Seasonal Population Fluctuations of the Cabbage White Butterfly, Pieris rapae (Linnaeus, 1758) and Diamondback Moth, Plutella xylostella (Linnaeus, 1758) on Cauliflower Cultivars

Small cabbage white butterfly، Pieris rapae (L.) (L.) (Lep.: Pieridae) and diamondback moth، Plutella xylostella (L.) (Lep. Plutellidae) are two of the most important insect pests of the family Brassicaceae. Use of resistant varieties is suitable management strategy for control of these pests. In order to study the population fluctuations of P. rapae and P. xylostella، eight cultivars of cauliflower were planted in a completely randomized block design with five block and 40 plot at the Shahed University research field (south of Tehran) and a sampling was performed once every ten days. The highest total density of different stages of P. rapae was observed on Smilla and Dogol cultivars and the lowest density of total stages of this pest was observed on Abre-sefid and Tokita. The highest of the egg density of P. xylostella was observed on Smilla and Dogol cultivars and the lowest egg density was on Buris and Takgol cultivars. Larval and pupal density of P. xylostella on Smilla and Dogol cultivars was more than that on other cultivars.