WNC Orchard Insect Pest Populations – June 30, 2020

— Written By and last updated by

ApplesThroughout most of the higher elevation orchards (≥2000 ft), we are still in that period of low potential for insect damage. Codling moth degree-day accumulations are only at about 940 as of June 30, indicating first generation flight is complete and second generation flight is still a few weeks off. Also, OFM populations remain low in most orchards. The most common insects are secondary pests such as aphids, leafhoppers and mites, all of which can be managed with curative insecticide/miticide applications. Monitoring for these pests over the next few weeks should be conducted to determine the need for insecticides.

In lower elevation orchards, such as Lincoln and Cleveland Counties and other locations ≤1000 ft, second generation codling moth flight is just beginning. Cumulative codling moth DDs in this area are about 1400 DD, and insecticides are recommended at about 1450 DD when populations are of moderate to high density. Where populations are low – no damage by the first generation and low pheromone trap captures (no more than 1 or 2 moths per week) – insecticide applications can be delayed to 1550-1600 DD, or not applied if trap captures remain very low.

In orchards using mating disruption for codling moth and OFM, insecticides targeting second generation are rarely needed, although pheromone trap monitoring should be used to verify the absence of moths.


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


2020 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
Jun 15 Jun 22 Jun 29
Codling moth  0.3 0.0 0.7
Oriental fruit moth 2.6 1.6 1.0
Tufted apple bud moth 23.0 2.0 4.0
Redbanded leafroller 0.0 0.0 0.0
Obliquebanded leafroller 14.0 2.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards) 0.0 0.0 0.7
Brown marmorated stink bug (commercial) 1.1 0.8 1.5
Brown marmorated stink bug (unsprayed) 4.3 1.5 1.9
Spotted tentiform leafminer 0.0 24.0 31.0
Dogwood borer 36.0 9.0 14.0
Peachtree borer 3.0 5.0 9.0
Lesser peachtree borer 54.0 41.0 33.0
San Jose scale 0.0 2.5 190.0

*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
Jun 15 Jun 22 Jun 29
Codling moth (Biofix 4/20) 678 DD 778 DD 919 DD
Oriental fruit moth (Biofix 3/30) 1111 DD 1246 DD 1421 DD
Tufted apple bud moth (Biofix 4/27) 853 DD 988 DD 1163 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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