WNC Orchard Insect Pest Populations – August 25, 2020

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— Written By Jim Walgenbach (4 weeks ago) and last updated by Stephen Schoof

In keeping with the theme of the past several weeks, insects of greatest concern at this time are brown marmorated stink bug (BMSB) and oriental fruit moth (OFM).

Emergence of first-generation BMSB adults continues throughout the region. Based on model predictions, emergence is just beginning in higher elevations such as Haywood County, and is almost 75% complete in lower elevations such as Lincoln/Cleveland County.

Brown Marmorated Stink Bug

Based on pheromone trap captures to date, BMSB populations this year appear to be lower than last year at this time. This is illustrated in the figure below, which shows average BMSB pheromone trap captures in the same six locations over the past 3 years. While it is a little early to make predictions on the size of this year’s population, population densities appear to be similar to 2018 as opposed to 2019. We will continue to provide updates on populations over the coming weeks.

Oriental Fruit Moth

As is typical for this time of the year, OFM pheromone trap captures have continued to increase in several locations. Where pyrethroids are being applied for BMSB, OFM should not be a problem, because these insecticides are quite effective against this pest. Where BMSB populations are low and insecticidal control is not warranted, it would be wise to keep an eye on OFM. Where mating disruption has been used, it is highly unlikely that OFM populations are problematic.

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

2020 Average Weekly Trap Captures

HENDERSON COUNTY
	Insects per trap
	Aug 10	Aug 17	Aug 24
Codling moth	0.6	0.5	0.0
Oriental fruit moth	3.6	4.3	6.7
Tufted apple bud moth	5.5	5.0	5.0
Redbanded leafroller	0.0	0.0	0.0
Obliquebanded leafroller	0.0	0.0	0.0
Lesser appleworm	0.0	0.0	2.0
Apple maggot (abandoned and research orchards)	1.7	1.0	1.7
Brown marmorated stink bug (commercial)	3.2	3.1	2.4
Brown marmorated stink bug (unsprayed)	2.8	7.0	11.3
Spotted tentiform leafminer	0.0	2.0	0.0
Dogwood borer	7.0	17.0	20.0
Peachtree borer	29.0	18.0	30.0
Lesser peachtree borer	22.0	13.0	40.0
San Jose scale	17.5	117.5	260.0

*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
	Aug 10	Aug 17	Aug 24
Codling moth (Biofix 4/20)	1917 DD	2095 DD	2216 DD
Oriental fruit moth (Biofix 3/30)	2625 DD	2843 DD	2994 DD
Tufted apple bud moth (Biofix 4/27)	2367 DD	2585 DD	2736 DD