Development and use of a biological control — IPM system for insect pests of crucifers

An effective biological control-integrated pest management (BC-IPM) system that maximizes biological control of Plutella xylostella (L.), Artogeia rapae (L.), and Trichoplusia ni Hubner) has been developed. In the first phase, chemical insecticides were replaced by the judicious use of the microbial insecticide Bacillus thuringiensis; there was an immediate reduction (>50%) in the number of treatment applications required. Technology and procedures for using parasitoid species for seasonal inoculations were developed; field tests established that a complex of several species of parasitoids increased parasitism, reduced pest populations, and resulted in market acceptable cabbage and broccoli crops. The system was successfully validated in several fields of commercial cabbage in the Rio Grande Valley of Texas; a commercial insectary produced, sold, and released the beneficial insects. A commercial BC-IPM system that emphasizes augmentative releases of Cotesia plutellae Kurdjumov on several hundred ha of broccoli and cauliflower has been in operation in Guatemala and Mexico for the past three years. A program to manage P. xylostella and other crucifer pests has recently been initiated in Mauritius. The initial focus is on the development of a population database and construction of a facility for production of P. xylostella and C. plutellae. An evaluation and implementation phase will concentrate on the augmentative releases of C. plutellae and the judicious use of B. thuringiensis. A later phase of the program will utilize the combination of inherited sterility and releases of C. plutellae to manage DBM populations.