A method for rearing the rice water weevil, Llssorhoptrus oryzophilus (Coleoptera: Curculionidae), in the laboratory

The purpose of the experiments presented in this paper was to investigate methods for rearing larvae and pupae of the rice water weevil, Lissorhoptrus oryzophilus Kuschel, on rice plants in a laboratory in the absence of mud. Rearing containers were developed in which larvae were reared in a layer of rice roots in water. When mating pairs of adult weevils were used to infest plants, these methods were sufficient to rear weevils from eclosion of eggs to the final instar. When neonates were used to infest rice seedlings in the rearing containers, over 40% of the infesting larvae in two repetitions developed to the 3rd or 4th instar, this rate of survival was not significantly different than survival rates of larvae reared in mud. When 3 rd instars were individually reared in water in test tubes with rice plants, 55.0% of the insects were alive and developing normally on the 15 th day after infestation. Other experiments demonstrated that late-instar larvae and pupae of the rice water weevil may be reared in vermiculite rather than in mud. The experimental results suggest that the methods introduced in this paper for rearing the rice water weevil in water and vermiculite are appropriate for the production of test insects for a variety of experiments in the laboratory