Improved Plant based Formulations for preventing Phthorimaea operculella damage on Stored Potatoes - Plantmix I and Plantmix II

Two formulations made from plant products, containing two constituents viz. Neemrich I + oil of Salvadora oleoides and Neemrich I + neem extractive, and named as Plantmix I and Plantmix II respectively were examined for oviposition deterrence (OD) and antifeedant (AF) activity against Phthorimaea operculella (potato tuber moth). Both the formulations showed greater activity than their individual constituents. Plantmix I and II exhibited 30 and 18 d persistence of 100% OD activity, compared to 12 d persistence of OD shown by the individual constituents at the lowest did tested. Greater AF activity has also been exhibited by Plantmix I, while Plantmix 11 did not exhibit any antifeedant activity. Nimbin was taken as a standard compound. This did not show significant OD or AF activity at the test dose. Plantmix I therefore stands out as a considerable improvement over neemrich I for preventing potato tuber moth infestation of stored potatoes.