Pathogenicity of Corynespora Cassiicola on Soybean

Abstract

Corynespora cassiicola was pathogenic on the roots and hypocotyls of soybean seedlings grown in infested soil at Ottawa. Extensive superficial necrotic lesions developed on seedlings from inoculated seeds planted in the field in mid-May, but few symptoms appeared on seedlings planted in late May and in June. Infected plants were initially stunted but recovered with little effect on size or yield. In controlled temperature studies, severe root and hypocotyl rot were produced on inoculated seedlings at 15–20 °C. Symptoms were less severe at temperatures alternating from 15 or 20 °C to 25–35 °C and were negligible on seedlings kept constantly at 25–35 °C. Optimum growth of the fungus on agar media occurred at 20 °C. At 5 °C and 35 °C conidia germinated, but no appreciable mycelial growth occurred; at 30 °C growth was greatly restricted. Typical symptoms of target spot were produced on the inoculated foliage of soybeans in the greenhouse and in the field, but secondary infection was not observed in the field. Foliage infection occurred on cowpea (Vigna sinensis), sesame (Sesamum indicum), and Hartsville cotton (Gossypium hirsutum) in the greenhouse. C. cassiicola was isolated from overwintered soybean root debris, from the roots of mature field bean (Phaseolus vulgaris), and from the roots of soybean seedlings grown in soil not previously cropped with soybeans.

Mycoflora of Soybeans Used for Meju Fermentation

“…Fusarium oxysporum and F. solani were reported as pathogens causing Fusarium wilt, Fusarium blight and root rot of soybeans in Korea [17]. Phomopsis longicolla and Corynespora cassiicola were reported as pathogenic fungi to soybeans in other countries [18, 19]. Additionally, B. dothidea , F. fujikuroi , Khuskia oryzae , and P. oxalicum , were reported as pathogenic fungi in other plants [17].…”

Morphological and molecular analysis of genetic variability within isolates of Corynespora cassiicola from different hosts

“…usually causes target spot on leaves but also on stems, roots and flowers of more than 280 host plants from over 70 tropical and subtropical countries (Farr et al 2007). The organism has been reported on a great number of economically important crops including tobacco (Fajola and Alasoadura 1973), cowpea (Olive et al 1945), eggplant (Onesirosan et al 1974), sesame (Stone and Jones 1960), tomato (Mohanty and Mohanty 1955), soybean (Seaman and Shoermaker 1964), cucumber (Blazquez 1967), cotton (Jones 1961) and Hevea rubber (Deighton 1936). The Corynespora Leaf Fall (CLF) disease caused by the fungus C. cassiicola was first identified on Hevea rubber (Hevea brasiliensis) in Sierra Leone in 1936 (Deighton 1936).…”

Root-Surface Mycoflora of Soybean in Relation to Soil Temperature and Moisture in a Field Environment

“…The absence of corynespora rot may be attributable to the late seeding (June 14). Seaman et al (1965) found that early plantings of infected seedlings (mid-May) favored corynespora rot, whereas later plantings in June resulted in a negligible amount of root rot. Moreover, the presence of this fungus may account for the poor germination of the flrst seeding (Mack and Ivarson 1972).…”