It will be said that, until systemic imsecticides have been imported into Japan, nearly all studies on the chemical control of the rice-stem borer which causes the injury by boring in the stem were done with the aim to protect the rice plants from attacking by this insect.
In the present paper, the authors have some small scale studies in the paddy field to make clear the effect of benzene he achloride for control of the young larvae of the rice stem borer which have been fed into the leaf sheaths or the whorls but not yet into the inner parts of the rice stems.
Results obtained are as follows:
1. BHC-dust is excellently effective for the young larvae of the rice-stem borer even if it is applied for the above mentioned condition.
2. For this purpose, BHC-dust must be contained 3 per cent of gamma isomer.
3. In the Northeast district in Japan the period of the effective using of BHC-dust are limited until about 30 days after transplanting of rice seedlings.
4. In the said district, only of an application BHC-dust is enough to control the injury caused by rice-stem borer, but in the other districts where the hatching time is much longer than in that the Northeast district, twice or 3 times dustings will be more effective.
5. If the BHC-dusting is applied after the larvae had entered into the inner parts of the stems and has withered the top leaf of injured stem, the effect of the dusting becomes rather imperfect.
6. In the second generation of the rice-stem borer the effect of BHC-dusting is not so evident as in the first generation.

View full abstract

[in Japanese]

View full abstract

In order to contorol the soy bean root miner, Ophiomyia sp., DDT dust (5%) and BHC dust (0.5% in γ) were used four times during the period of appearance of the flies. By these treatments, the population of flies and the ovipositing activity are little influenced, but the larvae are strongly affected and dead after eating small amount of the root, and thus the pupae remarkably decreases in number. BHC is more effective than DDT.

View full abstract