WNC Orchard Insect Pest Populations – July 13, 2021
2nd Generation Codling Moth Remains Key Pest
In orchards with elevation of about 2000 ft or greater (e.g., Henderson, Haywood, Wilkes, etc.) we are approaching the optimum time for an insecticide targeting second-generation codling moth. Degree-day accumulations in Henderson County are about 1370 as of July 13, and 1400 DD will occur later this week. In most cases a single application is sufficient for most orchards, the exception being where high populations exist – this is most easily based on pheromone trap captures >5 moths per week, or the presence of at least 0.5% damaged fruit up to this point in time.
As mentioned in previous posts, insecticides targeting second-generation codling moth are usually not necessary where using mating disruption is being used.
In lower elevations such as Cleveland and Lincoln County, DD accumulations average about 1850, which means the majority of second-generation adults have emerged and egg hatch is about 65% complete. The need for additional insecticides targeting this generation are probably not necessary in most orchards, again the exception being in orchards with high populations.
Brown Marmorated Stink Bug: BMSB degree-day accumulations range from about 450 in higher elevations (≥2000 ft) to 675 DD at 1000 ft. Initial emergence of first-generation adults begins at about 750 DD, with insecticides recommended at 800 DD, which will occur in lower elevation orchards the latter part of next week (July 22-24). We are still several weeks away from emergence at elevations of 1500 ft or higher.
Learn more about southeastern apple insect pests at the Apple Insect Management page.
2021 Average Weekly Trap Captures
|Insects per trap|
|Jun 28||Jul 6||Jul 13|
|Oriental fruit moth||36.0||33.5||22.0|
|Tufted apple bud moth||1.0||0.0||0.0|
|Apple maggot (abandoned and research orchards)||0.0||0.0||0.0|
|Brown marmorated stink bug (commercial)||1.7||2.8||1.9|
|Brown marmorated stink bug (unsprayed)||4.0||4.0||0.5|
|Spotted tentiform leafminer||27.0||13.0||4.0|
|Lesser peachtree borer||25.0||29.0||14.0|
|San Jose scale||2.5||0.0||5.0|
*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
|Jun 28||Jul 6||Jul 13|
|Codling moth (Biofix: April 10)
|Oriental fruit moth (Biofix: March 27)
|Tufted apple bud moth (Biofix: April 30)
2021 Pest Trends (click to enlarge)
Visit WNC Orchard Insect Populations for archived posts.