WNC Orchard Insect Pest Populations – July 28, 2020

— Written By and last updated by

Canada geese in apple orchardCodling moth pheromone trap captures remain low throughout the area, while oriental fruit moth captures have crept up in several locations during the past week. The only location where first-generation BMSB adult emergence is underway and remains in lower-elevation (<1000 ft) sites, although emergence is predicted to begin next week in the Wilkes County area.

Codling Moth and Oriental Fruit Moth (OFM)

Codling moth DD accumulations range from 1630 in Henderson County (2nd generation egg hatch about 35% complete) to 2250 in the Cleveland/Lincoln County region (2nd generation egg hatch is >80% complete). This is an important time to monitor for codling moth in Henderson County and other areas of similar elevation (about 2000 ft), because if populations are to appear in potentially damaging numbers, now is the likely time that will happen.

During the past week or so, OFM pheromone trap captures have increased in several locations. Although trap captures have not been excessively high, an insecticide application should be considered when numbers exceed about 10 moths per trap. In areas where a pyrethroid application was recently made for BMSB, that should also control OFM.

Brown Marmorated Stink Bug

The updated model output for emergence of first-generation BMSB predicts emergence occurring only in lower elevation orchards (<1000 ft), but emergence is predicted to begin in the Wilkes County region next week (see figure below). Emergence is considerably delayed at higher elevations such as Henderson and Haywood Counties, where adult emergence is still several weeks away.

BMSB emergence chart

Apple Maggot

We are entering that time when apple maggot flies often begin to emerge in abandoned orchards. We have not yet detected a significant emergence, suggesting that this year’s cooler weather is also delaying emergence of this pest.


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


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jul 13 Jul 20 Jul 27
Codling moth  0.5 1.0 0.7
Oriental fruit moth 3.3 2.9 4.8
Tufted apple bud moth 0.0 0.0 0.5
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 1.0 0.0 1.0
Lesser appleworm 0.0 1.0 0.0
Apple maggot (abandoned and research orchards) 0.7 1.0 0.0
Brown marmorated stink bug (commercial) 1.1 1.2 1.7
Brown marmorated stink bug (unsprayed) 1.8 4.3 3.5
Spotted tentiform leafminer 15.0 30.0 16.0
Dogwood borer 28.0 9.0 6.0
Peachtree borer 21.0 33.0 31.0
Lesser peachtree borer 35.0 33.0 28.0
San Jose scale 785.0 1172.5 265.0

*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.


2020 Accumulated Degree Days

HENDERSON COUNTY
Jul 13 Jul 20 Jul 27
Codling moth (Biofix 4/20) 1246 DD 1406 DD 1581 DD
Oriental fruit moth (Biofix 3/30) 1818 DD 2008 DD 2218 DD
Tufted apple bud moth (Biofix 4/27) 1560 DD 1750 DD 1960 DD

About degree-day models


2020 Pest Trends (click to enlarge)

Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends Graph of insect population trends


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