Evaluation of biorational products for powdery mildew control on annual strawberry, 2010-11.

摘要

On 13 Oct 10, bare root strawberry transplants were set into fumigated, plastic-mulched beds in an area of the field covered by a high plastic tunnel. Beds were 28-in. wide on 4-ft centers and contained two staggered rows of plants. Treatments were arranged in a randomized complete block design with four blocks in adjacent beds. Plots were 9.4 ft long and contained 14 plants. Transplants were irrigated by overhead sprinkler for 10 days to facilitate establishment, then irrigated and fertilized by drip tape. Treatments were applied every 7 to 14 d from 29 Dec to 2 Mar with a C02 backpack sprayer delivering 100 gal/A at 50 psi through a two-nozzle wand fitted with TeeJet disc-core hollow-cone nozzles. Biorational products were tested in weekly calendar programs, substituting Procure (triflumizole) once on Jan 5 when disease pressure was high (biorational treatments), and in weekly alternations with Procure (alternation treatments). Marketable yields and disease parameters were determined between Janand Mar. Fruit were harvested 16 times at 3- to 4-day intervals from 4 Jan to 11 Mar. Marketable fruit were counted and weighed. Fruit with visible powdery mildew on more than 25% of the achenes and other unmarketable fruit were also enumerated. Fruit disease incidence was expressed as a percentage of all marketable and urrmarketable fruit.