EFFECTS OF INOCULUM DENSITY AND TEMPERATURE ON ROOT-ROT AND WILT OF CHICKPEA

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 10(4) or 10(5) 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.