Efficacy of fungicide treatments for suppression of downy mildew on cabbage, 2007.

摘要

Moreton cabbage transplants started in a soil less mix were set by hand on 1.25 mil black polyethylene with drip irrigation on 14 Jun into Lima silt loam on Gates farm, Geneva, NY. Prior to planting, 500 lbs 10-10-10 (50lb/N/A) fertilizer was incorporated into the field. The seedlings were treated with a starter fertilizer 15/30/15 at the labeled rate on 13 Jun. Six treatments and the untreated control were arranged in a randomized compete block with four replications. Each plot consisted of 10 plants spaced 12 in. apart. Rows were 9 ft apart with ryegrass planted between for weed control. Rainfall (in.) was 0.59, 2.62, 1.50, and 2.26 for Jun, Jul, Aug, and Sep respectively. The field was irrigated 1 in. every 2 weeks. Fungicides were applied with aCO2 pressurized backpack sprayer at 40psi delivering 40 gal/A through two flat fan nozzles. Sprays were applied on a 7 day schedule beginning 18 Jul. A natural infection of downy mildew was observed beginning on 20 Aug. The numbers of plants with downymildew lesions were counted for incidence and severity was rated by estimating the percentage of leaf tissue infected. All data were analyzed using one-way ANOVA at P =0.05 and significant differences were separated using Fisher’s LSD at P =0.05.