RALEIGH — 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.
Codling Moth: Codling moth DD accumulations range from about 1750 in Henderson County to 2125 in Cleveland County, which corresponds to about 40% and 75% completion of second generation egg hatch, respectively. Although second generation populations are generally low in orchards where first generation populations were well controlled, the need for multiple insecticide applications should be based on pheromone trap captures, using a threshold of 5 to 7 moths per trap. In orchards using mating disruption, the need for supplemental insecticides for codling moth should be based on a threshold of an average of 3 cumulative moths over a two-week period.
Oriental Fruit Moth: OFM populations are beginning to increase in several orchards, which is not unusual for this time of the year. In orchards not using mating disruption, they often begin to increase in mid-to-late July, with relatively high populations continuing through September. However, pyrethroid insecticides have provided good control of OFM, so in orchards using pyrethroids for brown marmorated stink bug in August and September, OFM may become less of an issue. One or two applications of sprayable OFM pheromone in late July and late August has worked well for control of late-season OFM.
Brown Marmorated Stink Bug: As indicated in last week’s update, first generation adults are present in lower elevation foothill and piedmont orchards (Cleveland, Lincoln and Burke Counties), so insecticide applications for BMSB should be underway in these areas. Also, first generation emergence is predicted to begin this weekend in the Wilkes County area, so the threat of damage will increase substantially beginning next week. In Henderson County, first emergence of adults is predicted to begin in about 10 days, at which time applications should begin in this area.
Early indications in lower elevation locations are that first generation adult populations appear to be quite high this year. However, the first real heatwave of the year has begun this week, and this may help suppress populations. In previous years we have observed BMSB populations decline in August where temperatures reached the mid 90s or above. Hopefully this response will be a trend and not an anomaly. We’ll continue to monitor BMSB in all locations through September.
BMSB Degree-Day Accumulations and Predications as of July 19 (Biofix = April 10) | |||
Location | DD as of July 19 | Estimated date of first damage to appear (710 DD) | Estimated date of need for first insecticide (635 DD) |
Henderson County | 535 | —a | July 29 |
Wilkes County | 588 | July 31 | July 23 |
Cleveland County | 707 | July 19 | July 12 |
aNot predicted to occur within the next 14 days based on weather forecasts.
Archived Pest Reports for 2017
2017 Average Weekly Trap Captures*
HENDERSON COUNTY | |||
Insects per trap | |||
Jul 5 | Jul 10 | Jul 18 | |
Codling Moth | 12.5 | 15.0 | 14.5 |
Oriental Fruit Moth | 17.5 | 20.0 | 18.5 |
Tufted Apple Bud Moth | 0.0 | 0.0 | 0.0 |
Redbanded Leafroller | 0.0 | 0.0 | 0.0 |
Obliquebanded Leafroller | 0.0 | 0.0 | 0.0 |
Lesser Appleworm | 0.0 | 1.0 | 1.0 |
Apple Maggot | 0.0 | 0.0 | 0.0 |
Brown Marmorated Stink Bug (commercial – Henderson Co.) | 4.3 | 8.3 | 3.8 |
Brown Marmorated Stink Bug (commercial – upper piedmont) | 3.5 | 3.4 | 10.2 |
Brown Marmorated Stink Bug (research – unsprayed) | 23.5 | 9.8 | 18.7 |
Spotted Tentiform Leafminer | 48.0 | 20.0 | 18.0 |
Dogwood Borer | 15.0 | 12.0 | 32.0 |
Peachtree Borer | 15.0 | 33.0 | 56.5 |
Lesser Peachtree Borer | 4.0 | 2.5 | 3.0 |
San Jose Scale | 39.0 | 32.5 | 35.0 |
*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.
2017 Accumulated Degree Days
Henderson County | ||||
Biofix | Jul 5 | Jul 11 | Jul 18 | |
Codling Moth | Apr 10 | 1376 | 1543 | 1718 |
Oriental Fruit Moth | Mar 27 | 1933 | 2135 | 2345 |
Tufted Apple Bud Moth | Apr 13 | 1733 | 1936 | 2146 |
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:
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ORIENTAL FRUIT MOTH:
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TUFTED APPLE BUD MOTH:
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2017 Pest Trends (click to enlarge)
— Dr. Jim Walgenbach
Extension Entomology Specialist (Fruits / Vegetables)
Entomology and Plant Pathology – NC State University
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