Study on Radiation Disinfestation of Drosophila Bizonata, Harmful Insect of Tricholoma Matsutake

This experiment was undertaken to obtain the fundamental data for prevention of mushroom, Tricholoma Matsutake from harmful insect by gamma irradiation. Futaobishvojo-bae, Drosophila bizonata which is main harmful insect to the mushroom was irradiated by gamma ray from137Cs. Radiosensitivity on each development stage of this insect was as follow. Egg: About 100% inhibition of hatching was observed with irradiation of 25K rad. It was also observed that the life span of larvae hatching from irradiated egg was shorter than the control, and larvae from irradiated egg with 15 K rad died immediately after hatching. Larvae: Pupation of larvae was perfectly inhibited by irradiation of 18 K rad, and no larvae died. Feeding and movement of the larvae are one of the most considerable factor to keep the quality of the mushroom. The dose required to inactivate the movement and feeding were 40K rad and 70 K rad respectively. Pupa: Emergence of pupae was completely inhibited with the dose of 40 K rad. It was also observed to occur the deformation and sterilization of adult from irradiated pupa. Adult: The life span of the irradiated adult became increasingly longer with the dose less than 80K rad, under which the adult lived two times longer than the control. The more dose than the above brought to shorten the life span and the dose required to kill immediately after irradiation was 150 K rad. The minimal dose appeared to be 70K rad to prevent the mushroom from Futaobishyojo-bae, D. bizonata.