B.L.Ho

Abstract

Scoring at 14 days aftcr inoculation was found to be more meaningful than scoring at 28 days after inoculation and at milk ripe stage.Based on thcse three scoring periods, infected plants were shown to be able to recover from severe infection of bacterial leaf streak at hcading stage. Younger stages of plant growth namely between nursery stage and young ear formation stage have been shown to be significantly more susceptible to the disease than older growth stages (reproductive stages) which showed very poor infection.This coupled with the fact that severely infected plants were able to recover front the attack at heading stage could be attributed to the plants being able to develop resistance to the disease as they became older. Host nutrition has been shown to affect the severity of bacterial leaf streak infection. Application of 100 lbs. N/ac. or more in the form of Urea could induce a significantly higher degree of disease infection than lower levels of nitrogen application. Despite severe disease infection  during the vegetative growth periods with high levels of nitrogen application, the disease was not able to cause significant reduction in rice yields.

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