Influence of Temperature and Humidity on the Incidence of Certain Pests of Cauliflower

摘要

Afield experiment was conducted to study the seasonal incidence of tobacco caterpillar, Spodoptera litura (Fab.), diamondback moth, Plutella xylostella (Linn.)'and aphid Brevicoryne brassicae (Linn.) on cauliflower at Agricultural College Farm, Bapatla during rabi, 2008-09. The incidence was recorded at weekly intervals from a total of fourty plants from four different locations ih the field. The peak incidence of S. litura (21.0 larvae/10 plants) on cauliflower was noticed during the last week of December, 2008, while in case of P. xylostella (17.2 larvae/10 plants) it was during the first week of January, 2009 and B. brassicae (18.3 aphids/10 plants) was during the first week of January, 2009. The relationship between the populations of S. lituralarvae and the aphids, and the morning relative humidity was negative but significant. Where as the relationship between the P. xylostella larval population arid, the morning relative humidity and maximum temperature was significantly positive and negative, respectively. '