Effects of Inoculum Density and Temperature on Root Rot and Wilt of Chickpea. M. A. Bhatti, Department of Plant Pathology, Washington State University, Pullman 99164. John M. Kraft, Supervisory Research Plant Pathologist, Vegetable and Forage Crops Production, Agricultural Research Service, U.S. Department of Agriculture, Route 2, Box 2953A, Prosser, WA 99350. Plant Dis. 76:50-54. Accepted for publication 23 July 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1992. DOI: 10.1094/PD-76-0050.

A large-seeded kabuli chickpea (cv. Burpee 5043) and a small-seeded desi chickpea (cv. JG-62) were grown at different temperatures (10, 15, 20, 25, and 30 C) with a range of inoculum densities of four root pathogens. Root rot or wilt increased with increased inoculum levels of Fusarium solani f. sp. pisi, F. oxysporum f. sp. ciceris, Pythium ultimum, and Thielaviopsis basicola. F. o. ciceris was equally pathogenic to both cultivars, and wilt severity did not increase with increased inoculum levels of 10⁴ or 10⁵ microconidia and macroconidia per milliliter. However, wilt symptoms were less severe at 10, 15, and 20 C than at 25 and 30 C. Similarly, F. s. pisi caused the most root and hypocotyl necrosis on both cultivars at 30 C. At 10, 15, or 20 C, however, the pathogen caused very little disease on cultivar JG-62. Thielaviopsis and Fusarium root rots were most severe when plants were grown at 30 C and exposed to 5,000 cfu/g of T. basicola and F. s. pisi.