Botanical extracts: additional tool for whitefly management in tomato

Resumo

Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) biotype B is one of the most limiting pests of tomato crops in the world. Tomato yield is currently dependent on the use of pesticides, which are problematic to producers, consumers and the environment. Insecticides of natural origin provide a promising alternative to reduce the harmful effects caused by the indiscriminate use of synthetic insecticides. This study evaluated the effect of 3% (w/v) aqueous extracts from different structures of thirteen botanical species on B. tabaci biotype B adults, as well as insecticidal activity of such aqueous extracts on B. tabaci eggs and nymphs infesting tomato plants. A distilled water solution and thiamethoxam insecticide (18 g/100 L of water) was used as a control. Leaf extract of T. ciliata was observed to have the most efficient inhibitory effect in tests of extracts on whitefly behavior. Furthermore, the use of leaf extract of T. ciliata led to the most drastic reduction in the number of adults and eggs on tomato leaflets. Leaf extract of P. aduncum led to the greatest observed ovicidal effect (78.00% of non-hatched nymphs), however it was not effective against nymphs and adults. The leaf extracts of T. pallida, T. casaretti, and Toona ciliata showed the highest control indexes (67.95, 60.27, 55.11%, respectively). For adults mortality, T. pallida was the most effective (72.80%). Our results indicate that application of extracts of T. pallida, T. ciliata, and T. casaretti are promising strategies to control B. tabaci biotype B on tomato.