Comparison of fungicide combinations including mandipropamid for the control of downy mildew in pumpkin, 2008

摘要

This trial was conducted on a Bojac fine sandy loam soil (organic matter <1%) at Virginia Tech’s Eastern Shore Agricultural Research and Extension Center in Painter, VA. Nitrogen was applied at the rate of 100 lb/A and broadcast incorporated on 16 Aug. Cucumbers were seeded on 18 Aug. During the growing season recommended practices for weed and insect control were followed. Plots consisted of single, 25-ft rows spaced 6-ft apart. Treatments were replicated four times and were arranged in a randomized complete block design. Treatments were applied with a CO2-pressurized backpack sprayerthat was calibrated to deliver 40 gal/A at 30 psi. The spray boom consisted of three nozzles spaced 18 in apart and fitted with TeeJet 11003 twin flat fan nozzles. The two outer nozzles were mounted on 15-in drop tubes. Sprays were first applied on 13Sep and reapplied on 22, 29 Sep, 4, 13, and 21 Oct. For powdery mildew control all treatments (including the non treated control) were cover sprayed with Procure 50WS at 6 oz/A alternated with Nova 40W at 5 oz/A. Downy mildew incidence(percentage of leaves infected) and severity (percentage of leaf surface infected) ratings were taken on 23 and 28 Oct. Pumpkins were harvested 28 Oct.