Efficiency of four bioinsecticides and their combinations with chlorpyrifos as a new approach for integrated management of Spodoptera littoralis

The efficiency of four bioinsecticides; XenTari, Rokur, Ecotech Bio and Dipel-2X applied at recommended rate and their combinations with insecticide, chlorpyrifos at 0.25 and 0.5 of its rate alone, compared with chlorpyrifos at 0.25, 0.5 and I of recommended rate, was investigated against the cotton leafworm, Spodoptera littoralis. The results showed that the synthetic insecticide chlorpyrifos with all tested concentrations was rapid at zero time. The mixtures of 0.5 and 0.25 fold of recommended dose of chlorpyrifos gave less LT50 values compared to each bioinsecticide alone. The activity of chlorpyrifos appeared and disappeared rapidly with the time. To kill 95% of second and fourth instar larvae after 24h feeding by pretreated cotton leaves, needs about 36 hours for chlorpyrifos alone while about 6 days for Dipel-2X and Ecotech Bio and 10 days for other tested bioinsecticides. 'Ihe bioinsecticides Ecotech Bio alone and DipeI-2X alone were statistically lowest active. Although, the cömbination of Ecotech Bio with chlorpyrifos and DipeI-2X with chlorpyrifos at 0.5 and 0.25 its rate were highest active treatments against fourth instar larvae. Mixtures of DipeI-2X and Ecotech Bio with chlorpyrifos at 0.25 of its rate or XenTari and Rokur with chlorpyrifos at 0.5 its rate can be integrated in IPM programm of cotton.