EFFECT OF CERTAIN CULTURAL PRACTICES ON THE POPULATION DENSITY OF EPILACHNA CHRYSOMELINA F. (COLEOPTERA-COCCINELLIDAE) AT THE NEW VALLEY GOVERNORATE IN EGYPT

Field experiments were carried out to study the effect of three cucurbit crops, five planting dates and three levels of fertilization rates on the population densities of Epilachna chrysomelina F. (Coleoptera: Coccinellidae) during 2007and 2008seasons. The results indicated that, the two variables (cucurbit crops and planting dates) had pronounced effects on the numbers of E. chrysomelina on cucurbit plants. Regardless the effect of planting dates and fertilizer rates, sweet melon was more susceptible to the E. chrysomelina infestation than cantaloupe and watermelon harboring the highest population of the pest (75.95 and 105.73 individuals / m2) during 2007and2008 seasons, respectively. Cucurbit plants cultivated in the late times (end of May and August) harbored relatively higher number of E. chrysomelina (larva and adults). Meanwhile, the plants of the early planting dates (end of March, middle of April and beginning of May) harbored relatively lower numbers of the pest. Insignificant differences were found between the numbers of the pest on cucurbit crops under different levels of NPK rates during 2007 and 2008 seasons. In2007 season, the highest population densities of the pest were recorded on sweet melon plants (228.33, 152.67 and 143.00 individuals /m2) during the fourth planting date (end of May) when the plants received double recommended, check and recommended dose of NPK, respectively. During 2008 season, unfertilized sweet melon plants recorded the maximum number of the pest (296.33 individuals / m2) during the fourth planting date followed by cantaloupe plants (296.00 individuals / m2) when cultivated during the fifth planting date and received double recommended dose of NPK.