The effect of the fungus, Balansia cyperi Edg., on growth and reproduction of purple nutsedge, Cyperus rotundus L.

Abstract

SUMMARYTwo growth trials were conducted in the greenhouse to determine the effects of the systemic clavicipitaceous fungus, Balansia cyperi Edg, on growth and tuber production of purple nutsedge (Cyperus rotundus L.). In the field, tubers collected from populations of infected plants were significantly smaller than tubers from populations of uninfected plants. There were no differences in percentage of tubers sprouting, or in time to sprouting, between infected and uninfected tubers collected and planted in the greenhouse in September 19S5. Infected tubers collected and planted in January 1986 showed significantly decreased percentage sprouting, and increased time to sprouting, compared with uninfected tubers. In both trials, after correcting for differences in initial tuber size, vegetative tiller (shoot) number increased and inflorescence number decreased for infected purple nutsedge compared to uninfected purple nutsedge. Plants were harvested after 20 weeks in the second trial. Total dry weight of infected plants was greater than total dry weight of uninfected plants, but ratios of below‐ground: above‐ground dry weight were the same. Infected plants produced significantly more, but smaller, tubers than uninfected plants. Greater vegetative growth and production of more tubers may provide and advantage to infected purple nutsedge in mixtures with uninfected plants and other plant species.