Abstract
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.
