Metodologia de criação de Bemisia tabaci (Gennadius) biótipo B (Hemiptera: Aleyrodidae) e seu controle em cultivos protegidos

Abstract

The method of greenhouse cultivation, or protected cultivation, has been increasing due to good research in times of lower product supply, better control of adverse conditions and, consequently, better prices in the market. The whitefly Bemisia tabaci MEAM1 is one of the main pests present in this type of cultivation, requiring for its control a deep knowledge about its bioecology, as well as its management. Considering the importance of experiments with B. tabaci MEAM1, the aim was to define a mass rearing methodology for B. tabaci MEAM1, to evaluate the insecticide effect of botanical products on their natural enemies and to evaluate the effect of two baits on the attractiveness and permanence of natural enemy’s species of the whitefly. The research was conducted at the Laboratório de Entomologia Aplicada, belonging to the Faculdade de Ciências Agrárias da Universidade Federal da Grande Dourados, Dourados/MS, being divided into four chapters. Chapter I presented the state of the art of the studied points. In Chapter II, the experiments showed leafy cabbage and soybean, followed by cucumber and eggplant as suitable hosts for whitefly mass rearing, however the fertility life table indicated leafy cabbage as the best host according to the estimated parameters for RO = 252.20; T = 27.45; TD = 3.50; Rm = 0.198 and λ = 1.219. Correlation analyzes on mass rearing revealed plausible correlations of B. tabaci nymphs with a predatory coccinellid of the genus Delphastus, as well as parasitoids of the genus Encarsia. Thus, there are technique and methodological domain to massively create the whitefly B. tabaci MEAM1; D. argentinicus and Encarsia spp. are strongly correlated with the immature population of B. tabaci MEAM1 and require control. In Chapter III it was determined which products are effective in controlling B. tabaci MEAM1 in its nymphal stage and which are selective to natural enemies. After 24h, Benevia® had the highest nymph mortality recorded (100%), followed by castor oil (57.3%), eucalyptus oil (56.3%), garlic oil (45.6%) and Oberon (40.6%). At 48h only Orobor® and the control have the lowest mortality rates. In assessing selectivity to natural enemies, Benevia® was considered harmful to the predator D. argentinicus (85% mortality) and the parasitoid E. inaron (98% mortality); Eucalyptus oil was considered harmless to the predator (10% mortality) and slightly harmful to the parasitoid (26% mortality), while Orobor® was considered harmless to both. Thus, Benevia®, castor oil, eucalyptus oil, garlic oil, Oberon and Orobor® can be used to the control of third and fourth instar nymphs, and eucalyptus oil and Orobor®. may be used in conjunction with the predator and whitefly parasitoid in protected cultivation. In Chapter IV the effect of food and olfactory attractants on B. tabaci MEAM1 natural enemies was evaluated. No significant differences in parasitism rates were observed between the control and jasmine oil plants, however a lower parasitism rate was observed when honey + yeast was used as attractive. The application of jasmine oil provided the constant frequency of parasitoids in plants.