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Pesticide Sprays to Control Botrytis Rot, Anthracnose, and Tarnished Plant Bug In Day-Neutral Strawberries, 1992
Entomology Reports
  • M. L. Gleason, Iowa State University
  • G. R. Nonnecke, Iowa State University
  • D. R. Lewis, Iowa State University
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The trial was held at the Iowa State University Horticulture Farm. Day-neutral strawberries planted into plastic mulch in May 1992 on sandy loam soil (fine, loamy, mixed mesic, Typic Hapludoll) were arranged in a randomized complete block design with five treatments and four replications. Each block consisted of five 20-ft-long double rows of plants with 12-in spacing between plants in the double rows, and each 20-ft segment was a treatment subplot. In three treatments ("post-infection"), timing of fungicide sprays was based on a leaf wetness-temperature model proposed by M. Ellis (pers. comm., Department of Plant Pathology, OARDC, Wooster, OH, and Bulger et al, Phytopathology 77:1225-1230) for control of Botrytis fruit rot. In the same treatments, timing of insecticide sprays for tarnished plant bug (IPB) were based on thresholds of TPB counts; a spray was applied when the mean number of TPB's (sum of nymphs and adults) per fruit cluster equaled or exceeded the threshold number. TPB numbers were assessed 2x/week by beating 10 fruit clusters per plot (one cluster per sampled plant) twice over a white plastic dish and counting TPB nymphs and adults in the dish. A fourth treatment ("weekly") was a weekly spray of fungicides and insecticides, and a fifth treatment ("unsprayed") received no pesticide sprays. Pesticide spraying was started as berries began to ripen (14 Jul). Fungicides used (rates per 100 gal) were Ronilan FL (0.5 pt) plus Benlate 50 WP (4 oz). After 17 Aug, when anthracnose had become severe, Captan 50 WP (2 lb) was substituted for Benlate. 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. Leaf wetness and temperature were measured approximately 0.3 mi from the strawberry plot, using a CR- 10 micrologger and appropriate sensors (Campbell Scientific, Logan, Ul). Ripe fruit were picked by hand, counted, and weighed 1 to 3x/ 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. L. Gleason, G. R. Nonnecke and D. R. Lewis. "Pesticide Sprays to Control Botrytis Rot, Anthracnose, and Tarnished Plant Bug In Day-Neutral Strawberries, 1992" (1993)
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