WNC Orchard Insect Pest Populations – May 18, 2021

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Periodical cicada on apple treeMay 18, 2021

Codling moth remains the primary concern across the region, with degree-day accumulations since biofix ranging from about 300 DD in Henderson County to about 520 in the Cleveland/Lincoln County area. As highlighted in last week’s update, insecticide recommendations vary depending on how an orchard is being managed – i.e., a full crop versus one that is questionable as to whether or not to manage.

In higher elevations (Henderson, Haywood, Wilkes) being managed as a full crop, insecticidal control of codling moth is recommended an upcoming spray. In situations with a low codling moth population and which have not yet been sprayed for codling moth, an application should be made at about 350 DD, which is later this week in these locations. In lower elevations where DD accumulations are about 520, it should be remembered that an application between 500 and 650 DD will coincide the optimum timing for control of tufted apple bud moth. While first generation codling moth can remain a concern up to about 900 DD, in most situations insecticides are not needed beyond 600 and 650 DD.

In orchards with a low crop load that do not justify a normal spray program, it would be wise to make a single insecticide application between 500 and 650 DD to target both codling moth and TABM.

Brood X of 17-year Cicada: There have been numerous stories in the press about emergence of Brood X of the 17-year cicada. Within our region, this brood is expected to be restricted to northeast Georgia and far western North Carolina in Cherokee County, and should not be a concern for growers in other areas. Female cicadas lay eggs with a sharp ovipositor in the limbs of trees, and in large numbers they can do considerable damage to fruit trees. Most pyrethroids and neonicotinoids will control cicadas, but frequency of application will vary with the intensity of populations.


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


2021 Average Weekly Trap Captures

HENDERSON COUNTY
Insects per trap
May 3 May 10 May 17
Codling moth  15.5 4.5 2.5
Oriental fruit moth 11.5 11.5 3.0
Tufted apple bud moth 5.0 2.0 10.0
Redbanded leafroller 4.0 0.0 0.0
Obliquebanded leafroller 0.0 0.0 0.0
Lesser appleworm 0.0 0.0 0.0
Apple maggot (abandoned and research orchards)
Brown marmorated stink bug (commercial) 1.0
Brown marmorated stink bug (unsprayed) 0.5 1.0 0.5
Spotted tentiform leafminer 2.0 0.0 0.0
Dogwood borer 0.0 1.0 10.0
Peachtree borer 0.0 0.0 0.0
Lesser peachtree borer 42.0 29.0 33.0
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.


2021 Accumulated Degree Days

HENDERSON COUNTY
May 3 May 10 May 17
Codling moth (Biofix: April 10)
177 243 298
Oriental fruit moth (Biofix: March 27)
372 467 550
Tufted apple bud moth (Biofix: April 30)
32 108 191

About degree-day models


2021 Pest Trends (click to enlarge)

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


Visit WNC Orchard Insect Populations for archived posts.


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