployed before OFM started to fly about the third week of March, insecticidal control may not be necessary. The relative efficacy of insecticides recommended at petal fall are shown in the table below. Note that all insecticides recommended at bloom are toxic to bees, so delay petal fall sprays on those cultivars still in heavy bloom, most likely Romes.

Looking ahead over the next couple of weeks, pests to plan for include San Jose scale between petal fall and first cover, preventive control of European red mite and codling moth.

Relative Efficacy of Insecticides for Petal Fall

( ─ no activity, 1 = least effective, 5 = most effective)

Insecticide (active


Plum Curculio

Oriental Fruit Moth

Rosy Apple Aphid

Toxicity to Bees

Actara (thiamethoxam) 5 2 5 Highly Toxic
Assail (acetamiprid) 3 4 5 Moderately Toxic
Belay (chlothianidin) 4 3 5 Highly Toxic
Avaunt (Indoxacarb) 4 4 Highly Toxic
Imidan (phosmet) 4 4 Highly Toxic
Verdepryn (cyclaniliprole) 4 5 Highly Toxic
Sevin (carbaryl) 3 3 Highly Toxic
Voliam Flexi
(thiamethoxam +
5 5 5 Highly Toxic

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

2024 Average Weekly Trap Captures

Insects per trap
Apr 8 Apr 15 Apr 22
Codling moth  0.0 0.5 4.5
Oriental fruit moth 108.5 103.0 60.0
Tufted apple bud moth 0.0 2.0 3.0
Redbanded leafroller 2.0 2.0 4.0
Obliquebanded leafroller setup 0.0 0.0
Lesser appleworm setup 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) setup 1.0 0.7
Brown marmorated stink bug (unsprayed) setup 0.0 0.0
Spotted tentiform leafminer 2.0 2.0 2.0
Dogwood borer 0.0 0.0 0.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 0.0 3.0 4.0
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.

2024 Accumulated Degree Days

Apr 8 Apr 15 Apr 22
Codling moth (Biofix: April 15) biofix 77
Oriental fruit moth (Biofix: March 15) 188 288 401
Tufted apple bud moth (Biofix: April 15) biofix 107

About degree-day models

2024 Pest Population Trends

graph showing insect populations graph showing insect populations graph showing insect populations graph showing insect populations graph showing insect populations graph showing insect populations graph showing insect populations