IMPACT OF PLANTING DATES ON INFESTATION OF COWPEA PLANTS WITH SOME PESTS

Abstract

Two years of field studies were carried out to study the effect of three planting dates of cowpea, April 1, 15e and 302', on the levels of infestation by different pests, namely: Tebanychus urticae, Tetranychus cuartbitacearum and whitefly, BemrSis tabad as well as Thdps fated. Also, the resultant yield was recorded. Data revealed that the numbers of different stages of T urticae were Increased by delaying the planting date on cowpea plants. Plant cultivated on April, 12, 152' and 30`2 harbored 0.48, 1.40 and 2.15 eggs, 0.42, 0.72 and 1.31 mobiles, 0.90, 2.11 and 3.46 totals / leaflet, respectively. The earliest planting date harbored the fewest mean number of T. cuarrbilacearurn, eggs, mobiles and total (0.40, 0.03 and 0.43/leaflet, respectively). Lately sowing correlated with plants showed the lowest infestation by different stages of white fly, B. tabad (0.33 (eggs/leaflet), 0.12 (nymphs/leaflet) and 0.04 (pupae/leaflet), 0.03 (adult/plant) and 0.51 (individuals of total stages)). The results induded that the abundance of Thrips tabad individuals increased only in the early planting date, mean rates of infestation in two seasons were (0.06, 0.05 and 0.02 nymphs, 0.01, 0.01 and 0.00 adult, 0.06, 0.05 and 0.02 individuals of total stages/leaflet respectively). Finally, the sowing in the earliest date (April, 12) lead to have the highest dry pods' yield and the lowest infestation by the spider mites, T. urtkae & T. cucurbtlaoaarum.