抄録
For estimating the degree of damage of the rice plants affected with sheath blight (Hyp. Sasakii Shirai), following formula has been proposed.
Degree of severity(%)=3n1+2n2+1n3+0n4/3N×100
where, N=n1+n2+n3+n4: n1…number of stems having affected upper leafsheaths up to the top leaf: n2…number of stems having blighted upper leafsheaths except the top leafsheath: n3…number of stems having blighted leafsheaths except uppermost 2 leafsheath: n4…number of stems having the 4 uppermost leafsheaths healthy.
