Improved plant based formulations for preventing Phthorimaea operculella damage on stored potatoes - Plantmix I and Plantmix II.
The oviposition deterrent and antifeedant activity of 2 formulations containing Neemrich I + oil of Salvadora oleoides and Neemrich I + neem extract (Plantmix I and Plantmix II, respectively) were examined against Phthorimaea operculella. Both formulations showed greater activity than their individual constituents. The oviposition deterrent activity of Plantmix I and II continued for 30 and 18 days, respectively, compared to 12 days for the individual constituents at the lowest concentration tested. Plantmix I had the highest antifeedant activity while Plantmix II was inactive. Nimbin was taken as a standard compound and did not have significant oviposition deterrent or antifeedant activity. It was concluded that Plantmix I is a considerable improvement to Neemrich I for preventing infestations of P. operculella on stored potatoes.