Pest Control: The Egyptian Cotton Leaf Worm

INTRODUCTION

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 res...

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... minutes. Homogenates were centrifuged at 3500 r.p.m for 10 minutes at 2C° in a refrigerated centrifuged. The supernatant can be used directly or stored at 5C° till used (Max. 2 weeks).

Acid phosphatase was determined according to the method described by Powell and Smith (1954).

Alpha esterases (α-esterases) and beta esterases (β-esterases) were determined according to the methods of Van Asperen (1962) using α-naphthyl acetate and β-naphthyl acetate as substrates, respectively.

Statistical analysis:

By using (Origen lab program version7.5) the data were expressed as means ± standard errors. The statistical significance of differences between individuals means were determined by using one way ANOVA test. Levels of significance of each experiment was stated to be significant at (P = 0.05), high significant at (P = 0.01) and very high significant at (P = 0.001).