Evaluation of fungicides for control of Rhizopus soft rot in sweetpotato, 2016

摘要

This experiment was conducted at the Central Crops Research Station in Clayton, NC. Sweetpotato roots used in the study were obtained from a commercial packing facility at the time of each inoculation and were rinsed with water prior to use. Roots were previously cured and were selected based upon similar size, shape, and disease-free appearance. Sweetpotatoes were wounded using a calibrated, rubber-band-propelled wooden dowel. After wounding, roots were inoculated with a spore suspension applied with a 1-inch foam brush. The approximate concentration of the spore suspension was 1.0 x 106 spores/mL. Following inoculation, roots were allowed to air dry. Roots were arranged, wounded side up, and fungicides were applied at specific rates using a CO2-pressurized backpack sprayer. For the dip application, wounded roots were placed into a perforated metal basket and submerged into the fungicide mixture for 1 minute. After fungicide applications, roots were allowed to air dry, and then placed into clear,plastic containers (40 by 50 by 17.9 cm) and stored at 27°C and 99% relative humidity for 21 days. Four replications per treatment were included with 20 roots per replication. Roots were rated for disease incidence and severity 10 and 21 days after inoculation. Data were analyzed in the software ARM (Gylling Data Management, Brookings, SD) using analysis of variance (AOV) and the Waller-Duncan test to separate means.