1996 Geauga County IPM Program
Principal Investigator:
Mardy Townsend, Extension Agent, Geauga Co
Abstract:
Three apple orchards and five vegetable farms participated in the 1996 Geauga County IPM
Scouting program. Two of the orchards had been in business for four generations, and the other
for more than 30 years. The experience of the vegetable growers ranged from three to twelve
years. This difference in experience is generally representative of Geauga's horticulture industry.
The apple growers were interested in fine tuning their pest control strategies and identifying
beneficial insect populations. The vegetable growers were more interested in identifying the
specific pest problems of the year.
Two part-time scouts for the summer were hired. The orchard scout was employed from early
June to mid-September. The vegetable scout was employed from late June to early September.
The Geauga County Extension Agent trained both scouts.
Vegetable Scouting Program
The cool wet weather and soils of spring and early summer caused many early symptoms of
physiological stress in all vegetables except the cole crops, making it often a challenge to
distinguish between weather related stress and insect or disease damage. The unusually cool
temperatures persisted through the entire season, allowing very high populations of flea beetles
and striped cucumber beetle the entire growing season. High aphid populations caused leaf
deformation early in peppers. Potato leaf hopper (PLH) populations in vegetables and field crops
were the highest in many years. PLH caused severe hopper burn on green beans and potatoes.
Colorado potato beetles on potatoes were monitored, and economic thresholds developed using
the model in the 1996 Ohio Vegetable Production Guide (OSUE).
Diseases were also monitored. High aphid populations caused a higher incidence than normal of
mosaic viruses in vine crops. Also in vine crops, levels of bacterial wilt transmitted by cucumber
beetles were higher than usual. The unusually low temperatures, and unusually dry August,
delayed development of fungal diseases except for early blight in tomatoes, which was very
severe this year. Septoria leaf spot was also severe in tomatoes. The vine crop fungal diseases
did not appear until the end of August.
The vegetable scout walked the entire fields of each operation on each visit. The scout
monitored traps for corn earworm (CEW) in all pepper fields and variegated cutworm in one
tomato field. Unlike 1995, CEW in peppers was not a problem this year. A copy of the written
report, along with a verbal explanation, was given by the scout at the end of each visit.
Apple Scouting Program
The orchard scout monitored traps for codling moth (CM), San Jose Scale, and apple maggot.
Trees were visually scouted for rosy apple aphid, white apple leafhopper, European red mite
(ERM), and spotted tentiform leafminer. Predator insect populations were also monitored. Apple
growers found that methodical scouting confirmed their suspicions of their worst insect problems.
ERM and CM were the two biggest problems in 1996, although an outbreak of rosy apple aphid
occurred in one orchard. One site had ERM pressure all summer, beginning the first week of
June. No beneficials were ever seen there. Across the three orchards, ERM peaked the last
week in July. Lacewing adult and larvae were first seen the week of July 22-26, and peaked
during the second and third weeks of August. Growing degree days were tracked and used to
determine the BioFix for CM. CM populations had two peaks; the first was the week of June 17-21, and second was the week of August 19-23. CM was caught all summer, beginning June 1.
The trap counts from the orchards were totaled on to a form, along with observations, and a
copy left with the grower at the end of each visit. The apple growers liked the systematic scouting
of their orchards. All were able to lengthen the time between some sprays. However, the frequent
rains made spraying according to thresholds very difficult.
Extension Program Implementation:
The scouts brought reports into the office by Thursday morning each week. Pertinent information
from the Ohio ICM Newsletter and trap counts were included in the weekly "Northeast Ohio
Integrated Pest Management Newsletter". Results were also discussed at evening Growers'
Meetings.
For further information contact the Ohio IPM Office.
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