Evaluation of soil solarization for control of root diseases of row crops in Victoria

The effect of soil solarization on the viability of plant pathogens and disease was evaluated in Victoria. The treatment was tested in NW and S Victoria with natural soil inoculated with high inoculum levels of Eusarium oxysporum, Plasmodiophora brassicae, Sclerotium cepivorum, Sclerotinia minor, Sclerotinia sclerotiorum, Verticillium dahliae and the nematodes Meloidogyne javanica and Pratylenchus penetrans. Other experiments were established at sites with a previous history of disease.
Solarization of artificially inoculated soils reduced inoculum levels to at least a depth of 10 cm and effectively controlled diseases caused by P. brassicae on broccoli, and S. minor and S. sclerotiorum on lettuce. The treatment reduced inoculum levels but not disease of carnations and watermelons affected by E. oxysporum , tomatoes affected by M. javanica , celery affected by P. penetrans , and onions affected by S. cepivorum. Results were inconclusive for tomatoes affected by V. dahliae.
Experiments in naturally infested soils established that solarization reduced disease and increased yields of Chinese cabbage affected by P. brassicae , celery affected by P. penetrans , lettuce affected by S. minor and watermelon affected by root rot.
Solarization reduced disease of onions affected by S. cepivorum but did not significantly increase yield. At all sites the treatment reduced the number of viable propagules of the pathogens to at least a depth of 10 cm.