WNC Orchard Insect Populations for June 5, 2018

— Written By and last updated by

Image of delta trapJune 5, 2018

Codling moth degree day (DD) accumulations range from about 650 in Henderson County to 850 in Cleveland County, indicating that this pest remains a concern in higher elevations such as Henderson County and higher. At 850 DD, flight should be near complete in lower elevation orchards. Trap captures have been fairly low thus far, which is not unexpected considering the amount of rain we’ve experienced. Nonetheless, codling moth remains a threat in higher elevations, and if one is not using pheromone traps or does not know the population pressure in an orchard, one should make sure insecticide protection is provided for the next 10 to 14 days.

Tufted apple bud moth DD accumulations range from about 800 in Henderson County to 1200 in Cleveland County. If an insecticide effective against TABM has not been applied within the last week, one should be made at the next application. In areas off the mountain where TABM is a problem, we are nearing the end of optimum timing for TABM control. Remember that in addition to the main insecticides recommended for codling moth – Altacor (or Voliam Flexi) or Delegate – Intrepid is also highly effective against TABM.

Although second generation oriental fruit moth flight is beginning Henderson County and is underway in lower elevations, this generation is rarely a threat to apples, especially if the first generation was adequately controlled.

Finally, June is the month when scouting for key secondary pests should begin. Both European red mite and green apple aphids are prevalent during this time. There have been quite a few reports of European red mites in many orchards, which is obviously early for our location. Although there are many excellent miticides that can suppress populations, there are few that are effective knockdown products when populations are high – i.e., >10 adults per leaf. Probably the most effective knockdown material is Acramite, followed by Nealta and Portal. Agri-Mek can also work well in this capacity, but usually when applied closer to petal fall or first cover. Other products that have good residual activity and are ovicidal and sterilize adults include Zeal, Apollo and Savey. But these products will not provide knockdown control and work best when mite populations are low – no more than 1 or 2 adults per leaf.


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


2018 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
May 22
May 29
June 4
Codling Moth 1.8 3.5 0.3
Oriental Fruit Moth 4.3 5.7 13.0
Tufted Apple Bud Moth 12.0 12.0 11.0
Redbanded Leafroller 0.0 0.0 0.0
Obliquebanded Leafroller 0.0 1.0 2.0
Lesser Appleworm 0.0 0.0 1.0
Apple Maggot 0.0 0.0
Brown Marmorated Stink Bug (commercial – mountains) 2.7 1.3 1.7
Brown Marmorated Stink Bug (commercial – upper piedmont) 0.7 3.7 2.0
Brown Marmorated Stink Bug (research – unsprayed) 2.2 0.3 2.0
Spotted Tentiform Leafminer 0.0 0.0 0.0
Dogwood Borer 26.0 31.0 18.0
Peachtree Borer 0.0 1.5 7.5
Lesser Peachtree Borer 47.0 25.0 20.5
San Jose Scale 0.0 0.0 0.0

*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 May 22
May 29
June 5
Codling Moth Apr 30 358 501 654
Oriental Fruit Moth Apr 2 706 883 1071
Tufted Apple Bud Moth May 4 386 564 752
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.