The Egyptian cotton leaf worm, Spodoptera littoralis Bosid, (Lepidoptera: Noctuidae) is a polyphagous, foliage feeding insect and considered as one of the most serious pests of many different Egyptian crops (Magd El- Din & El-Gengaihi, 2000). It is an important pest of cotton in Africa, Middle East and Southern Europe (Hosny et al., 1986). Therefore, one single larva is able to destroy 66 cm2 of cotton leaves (Scarpellini, 2001). Also, it is widely distributed in the Mediterranean region, Africa, Asia and Europe (El-AW, 2006).
Many control methods were carried out to suppress the pest population and keep it under the economic injury level. The recent intensive research is concerned mainly with avoiding the serious problems resulted from using harmful insecticides that cause harmful residues in the food chain and pollution of the surrounding natural enemies and pest resistance (Salwa et al., 2001).
Therefore, now it has become necessary to search for alternative means of pest control which can minimize the use of these synthetic chemicals
(Abo-Arab and Salem, 2005). Also, to prevent the resistance phenomenon,
there is a need for different compounds having different modes of action
(Aydin and Gurkan, 2006).
Nowadays, the scientists of pest control and environmental protection
oriented their activities to control or at least to limit the environmental
pollution. Alternative pest control methods represent the major target of
many research programs all over the world because of its impact on
decreasing the manipulation of pesticides which led to environmental
pollution (Ragab and Ismail, 2001).
The necessity to find environmentally safe insecticides as well as materials to combat species resistant to conventional pesticides has spurred increased interest in alternative insecticides such as utilization of plant extraction and insect growth regulators (IGRs) which are currently evaluated for insecticidal efficacy, IGRs are considered to have little human toxicity, because humans do not make chitin and do not make or use the hormones
insects use in moulting (Schmutterer, 1985).
The use of IGRs compounds in insect control is known as insect developmental inhibition, which inhibits or prevents normal metamorphosis of immature stages to the adult stage. These compounds have been tested successfully against several insect species (Abdel-Aal, 2003; Moftah et al., 2004; Pineda et al., 2007; Bakr et al., 2009 ; Nehad et al.,2009 and Wang &Tian 2009 ).
Chitin synthesis inhibitors (CSIs) interfere with chitin biosynthesis in insects (Gijswijt et al., 1979) and thus prevents moulting or produces an imperfect cuticle (Hammock and Quistad, 1981). These compounds are effective suppressors of development for the entire life cycle on insects (Verloop and Ferrell, 1977). However, these compounds, also, affect the hormonal balance in insects, thereby resulting in physiological disturbances (DeLoach et...