Potential use of Exserohilum monoceras as a biological control agent for Echinochloa spp. (barnyard grass) in Vietnam

Nguyen Van TuatA, Tran Hu HanhA, Shane D. HetheringtonB, Duong Van ChinC and Bruce A. AuldB

A National Institute of Plant Protection, Chem, Tu Liem, Hanoi, Vietnam.

B NSW Agriculture, Orange Agricultural Institute, Forest Road, Orange, New South Wales 2800, Australia.

C Cuu Long Rice Research Institute, Omon, Cantho, Vietnam.


Summary

Exserohilum monoceras causes a leaf blight on Echinochloa crus-galli a grass weed of rice cultivation. Indigenous isolates of this fungus were collected from north, central and south Vietnam. Two isolates were chosen to examine the severity of this disease on E. crus-galli and to determine if the fungus could infect rice. Following inoculation, rice and E. crus-galli were exposed to moist periods of 8, 12 and 24 hours and their height and mortality measured 5, 10 and 15 days after inoculation (DAI). The above ground dry weight of all plants was measured 15 DAI. Rice height, above ground weight and mortality did not differ from uninoculated controls after any treatment. All E. crus-galli plants were dead 15 DAI. All E. crus-galli plants were dead 10 DAI when they had been subject to post-inoculation high humidity (80-90%) periods of 12 or 24 hours. E. crus-galli height was significantly reduced by inoculation followed by dew periods of 8, 12 and 24 hours. The possibility of using E. monoceras as a biological control agent for E. crus-galli is discussed.

 

Plant Protection Quarterly (1999) 14 (4) 136-138.