WNC Orchard Insect Populations for August 28, 2018

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August 28, 2018apple bins in orchard

With the exception of brown marmorated stink bug, insect populations are low throughout the region. Codling moth and OFM populations remain low in the vast majority of sites we’re monitoring, and apple maggot trap captures declined drastically during the past week.

BMSB does remain a potential threat to late-maturing fresh market apples. This is of greatest concern in higher elevations (>1500 ft) where first-generation BMSB adults are still emerging. An insecticide application should be considered over the next week or so on fresh market culivars that won’t be harvested until after mid-September.


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


2018 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
August 13
August 20
August 27
Codling Moth 0.5 0.5 0.0
Oriental Fruit Moth 17.0 25.7 29.0
Tufted Apple Bud Moth 0.0 0.0 0.0
Redbanded Leafroller 0.0 0.0 1.0
Obliquebanded Leafroller 0.0 0.0 1.0
Lesser Appleworm 0.0 2.0 0.0
Apple Maggot (abandoned and research) 14.3 24.5 4.0
Brown Marmorated Stink Bug (commercial – mountains) 1.3 1.8 2.2
Brown Marmorated Stink Bug (commercial – upper piedmont) 1.1 2.4 3.3
Brown Marmorated Stink Bug (research – unsprayed) 5.2 4.8 8.4
Spotted Tentiform Leafminer 0.0 5.0 0.0
Dogwood Borer 5.0 32.0 42.0
Peachtree Borer 25.0 20.5 27.0
Lesser Peachtree Borer 3.0 12.5 37.0
San Jose Scale 2.5 67.5 212.5

*Note that averages presented here are intended only to illustrate the timing of insect emergence and fluctuations in population activity, and not as general indicators of population levels. Some orchards included in these averages have significantly higher or lower populations than most commercial orchards in the area, resulting in averages that are sometimes skewed from what is typical. The only way to have an accurate assessment of an individual orchard’s populations is to set up traps in that orchard.


2018 Accumulated Degree Days

  Henderson County
 Biofix August 14
August 21
August 28
Codling Moth Apr 30 2295 2458 2595
Oriental Fruit Moth Apr 2 3054 3251 3424
Tufted Apple Bud Moth May 4 2735 2932 3105
About degree-day models: The degree day (DD) models predict adult emergence and egg hatch of each generation. They do not predict the intensity of populations, which can be assessed by using pheromone traps. Hence, the models should be used to help gauge the time period when control is most likely needed, and pheromone traps provide information on the need for and frequency of insecticide applications. For full details, read “IPM Practices for Selected Pests” in the Orchard Management Guide.

CODLING MOTH:

  • 1st generation: Egg hatch begins at about 350 DD after biofix and is completed by 1050 DD. The most critical period for insecticidal control is from 350 to about 750 DD.
  • 2nd generation: Egg hatch of the second generation can extend from about 1300 to 2600 DD after biofix, but the most critical period for insecticidal control is 1400 to about 2500 DD.
  • 3rd generation: Adults begin to emerge at about 2500 DD after biofix, but the model is less accurate in predicting late-season populations.

ORIENTAL FRUIT MOTH:

  • 1st generation: Only one insecticide application between 400 and 500 degree days is usually necessary, as 1st generation egg-laying is usually low on apple.
  • 2nd generation: Effective 1st-generation control may eliminate the need for 2nd-generation control. If trap captures remain high, insecticides may be needed around 1100 to 1400 DD.
  • 3rd generation: Insecticide may be needed at 2200 DD after biofix.
  • 4th generation: Overlapping generations late in the season make it difficult to predict when 4th-generation egg hatch begins, but continuous egg-laying can occur from August through October. Use traps to determine the need for further insecticide applications.

 TUFTED APPLE BUD MOTH:

  • 1st generation: One well-timed insecticide application between 800 and 1200 DD after biofix will often eliminate the need for further control of TABM.
  • 2nd generation: Only if trap captures exceed 25 moths per trap by 2600 DD is an insecticide application recommended. NOTE: Insecticides targeting 2nd generation TABM are usually not necessary if 1st generation populations were successfully controlled.

2018 Pest Trends (click to enlarge)

codling moth population trend graphoriental fruit moth population trend graphtufted apple bud moth population trend graph redbanded leafroller population trend graphobliquebanded leafroller population trend graphlesser appleworm population trend graph spotted tentiform leafminer population trend graphdogwood borer population trend graph peachtree borer population trend graphlesser peachtree borer population trend graphapple maggot population trend graphbrown marorated stink bug population trend graphsan jose scale population trend graph