Pre-harvest burning for control of tuber infection byAlternaria solani

Pre-harvest propane burning of vines and soil surface significantly reduced populations ofAlternaria solani spores on the soil surface in field studies. Infection of potato tubers harvested from burned fields was reduced in most cases. Laboratory studies indicated a minimum temperature of 200°C for 1–2 seconds was required to significantly (P = 0.05) reduce germination ofA. solani spores. This temperature was achieved at the soil surface in the field when plots were burned at tractor speeds of 2, 3, 4 and 5 mph. In practice burning at only 2, 3 and 4 mph significantly reduced spore populations and tuber infection in the field. Recontamination of plots after burning occurred relatively rapidly. The data show that propane burning at tractor speeds of 2–4 mph can effectively reduceA. solani infection of potato tubers by lowering fungus populations on the soil surface.