Potato growth and tuber production as affected by inoculation of cut and whole seed withRhizoctonia solani (AG 3) and the use of seed treatment fungicides

Abstract

A potato seed tuber inoculation technique forRhizoctonia solant resulted in consistent field study results and demonstrated a reduction of about 15% in early plant vigor ratings 30 days after planting. Plant stands were generally unaffected by the introduced pathogen presence around the potato seed. After 45–60 days’ growth, inoculated seed had significant increases in the number of weak plants compared to the uninoculated seed. The impact ofR. solani on daughter tuber production included significant total yield losses in two of three years and seed inoculation increased the severity of black scurf on daughter tubers with significant differences occurring two of four years. Use of whole seed resulted in similar early plant vigor losses as was found for cut seed but inoculated, whole seed treatments had fewer weak plants and less yield loss than inoculated, cut seed treatments. Pre-planting seed treatment fungicide applications resulted in a few significant differences in plant growth and yield depending on the fungicide used. Black scurf incidences on daughter tubers were generally reduced but significant differences were more frequent for whole than cut seed treatments. However, none of the commercially available seed treatment fungicides provided consistent disease control. Aspects of disease incidence, development and control for potato production conditions in the northeastern region are also discussed.