The Pathogens of Diamondback Moth and Their Potential for its Control a Review

The larvae and less frequently the pupae of Plutella xylostella (L) are sometimes attacked naturally by pathogens, particularly two fungi of the family Entomophthoraceae, Erynia blunckii and Zoophthora radicans. Other pathogens recorded include one other entomophthoraceous fungus, a granulosis virus, one or possibly two nucleopolyhedrosis viruses and Bacillus thuringiensis var kurstaki. In the laboratory, larvae were also susceptible to strains of several deuteromycete fungi, other nucleopolyhedrosis viruses and several varieties of B. thuringiensis. Of these pathogens, only B. thuringiensis is produced commercially and the derived products are used to control P. xylostella in the field. The bacterium, however, spreads inefficiently between host individuals and for effective control, as with chemical insecticides, repeated applications are necessary. Laboratory tests indicate that E. blunckii, Z. radicans, some of the deuteromycetes and certain viruses, all of which spread readily between individuals, may have potential as control agents. While none of these is produced commercially, methods for their mass cultivation are available though they need development. For each of these pathogens further laboratory and field trials are needed to select the most infective strains and to test application methods and formulations.