Diamondback Moth, Plutella xylostella (L.), control studies on cabbage in St. Kitts

Diamondback moth (DBM) (Plutella xylostella (L.» insecticide efficacy and population dynamics studies were conducted in 51. Kitts 1985 1987. Experiment station and "on-farm" trials were conducted in addition to monitoring small farmers cabbage crops for DBM and Apanteles plutellae population levels. Pennethrin, Bacillus' thuringiensis (Berliner), and pirimiphos-methyl, controlled DaM adequately. Peaks in A. plutellae parasitism coincided with a predominance of 4th instar larvae. The presence of high parasite populations delayed the time to first spray. A relative growth rate analysis of DBM populations indicated that growth rates are correlated to percent A. plutellae parasitism. It is hypothesized that parasitism levels exceeding 25-35% may control DBM populations.