Efficacy of different rates and frequency of application of a neem based product, Aza-Direct, on leafminer, Liriomyza trifolii (Burgess), activity on snap bean

The leafminer, Liriomyza trifolii (Burgess) is a polyphytophagous pest of greenhouse crops and ornamentals that has developed resistance to most synthetic insecticides. The bio-insecticidal property of commercial neem product, Aza-Direct (1.2% azadirachtin) was evaluated against L. trifolii on snap beans. Three different rates 15, 25, and 35 oz per 100 gallons of water were used as foliar application. Three different frequencies of application were made for each product rate on a weekly interval. Number of mines, larval mortality and pupal mortality were assessed to determine the efficacy of the neem product. Larval mortality was high (80 to 100 %) when multiple application was done with all three rates. Aza-Direct applied once was only effective at higher concentration (25 and 35 oz/100 gallons) with 60 to 90 percent mortality of larvae, respectively. All treatments showed significant effect on pupal mortality (100%) regardless of the rate and frequency of application used. The neem product was effective for over one week when three applications were made with the high rate. This bio-pesticide did not show a consistent significant effect on leafminer activity after one week. Aza-Direct did not show any phytotoxic effect on snap beans at the rates and frequencies of application used in this study. The results indicate that foliar application of Aza-Direct causes substantial mortality of L. trifolii and can be recommended for management of leafminer in snap beans.