Wirkungen einesBacillus thuringiensis-Präparats und eines Juvenilhormon-Analogons über den Erdboden aufSpodoptera littoralis (Boisd.) (Lep.,Noctuidae)

Summary Sensitivy of Spodoptera littoralis (Boisd.) to soils treated with preparations of Bacillus thuringiensis and of a juvenil hormone analogue Various instar larvae ofSpodoptera littoralis were exposed to soil treated, with aBacillus thuringiensis-containing preparation (Bactospeine) and a juvenile hormone analogue (Ro 20–36 000).After treatment with Bactospeine, only high concentrations could affect emergence. Suppressed egg laying and sterility were the most marked effects. Also, the produced eggs were smaller in size.The juvenile hormone analogue showed high activity, particularly against freshly moulted 6th. instar larvae. Greater effects were elicited after ecposing the larvae to treated soil than to treated leaves for 48 hours. It appears to be fairly stable in soil. Its morphogenetic activity could be detected 60 days after application.