RESPONSE OF FOUR BRASSICA SEED CROP SPECIES TO ATTACK BY THE CRUCIFER FLEA BEETLE, PHYLLOTRETA CRUCIFERAE

Abstract

Apparent resistance to attack by the crucifer flea beetle in seedlings of Yellow mustard, Brassica juncea Moench, as opposed to the susceptibility of the mustard B. juncea (L.) and the rapeseed species B. napus L. and B. campestris L., was investigated in a field plot experiment in 1976, comprising insecticidally protected and unprotected treatments of each of the four species. Seedlings of unprotected B. hirta suffered little damage and final seed yields were as high as those from the protected treatment. The mustard B. juncea and the rapeseed species B. napus and B. campestris all suffered severe seedling damage when not protected. Nevertheless the unprotected B. juncea treatment yielded as much as the protected; B. napus, however, suffered an apparent appreciable decrease and B. campestris a significant decrease.