Influência do silício na indução de resistência à mosca-branca Bemisia tabaci biótipo B (Genn.) (Hemiptera:Aleyrodidae) e no desenvolvimento vegetativo em dois cultivares de soja Glycine max (I.) Merrill

Abstract

The potential for resistant Bemisia tabaci populations to develop as a consequence of intensive use of chemical insecticides has stimulated studies on integrated pest management tactics, for example, the induction of host-plant resistance. Recent studies have shown that silicon can increase plant resistance against insects. The objectives of this work were the evaluation of resistance induction to the whitefly B. tabaci biotype B and the vegetative development of soybean plants, by silicon application. Free-choice and no-choice tests of oviposition preference had been carried on two soybean cultivars, IAC-19 (moderately resistant to insects) and MONSOY-8001 (susceptible). The number of eggs and nymphs of 3rd and/or 4th, phenolic compounds, lignin and non-proteic nitrogen production and dry weight of aerial parts and roots of the plants had been evaluated. Silicon did not affect whitefly oviposition preference; however, it caused greater mortality of nymphs. Moreover, silicon had decreased the production of phenolic compounds, did not affected lignin production, although when associated to cultivar IAC-19 it had increased the production of non-proteic nitrogen in soybean plants. Silicon did not affect the vegetative development of soybean plants and associated to cultivar IAC-19 it had increased the level of resistance to whitefly. In this way, the use of silicon in association to the cultivar IAC-19 can reduce significantly the populations of this whitefly, bringing positive reflexes to soybean crops and to the environment.