Distribution pattern of diamondback moth, Plutella xylostella (L.) on cabbage under Gangetic alluvial condition of West Bengal

Distribution pattern of diamondback moth larvae Plutella xylostella (L.) on cabbage (Brassica oleracea var. capitata L.) was studied under Gangetic Alluvial condition of West Bengal in three consecutive cabbage seasons (early cabbage, on season cabbage and late cabbage) during 2009-10. Various indices like dispersion parameter ‘K’, index of dispersion (Id),reciprocal of the exponent K, Cole’s Index, Charlier Coefficient, Lloyd index of mean crowding and Lloyd index of patchiness confirmed that the distribution pattern of the diamondback moth larvae under the study in three crop seasons was aggregative in nature.