Biological Control of Rhizoctonia solani by Trichoderma harzianum in Carnation. Y. Elad, Research Assistant, Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot 76 100, Israel. Y. Hadar, Research Assistant, Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot 76 100, Israel; Ester Hadar, Agricultural Advisor for the Ministry of Agriculture, Extension Service, Rehovot; and I. Chet and Y. Henis, Professors, Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot. Plant Dis. 65:675-677. Accepted for publication 11 December 1980. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-675.

Wheat bran culture of Trichoderma harzianum was tested for control of Rhizoctonia solani in carnation in fields treated with methyl bromide. A linear correlation was obtained between rate of T. harzianum preparation applied to soil and degree of disease control. Disease incidence was reduced 70% when the T. harzianum preparation was applied at 150 g (dry wt) per square meter. T. harzianum gave best disease control when applied and established in the rooting mixture before transplanting in the field. This method was superior to the broadcast application because it required lower rates of application.

Keyword(s): biocontrol, pentachloronitrobenzene, soilborne pathogens, stem rot.