2009 Volume 2009 Issue 60 Pages 167-169
The effect of the rice ripening stage on the occurrence of white-spotted rice grains caused by Trigonotylus caelestialium and Stenotus rubrovittatus was examined. The number of white-spotted rice grains per panicle did not differ significantly between the 2 bug species and also between 2 rice varieties, but a significant difference was observed among the 3 ripening stages. The numbers of affected grains at 31 and 40 days after heading were more than the number noted at 22 days. More grains were affected by T. caelestialium at 31 days than at 40 days while more grains were affected by S. rubrovittatus at 40days than at 31 days. These results suggest that the occurrence of white-spotted rice grains is affected by the ripening stage and that this stage may differ between the 2 bug species.
