Physical, Biological, and Chemical Control Integrated for Soilborne Diseases in Potatoes

Abstract

Solar heating of the soil (by polyethylene mulching) or the fumigant methyl bromide, when tested under field conditions, significantly reduced diseases caused by Rhizoctonia solani and Verticillium dahliae. The biocontrol agent Trichoderma harzianum reduced R. solani disease. Combining solar heating or methyl bromide with T. harzianum improved their efficiency and also resulted in the control of Sclerotium rolfsii. The methyl bromide treatment significantly increased the yield by 64% in one experiment. Both T. hariazanum and solar heating reduced the inoculum potential of R. solani and its build-up in the field and under greenhouse conditions. This was more pronounced when the 2 treatments were combined. Vapam, methyl bromide or solar heating killed 76-100% of the S. rolfsii sclerotia buried in the soil during treatment. Combining heat treatment and T. harzianum, both at sublethal doses and under greenhouse conditons, resulted in 90-100% control of S. rolfsii disease in beans. Integrated control of soil-borne disease in potatoes was achieved by an optimal combination of physical, chemical and biological means.