The effects of three insecticides used for seedling-box application on the population density of the rice water weevil, Lissorhoptrus oryzophilus.
This experiment was conducted in Ibaraki prefecture, Japan, in 2005, to examine the effects of imidacloprid, benfuracarb and fipronil that were used as pesticide for boxed seedlings on Lissorhoptrus oryzophilus. These 3 chemicals were tested on the seedlings of rice cultivar Koshihikari in late April and the effects were examined and compared. The results showed that benfuracarb and fipronil were found effective enough to control eggs, larva and adults of Lissorhoptrus oryzophilus whilst imidacloprid was found less effective on wintering adults. Also LD50 value of adult Lissorhoptrus oryzophilus when local application of these 3 chemicals were carried out were less than 0.1 μg per insect.