ピレスロイドおよびメチルパラチオンの包接化合物の二, 三の棉畠昆虫への効果 Effect of the Inclusion Compounds of Pyrethroids and Methyl Parathion on Certain Cotton Insects

メチルパラチオンはβ-シクロデキストリンに包接され1 : 2または1 : 1の包接モル比を与えた.メチルパラチオンと4種のピレスロイドbioallethrin, tetramethrin, resmethrin, pyrethrinsの包接化合物の棉畠昆虫に対する室内殺虫効果を検討したところ, 包接メチルパラチオン(1 : 2比)はAnthonomus grandis(ワタミゾウムシ)に対し遊離メチルパラチオンと同等の効果を示す一方, その残効性はきわめて長くなり, 温室内で棉植物の葉上10日後でもほとんど分解しなかった.しかし寄生蜂の一種Campoletis sonorensisへの毒性は包接化によってあまり減らなかった.ピレスロイドはいずれもC. sonorensisに低毒性であり, 包接化によりさらに安全性が高められるがA. grandisの殺虫には包接物は遊離ピレスロイドより高濃度が必要のようである.Heliothis virescensに対し包接メチルパラチオンは有効であったが, 包接ピレスロイドは十分摂食されていても無効であった.

Methyl parathion is included in beta-cyclodextrin in 1 : 2 or 1 : 1 molar ratio. These and the inclusion compounds of four pyrethroids including bioallethrin, tetramethrin, resmethrin, and pyrethrins were examined for their insecticidal activity to certain cotton insects under laboratory conditions. Included methyl parathion (1 : 2 ratio) was as toxic as free one to Anthonomus grandis, while the persistency was remarkably improved, almost all remaining after 10 days on cotton leaves under green house conditions. Inclusion did not much reduce the toxicity of methyl parathion to a parasitoid, Campoletis sonorensis, but the possible reduction in use by inclusion may reduce its side effect to natural enemy of cotton pest insects. Pyrethroids were far less toxic to the parasitoid than methyl parathion and the inclusion further improve the safety characteristic. However, higher doses seemed required for included as compared to free pyrethroids to kill Anthonomus grandis. To Heliothis virescens the included methyl parathion was toxic, but pyrethroids were toxic only by contact, and the insect which fed the included pyrethroids seemed not to be affected.