Determination of host parasitoid ratio for diamond back moth plutella xylostella (linnaeus) and its parasitoid cotesia vestalis haliday

The In vitro studies were carried out at 26+1oC and 65% to determine the optimum host-parasitoid ratio for the diamondback moth, Plutella xylostella and its endolarval parasitoid Cotesia vestalis. A single female of C, vestalis has the potential to parasitise 100 larvae effectively with 80.0 to 86.0 % parasitism, during an average female longevity of 12.9 days. The mean adult emergence was 88.56%, Mass production of the parasitoid would therefore be more effective with a host parasitoid ratio of 100 larvae : 1 female parasitoid. Field evaluation of the ratio would determine the dosage for inundative releases of the parasitoid for effective suppression of Plutella xylostella.