Effect of host resistance and fungicide application on rice leaf blast management.
1989
Kim C.H. | Kim C.K. | Lee E.J.
Fungicide application and host resistance in combinations were evaluated to manage rice leaf blast with intention to increase benefit by reducing number of fungicide applications. Rice cultivars Nagdong; susceptible to blast, Cheonma; moderately resistant, Unbong; resistant, were grown in field plots to receive 0 to 2 times of fungicide applications as treatments for controlling leaf blast. Development of panicle blast kept minimum by fungicide applications. Number of applications significantly affected leaf blast development on Nagdong. Maximum disease in this cultivar reached at about same time with severity of 52 %, 41 % and 13 % in the plots of unsprayed check, one and two fungicide applications with Beam 75 % WP, respectively. Area under disease progress curve was also significantly different among treatments on Nagdong. Despite, yields did not differ between treatments. Virtually no leaf blast was developed on other two cultivars regardless of treatment. Analysis of variance on yield data with three cultivars indicates presence of significant effects for cultivar but not for treatment and treatment x cultivar interaction. This result indicates that leaf blast control by fungicide applications may not be justified economically at least on the susceptible cultivar Nagdong.
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