A Simple Method for Identifying Sex of Plutella xylostella(Linnaeus)Larva, Pupa and Adult

Based on the morphological appearances and descriptions in literature,a simple and convenient method for identifying the sex of diamondback moth(DBM),Plutella xylostella(Linnaeus),was developed.The results showed that the sex of the first-and second-instar larvae was not easily distinguishable by naked eyes or optical microscopic observation.However,the male third-and fourth-instar larva showed a lighter colored fifth abdominal segment than that on the female counterparts.On the male pupae,a lump on each side of a short,longitudinal slip was visible near the gonopore on the 9th abdominal segment.The female pupae had a long,longitudinal slip between the genital pore on the 8th abdominal segment and the oviporus on the 9th segment.The adult males had characteristic brown wings with a wavy edge on the posterior margin and a yorked abdominal end.The female adults,on the other hand,were lighter in color and bigger on body size than the males,and had their abdominal ends appeared round in shape.