EFFECT OF PLANTING DATES ON INFESTATIONS WITH CERTAIN PESTS AND YIELD PARAMETERES OF SQUASH PLANTS

Abstract

The effect of four planting dates of squash seeds (March, 15 th , April, 1 st , April, 15 th and May, 1 st ) on levels of infestation with three pests, aphid, Aphis gossypii Glover, whitefly, Bemisia tabaci (Genn.) and thrips, Thrips tabaci Lind. and on yield of this plant, were studied during two successive seasons (2009 and 2010). The degree of infestation by these pests increased significantly by delaying planting date, as squash plants cultivated in the earliest planting date (March, 15 th ) were attacked by the fewest numbers with highest weight of squash fruits, while the plants of the latest planting date (May, 1 st ) were more liable to insects infestation with lowest weight of squash fruits. The results showed that, the mean rate of infestation with A. gossypii were (2.82, 4.07, 17.27 and 30.78 individuals/leaf) during 2009 season, (0.28, 3.35, 9.04 and 13.27 individuals/leaf) during 2010 season for the four dates, respectively. So, the earliest date (March, 15 th ) led to plants harboured the lowest population of A. gossypii (2.82 and 0.28 individuals/leaf in the two seasons, respectively), also, the highest weight of squash fruits (9.39 and 10.89 kg/plot in the two seasons, respectively) was obtained. The same trend were recorded for the populations of B. tabaci and T. tabaci on squash plants during the two seasons. Therefore, it was concluded that, the plant date was effective on the rate of infestation with pests and yield of squash plants and can be avoided by planting it as early as March, 15 th