Comparative efficacy of Neem(Azadirachta indica) and Amitraz (Mitac) against the two spotted spider mites (Tetranychus Urticae), on Tomatoes (Lycopersicum esculentum)

Abstract

Various neem (Azadirachta indica. A. Juss) formulations were evaluated under laboratory and greenhouse conditions for their effects on two-spotted spider mites, Tetranychus urticae Koch (Prostigmata: Tetranychidae), on tomatoes, Lycopersicum esculentum. Four neem formulations (Neemros: neem seed powder with 0.5% azadirachtin, Neemroc: a water miscible emulsifiable concentrate oil, with 0.03% azadirachtin, Saroneem: an alcohol extract; extracted in isopropyl alcohol, containing 1% azadirachtin and Neemroc combi: an enriched oil extract with 0.5% azadirachtin) were tested against two-spotted spider mites. Mitac, an acaricide, was used as a standard in the tests. The effective lethal concentration for each formulation against spider mites was established and compared to Mitac as well as between the neem formulations. Mitac treatments were more effective than the neem formulations in protecting tomatoes against T. urticae. However, Mitac treatments had higher toxicity to predatory mites P. persimilis than neem treatments. neem formulation, Neemroc EC showed good protection comparable to that of Mitac against T. urticae. This treatmemt had a strong feeding inhibition, ovipositional repellence and mortality effect on mites. Saroneem and Neemroc combi gave low protection, although repell¥ce and feeding inhibitions were stronger. Neemros WP was not effective against two-spotted spider mites. Plants treated with Neemros WP, Saroneem and Neemroc combi, had short residual effect compared to Neemroc and Mitac treatments on tomatoes. A significantly higher tomato yield (weight) was generally observed among treatments compared to the control. Untreated control without mites and Neemroc EC treated plants had higher fruits yield by weight followed by Mitac treated plants. Neem treated plants (Neemros, Saroneem and Neemroc combi) had significantly less fruit yield. Untreated control plants with mites had significantly low fruits yield. The study generally shows that there is potential for using neem formulations to control two-spotted spider mite in tomatoes. The neem oil formulation Neemroc EC provided better protection almost like that of Mitac.