WNC Orchard Insect Populations for July 3, 2018

— Written By and last updated by

picture of apple orchard edgeJuly 3, 2018

Depending on location, codling moth degree-day accumulations since biofix range from about 1300 in Henderson County to almost 1600 in Lincoln County. Timing of first insecticide applications is recommended at about 1400 DD. Under low population densities, a single application between 1400 and 1500 DD will provide sufficient protection, while two successive applications at 14-day intervals are recommended if pheromone trap captures are exceeding 5 to 7 moths/trap or there is evidence of first-generation damage. Depending on population abundance, codling moth could be an issue for another two to three weeks.

The normal early July complex of indirect pests continue to be observed throughout the region, including Japanese beetles, European red mite, apple aphids, and potato leafhopper. In most instances a single application of a miticide for ERM and a neonicotinoid for Japanese beetles, aphids and leafhoppers has provided excellent control.

Looking ahead to the next few weeks, first-generation adult brown marmorated stink bugs are expected to begin emerging in about a week in lower elevation piedmont locations, and in about two to three weeks in higher elevation orchards (>2000 ft). Typically it is this generation of adults that can potentially cause the greatest levels of damage, particularly during the main emergence period in August. To date, BMSB numbers have been quite low throughout the region, but we have pheromone traps set up in numerous locations throughout the region. We will keep you updated on trap captures in the coming weeks.

Dinotefuran (Venom, Scorpion) and Bifenthrin (Bridage, Bifenture) Section 18 Approved for Control of Brown Marmorated Stink Bug

The EPA has approved the NCDA&CS request for Section 18 emergency use exemptions of the active ingredients dinotefutran and bifenthrin on apples and peaches to control brown marmorated stink bug. Dinotefuran products available for use include Venom (Valent USA) and Scorpion (Gowan Company), while bifenthrin products include Brigade (FMC Corp.) and Bifenture (United Phosphorus, Inc.). This is a regional Section 18 approval for these materials that includes most of the tree fruit production states in the eastern US. Dinotefuran has a 3-day PHI, and a maximum of only two applications per season (Venom and/or Scorpion) may be applied. Product labels must be on hand when using these products, and can be downloaded below:

Venom

Scorpion 

Brigade

Bifenture


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


2018 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
June 18
June 25
July 2
Codling Moth 1.0 0.5 0.3
Oriental Fruit Moth 15.7 19.3 15.7
Tufted Apple Bud Moth 1.0 0.0 0.0
Redbanded Leafroller 0.0 0.0 0.0
Obliquebanded Leafroller 0.0 2.0 0.0
Lesser Appleworm 0.0 0.0 0.0
Apple Maggot 0.0 0.3 0.0
Brown Marmorated Stink Bug (commercial – mountains) 0.5 0.4 0.3
Brown Marmorated Stink Bug (commercial – upper piedmont) 1.0 0.6 1.3
Brown Marmorated Stink Bug (research – unsprayed) 2.3 0.8 1.0
Spotted Tentiform Leafminer 12.0 30.0 0.0
Dogwood Borer 18.0 48.0 20.0
Peachtree Borer 22.0 28.0 30.0
Lesser Peachtree Borer 15.0 13.5 7.0
San Jose Scale 12.5 0.0 2.5

*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 June 18
June 25
July 3
Codling Moth Apr 30 936 1124 1323
Oriental Fruit Moth Apr 2 1418 1636 1876
Tufted Apple Bud Moth May 4 1099 1317 1556
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 trend graph Oriental fruit moth trend graph tufted apple bud moth trend graph redbanded leafroller trend graph lesser appleworm trend graph obliquebanded leafroller trend graph spotted tentiform leafminer trend graph dogwood borer trend graph peachtree borer trend graph lesser peachtree borer trend graph apple maggot trend graph brown marmorated stink bug trend graph san jose scale trend graph