Evaluation of Abound, Convoy, and Folicur for stem rot control on stevia in North Carolina, 2014

摘要

Stevia is a perennial being investigated as a new crop in NC. The commercial stevia line G7 was planted at Caswell Research Station in Kinston, NC on 31 May at a density of two plants per row ft in an unirrigated field with a history of stem rot and previously planted to a corn - soybean rotation. Plots consisted of four 25 ft rows on 30 in. centers, arranged in a randomized complete block with five replications. Recommendations for fertility and weed control were based on grower guidelines from Sweet Green Fields, the sole contractor for stevia in NC. No fungicides are labeled for use on stevia in the US, and this trial was conducted to gain initial efficacy data on products that are used to control stem rot on other field crops. Foliar fungicideswere applied at regular intervals as a full canopy spray using a CO2 pressurized (40 psi) backpack sprayer equipped with a two row hand-held boom with TP8006 flat fan nozzles calibrated to deliver 30 gal/A at a 3.0 mph walking pace. Stand counts were taken on 17, 26 Jun, 10, 29 Jul, 6 and 20 Aug to monitor disease incidence and progression. Final mean percent stand loss was recorded on 20 Aug, two weeks following the final fungicide application, by comparing end of season stand counts to the original stand count of each plot at planting. Yields were calculated by harvesting 8 ft sections from the center two rows of each plot on 26 Sept.