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POSTERS: Cultural control

Effect of biofumigation with solarization in suppressing Phytophthora root and crown rot on field-grown boxwood
Mary Holden - Tennessee State University. Bharat Pokharel- Tennessee State University, Terri Simmons- Tennessee State University, Fulya Baysal-Gurel- Tennessee State University

Phytophthora root and crown rot, caused by Phytophthora nicotianae, is one of the major limitations to boxwood production. In this study, we evaluated the efficacy of biofumigants with solarization for controlling Phytophthora root and crown rot of boxwood. Ground beds were inoculated with P. nicotianae grown on rice grains and inoculated/non-biofumigated non-solarized, non-inoculated/non-biofumigated non-solarized beds were used as controls. Treatments were yellow mustard ‘White gold’, turnip ‘Purple top forage’, arugula ‘Astro’, mighty mustard® ‘Pacific Gold’, rape ‘Dwarf essex’, mustard green ‘Amara’, brown mustard ‘Kodiak’, biofumigant Dominus (170 and 340 lb/A), mustard meal (968 lb/A) and only solarization. All biofumigant incorporated as well as solarization alone beds were covered with polyethylene film for 30 days. After the 30-day period, boxwood plants were transplanted into the ground beds. At the end of the experiment, plant growth data were recorded, and roots were assessed for disease severity using a scale of 0-100% roots affected. All treatments except both rates of Dominus and turnip ‘Purple top forage’ significantly reduced disease severity compared to the inoculated/non-biofumigated non-solarized control. Mustard green ‘Amara’ incorporation with solarization significantly increased the total fresh weight compared to other treatments and controls. Phytotoxicity were not observed in any of the boxwood plants.