The cumulative tiller damage measured on control
villages (13%) was 1.9 times the damage measured on
treated villages (6.8%). This difference translated into
an average yield increase over the 3 years of 380 kg/ha
of rice per season in the treated villages. The average
yield loss in this study was 4.2 times the percentage of
tillers damaged at the ripening stage. In Central Java
and Malaysia, yield losses in rice damaged by rats
versus protected plots varied between three times
(Buckle, 1988) and four to seven times the damage
estimates at ripening (Wood, 1971; Greaves et al.,
1977; Buckle and Rowe, 1981). Therefore, a four
times multiplier of percent damage of tillers at the
ripening stage would provide a conservative estimate
of percent yield loss.