Current Western NC Orchard Pest Populations

We track local insect populations throughout the growing season using a system of traps, temperature-recording devices, and degree-day models. Traps and weather data are checked weekly, with results updated by Tuesday afternoon from April through September. Learn more about southeastern apple pests at the Apple Pest Management page.


Weekly summary

May 18, 2015

DSC_0055

Codling moth degree-day models currently range from about 310 DD in Henderson County to over 500 in the piedmont – Bill Hanlin reports 511 in the Wilkes/Alexander County area.  Based on the weather forecast, about 110 to 150 DD are expected to accumulate during the next week, which will remain an important time for codling moth flight.  If not using pheromone traps to monitor populations, one should assume that a potentially damaging population is present.

In those orchards using mating disruption, insecticides should not be necessary against codling moth at this time unless pheromone trap captures indicate otherwise.  In mating disruption orchards, an insecticide is usually not necessary until 500 to 600 DD after biofix, which coincides with the optimum timing for tufted apple bud moth control (about 1000 DD).  In the piedmont regions this should occur later this week, while Henderson County is still at least 10 to 14 days from the 500 DD codling moth time.

Green aphid (green apple aphid and spirea aphid) is the other common pest at this time.  However, the need for chemical control is usually not necessary in most orchards, because biological control often helps to maintain populations below damaging levels.  Control is most important on young trees.


Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
May 4
May 11
May 18
Codling Moth
3.2
10.8
5.0
Oriental Fruit Moth
9.1
14.7
7.0
Tufted Apple Bud Moth
17.5
22.5
61.0
Redbanded Leafroller
0.0
0.0
0.0
Obliquebanded Leafroller
0.0
0.0
1.5
Lesser Appleworm
0.0
0.0
0.0
Apple Maggot
0.0
0.0
0.0
Brown Marmorated Stink Bug
-
-
0.5
Spotted Tentiform Leafminer
0.0
0.0
12.0
Dogwood Borer
0.0
21.0
41.0
Peachtree Borer
0.0
0.0
0.0
Lesser Peachtree Borer
4.0
28.5
60.5
San Jose Scale
1.5
1.5
1.0
*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.

Accumulated Degree Days


Henderson County
 Biofix
May 4
May 11
May 18
Codling Moth
April 23
76
189
309
Oriental Fruit Moth
Apr 6
375
523
677
Tufted Apple Bud Moth
April 23
115
263
417
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.

Pest Trends (click to enlarge)

Slide1 Slide2 Slide3 Slide4 Slide5 Slide6 Slide7 Slide8 Slide9 Slide10 Slide11 Slide12 Slide13

Was the information on this page helpful? Yes No