Evaluation of fungicides for control of stripe rust of winter wheat in southwest Georgia, 2014

摘要

A fungicide trial was conducted at the University of Georgia, College of Agricultural and Environmental Sciences Research Farm in Plains, GA. Prior to seeding, 500 lb/A of 5-10-15 fertilizer was incorporated into the soil. Wheat varieties 'SS8308' (susceptible to stripe rust) and 'USG 3120' (moderately susceptible to stripe rust) were drilled at an 18-20 seed/row foot rate on 15 Nov 13. Seed was planted into clean-tilled soil that had been planted with wheat the previous season. All seed was treatedwith Dividend Extreme (4 fl oz/cwt) and Gaucho 480 (3 fl oz/cwt). Plots were top dressed with 80 lb/A of N on 20 Feb. Treatment plots were 5 ft wide and 10 ft long, separated by 5 ft alleys, and were arranged in a randomized complete block design with four replications. Spreader pots containing Puccinia striiformis-infected plants were placed throughout the blocks on 06 Dec 13 and 19 Dec 13. Test plots were also spray-inoculated with urediniospores of P. striiformis using a backpack sprayer on 04 Feb. Treatment applications at Feeke's 4.5-5 were sprayed on 14 Mar and treatment applications at Feeke's 9-10 were sprayed 8 Apr. All treatments were applied with a CO2-pressurized backpack sprayer and a hand held boom fitted with TJ8001 VC nozzles spaced 18in. apart, which delivered 50 gal/A at 25 psi. Severity of stripe rust (%) was assessed 25 Apr. Plots were harvested using a Hege plot combine on 6 Jun. Grain was cleaned and yields and test weights were determined. Yield was adjusted to 13% moisture.