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 Wednesday afternoon from April through September. Learn more about southeastern apple pests at the Apple Pest Management page.


Weekly summary

July 25, 2016

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Codling Moth: Codling moth degree-day accumulations since biofix ranged from about 1850 in Henderson County to about 2250 in the Lincolnton/Hickory area as of Monday (July 25).  Hence, the primary flight of the second generation is nearly complete in the piedmont production areas, and will be a concern for only another week or two in higher elevation locations.  However, second-generation flight can extend for longer periods in some orchards, so the need for insecticides should be based on pheromone trap captures in individual orchards.

Brown Marmorated Stink Bug (BMSB): Late last week we observed an increase in BMSB adult captures in pheromone traps in Polk, Cleveland and Lincoln Counties, which coincides with the expected time of first generation adult emergence in these areas. First-generation adult emergence and activity will continue into September.  Based on monitoring in 2015, it is these adults that are the primary cause of damage to apples in NC.  Hence, in orchards with a history of BMSB damage at lower elevations, insecticide applications targeting this insect should begin at this time.  Insecticides with greatest activity include the neonicotinoids dinotefuran (Venom or Scorpion) or Belay, which has a Section 18 emergency exemption registration, and several pyrethroids, including fenpropathrin (Danitol), lamda-cyhalothrin (Warrior), and gamma-cyhalothrin (Proaxis).  Bifenthrin (Brigade, Bifenture) is also highly effective, and a Section 18 emergency exemption has just been approved for its use in NC.  (See the article on recent Section 18 exemptions.) There are also several pre-mixes that are effective, including Indigo (lambda-cyhalothrin + thiamethoxam), and Leverage (beta-cyfluthrin + imidacloprid).

We have not yet observed first generation BMSB  adult emergence in higher-elevation orchards (i.e., Henderson County), and pheromone trap captures remain very low at all of our trapping sites.  First-generation adults typically begin to emerge in highest numbers in mid-August in Henderson County.

Apple Maggot: Finally, we are approaching the time when apple maggot emergence typically begins in NC – late July to early August. Numbers remain low at our trapping sites, but this insect has a highly aggregated distribution on an area-wide basis, so population densities can vary considerably among orchards that may be only a half-mile apart.  Hence, for those growers not trapping for this insect, it would be wise to include imidacloprid as a precaution in sprays over the next couple of weeks.

Archived Pest Reports for 2016


2016 Average Weekly Trap Captures*

HENDERSON COUNTY
Insects per trap
Jul 11
Jul 16
Jul 25
Codling Moth
14.5
8.0
4.5
Oriental Fruit Moth
2.7
3.3
4.7
Tufted Apple Bud Moth
0.0
0.0
2.0
Redbanded Leafroller
0.0
0.0
0.0
Obliquebanded Leafroller
0.0
1.0
0.0
Lesser Appleworm
0.0
0.0
3.0
Apple Maggot
0.5
1.0
1.0
Brown Marmorated Stink Bug
0.8
0.0
0.0
Spotted Tentiform Leafminer
56.0
19.0
10.0
Dogwood Borer
52.0
31.0
19.0
Peachtree Borer
21.5
35.5
24.5
Lesser Peachtree Borer
16.5
10.5
10.5
San Jose Scale
6.0
3.0
21.5
*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.

2016 Accumulated Degree Days


Henderson County
 Biofix
Jul 11
Jul 18
Jul 25
Codling Moth
April 15
1492
1659
1842
Oriental Fruit Moth
March 21
2085
2287
2505
Tufted Apple Bud Moth
April 20
1815
2017
2236
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.

2016 Pest Trends (click to enlarge)

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