MISTURAS BINÁRIAS ENTRE Beauveria bassiana E SILICATO DE POTÁSSIO PARA CONTROLE DE Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) APONTAM SEU POTENCIAL SINÉRGICO, SOB CONDIÇÕES DE CAMPO

Abstract

Species of the order Thysanoptera may transmit irreversible tospoviroses to the tomato, provoking the symptom known as tomato spotted wilt. These insects are adapted to tomato crops in the tropics and are a key pest in tomato plantations for industrial processing in the state of Goiás, Brazil. Cases of resistance to insecticides indicate that the management of thrips should be urgently rethought in commercial crops. Research on the potential of new thrips control tools can clarify techniques most appropriate to the Integrated Pest Management philosophy. The objective was to evaluate the control efficiency (CE%) in Frankliniella occidentalis (Thysanoptera: Thripidae) by spraying the fungus Beauveria bassiana (Bb), the resistance inducer Potassium Silicate (SilK) and the Polytrin insecticide in isolation, or through binary mixtures, in two areas of tomato production in the state of Goiás, located in the municipalities of Pires do Rio and Orizona. The application of the isolated treatments (1) Bb, (2) SilK and (3) Polytrin or in binary mixtures (4) Bb+SilK, (5) Polytrin+SilK, and (6) Bb+Polytrin occurred by means of an experimental design type DBC with four replicates. The control treatment was SilK for reasons presented in the discussion. Samples of the thrips in white plastic trays occurred at 0, 1, 7 and 14 days after application of the treatments. The CE% of each product (and combination between them) differed at all time intervals evaluated in both areas. The Bb+SilK treatment gave a higher CE% of Frankliniella occidentalis in tomato plants from 24 hours after application (95.00 ± 5.00% and 74.62 ± 1.62% for Pires do Rio and Orizona, respectively). This treatment maintained higher EC%, in both areas, until the end of the experimental period. In Pires do Rio and Orizona there was a linear response in the decrease of CE% for Bb+Polytrin. Only in Orizona, Polytrin insecticide presented linear decreasing responses to EC%. Cluster analyzes indicated that Bb and SilK, each considered in isolation, were totally homogeneous among them in both areas. When in binary mixture, Bb+SilK showed greater heterogeneity compared to all other treatments. Evidence on the synergism between Bb and Silk is pointed out with great perspectives for use in Integrated Pest Management programs in tomato plants for industrial processing.