Efficacy of selected fungicides and fungicide programs for managing powdery mildew on pumpkin, 2016

摘要

The experiment was conducted at The Pennsylvania State University Russell E. Larson Agricultural Research Center in Pennsylvania Furnace, PA. Nineteen raised beds were formed in early Jun with 1.5-mil black-plastic mulch and a single row of drip-irrigation. Raised beds were 48 in. wide and 6 in. high and were laid on 13-ft centers. Each one-row plot was bordered on one side by an untreated guard row and on the other side by an equipment drive row. On 9 Jun, plots were direct seeded with two seeds perhole and spaced 36 in. apart, one row per bed. The single-bed plots were 20 ft long and separated within the row by a 22-ft unplanted section. Plots were thinned to one plant per hole so that each plot consisted of six plants. Fungicide treatments werereplicated four times and arranged in a randomized complete block design. Fungicide applications were made on 26 Jul and 2, 9, 16, and 23 Aug using a tractor mounted, R&D CO2 powered side boom sprayer calibrated to deliver 42 gal/A at 32 psi at the tankthrough 6 TX-18 hollow-cone nozzles on 20-in. centers. Natural inoculum was relied upon for initial inoculum. Powdery mildew severity was evaluated on 28 Jul and 3, 8, 11, 18, and 25 Aug based on the percentage of upper and lower leaf surface showing symptoms on 6 leaves/plot. Rainfall totals were 1.60, 1.61 and 6.36 in. for 9 to 30 Jun, Jul, and 1 to 25 Aug, respectively.