Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz
Journal of Plant Diseases and Protection
109 (1), 57-63, 2002, ISSN 0340-8159
We evaluated the efficacy of commercial formulations of neem (Azadirachta indica) extracts against the
two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), on tomatoes and compared them
with the synthetic acaricide, amitraz. The neem formulations showed variable levels of protection of
tomatoes against infestation by T. urticae. Neemroc EC was the most effective and the level of
protection was comparable to that of amitraz. The neem formulations, except Neemros WP, showed
strong ovipositional deterrence of T. urticae and suppressed the emergence of nymphs on treated leaf
discs. Repeated application of the neem formulations and amitraz led to significant reduction of the
population size of mites on tomatoes, compared to the control. However, Neemroc EC was the most
effective in reducing leaf damage, whereas Saroneem, Neemroc Combi and Neemros WP-treated
tomatoes had high leaf damage ratings associated with lower fruit weight. The high performance of
Neemroc EC is attributed to the oil content in this formulation, particularly when compared with
Neemroc WP whose concentration of azadirachtin was very high and yet the effectiveness against mites
was very low. Neemroc EC was as effective as the standard and therefore an alternative to amitraz for
protecting tomatoes against infestation by T. urticae.