Population dynamics of the cabbage butterfly Pieris rapae (Lepidoptera: Pieridae) and its control in cabbage at Fayoum Governorate

The present work was carried out at the Experimental Farm, Fac. of Agric., Fayoum Univ., and aimed to shed some light on populationfluctuations of the cabbage white butterfly, Pieris rapae L. (Lepidoptera: Pieridae), and its associated natural enemies and relation to some weather factors at Fayoum Governorate on cabbage (Brassica oleracea var. capitata L.) cultivated in four successive plantationsduring the 2019/2020 and 2020/2021 seasons. Natural enemies associated with P. rapae, are the lady beetle, Coccinella undecimpuncta L, (Coleoptera: Coccinellidae), the syrphid fly Episyrphus balteatus (De Geer) (Diptera: Syrphidae), and the braconid parasitoid, Diaeretiella rapae M’Intosh (Hymenoptera: Braconidae). Population fluctuations of P. rapae had one and two peaks in summer and winter plantations of the first season during 5th June, 16th December and mid-January, with 9, 15, and 14 individuals/30 leaves, respectively. In the 2nd season, its population recorded two and three peaks with 8, 7, 17, 18, and 22 individuals/30 leaves during 6th April, 5th June, 21st December, and 10th and 30th January for summer and winter plantations, respectively. The efficiency of bactericide (Dipel X) and chemical material (Runner 24% Sc) and plant extract used (garlic) were evaluated on P. rapae throughout the period. The results observed a high effect on populations P. rapae that treated by all used materials.