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Spray timing to control Botrytis fruit rot and tarnished plant bug in day-neutral strawberries, 1991I
Entomology Reports
  • M. Gleason, Iowa State University
  • G. Nonnecke, Iowa State University
  • D. Lewis, Iowa State University
  • S. Parker, Iowa State University
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The trial was held at the Iowa State University Horticulture Farm in 1991. Day-neutral strawberries planted in May 1991 on sand loam (fine, loamy, mixed mesic, Typic Halpudoll) soil were arranged in a randomized complete block design with five replications and 3 treatments. Each block was a 100-ft-long double row of plants with 12-in. spacing between plants, and treatment subplots within blocks were 20-ft segments of the double row. Data were taken only from the center 15 ft of each subplot. Timing of fungicide sprays for Botrytis fruit rot in the "model-driven" treatment was based on a leaf wetness-temperature model proposed by M. Ellis (pers. comm., Department of Plant Pathology, OARDC, Wooster, Ohio and Bulger et al, Phytopathology 77:1225-1230). Timing of insecticide sprays for tarnished plant bug in the "modeldriven" treatment was based on published criteria (Kovach et al. 1990. Strawberry Scouting Procedures. Bulletin No . 203, New York State IPM Program. p. 18). In the "weekly" treatment, insecticides and fungicides were applied at 7-day inter-vals. No pesticide sprays were applied in either treatment until blooms appeared (5 Jul). Fungicides used (rates per 100 gal) were Ronilan FL (0.5 pt) or Rovral 50 WP (8 oz), tank-mixed with Captan 50 WP (2 lb). The insecticide used was Sevin 50 WP (2 lb). Pesticides were applied to runoff, using a Solo backpack sprayer (Model No. 425) with a flat-fan nozzle at approximately 30 psi pressure. Leaf wetness and temperature were measured in an apple orchard 0.3 mi from the strawberry plot, using a CR-10 micrologger and appropriate sensors (Campbell Scientific, Logan, UT). Tar-nished plant bug (TPB) populations were monitored weekly by tapping 10 fruit clusters per subplot into a white plastic dish and counting the number of TPB nymphs. The action threshold for insecticide spraying in the "modeldriven" treatment was a mean count of 0.5 nymphs/cluster. Ripe fruit were picked by hand, counted, and weighed one to three times/wk. At each picking, damaged berries were classed by the probable source of damage, and these classes were counted and weighed.

Copyright Owner
The American Phytopathological Society
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Citation Information
M. Gleason, G. Nonnecke, D. Lewis and S. Parker. "Spray timing to control Botrytis fruit rot and tarnished plant bug in day-neutral strawberries, 1991I" (1992)
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