الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Cucurbit crops are considered one of the most important vegetable crops which used as a food in Egypt. Recently, a large sandy area was reclaimed and cultivated for years ago with different vegetable crops. Cucurbit crops under the present study are subjected to attack by a large range of insect pests such as aphids, thrips, whiteflies, and mealybugs which have a great economic importance and cause a serious damage. The host plant preference and sowing dates are essential components of integrated pest management (IPM) for different insect pests. Also, the snake cucumber beetle or the melon ladybird, Henosepilachna argus (Epilachna chrysomelina) (Geoffroy) is considered a serious insect pest of cucurbit crops in Egypt. Moreover, the different cucurbit crops are attacking with the twospotted spider mite, Tetranychus urticae Koch. which found as an economic pest infesting cucurbit plants in different planting dates. The two-spotted spider mite, Tetranychus urticae Koch is one of the most destructive pests. The divers host plant species may have been differentially affected by this pest. Cucurbit vegetable crops are commonly planted in numerous districts of Egypt affected by this pest. Cucurbit crops are preferable for this pest which decreases its yield. The rapid growth rate and high reproductive capacity of T. urticae allow it to cause higher damaging levels under suitable conditions, resulting in an equal decrease in host plant quality. Because of its short development and high reproductive fitness, it develops resistance faster than other insects. Studying the role of the natural enemies associated with these pests on different host plants and knowledge of the relationships between the pest and the natural enemy populations is fundamental basis for the integrated pest management program. Therefore, the objectives of the present investigations were to study the following points: Surveying the main pest attacking different cucurbit crops and their associated predators during two successive seasons, Studying the effect of different cucurbit crops on the population density of the main pest, Studying the influence of different cucurbit crops on the seasonal abundance of the main predators, Studying the impact of different cucurbit crops on the ratio between the main pests and their associated predators, Studying the impact of sowing dates on the population density of the main pests and their associated predators, Studying the effect of sowing dates on the relationship between the pests and their predators, Biological studies on the predacious phytoseiid mite, Amblyseius cucumeris (Oudemans) on different stages of the two-spotted spider mite, T. urticae as preys under laboratory conditions.