ESTRATÉGIA DE MANEJO COM BIOINSUMOS PARA Dalbulus maidis, INCLUINDO EM PLANTAS NÃO HOSPEDEIRAS

Abstract

Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) generates losses in several types of corn produced in Brazil, due to the transmission of pathogens. Its quantity in agricultural plantations without its preferred hosts has increased, as in Solanaceae and Fabaceae. Chemical methods generate control of up to 90% but with a shortage of only seven days via seed treatment plus foliar applications. This low temporal efficiency can be useful for the integration of chemical and microbiological methods. A premise of Integrated Pest Management (IPM). Therefore, the parasitic fungi Beauveria bassiana (Bb), Metarhizium anisopliae (Ma) and Isaria fumosorosea (Isa) against Dalbulus maidis in pea plants (var. Gallant), under field conditions, was evaluated. Additionally, we investigated the performance of these fungi in mixture in the pre-application with the potassium silicate resistance inducer, including the productivity (kg ha-1) of that plant. The treatments were arranged through a factorial (3x2)+2, with three levels of Fungi factor (Bb, Ma or Isa), two levels of SilK factor (without and with potassium silicate) plus the addition of a control group: absolute one (water only) and a positive one with prophenophos+lufenurom. The leafhoppers were sampled by yellow adhesive traps at 0, 3, 6, 9 and 12 days after the treatment application. The mixture between SilK and entomopathogenic fungi increased the ability of these parasites to infect adults of Dalbulus maidis. But 85.63% of the corn leafhoppers sampled did not present fungal infection, suggesting that factors inherent to the architecture of the pea plant and climatic conditions may have contributed to these low infections, regardless of the fungal species evaluated. A greater number of infected maize leafhoppers were sampled in the plots with Isa than with Bb or Ma. The SilK resistance inducer has relevance in the fungus-host relationship investigated here. When we consider the significance of the isolated factor SilK, its absence was determinant for larger quantities of leafhoppers without infection sampled. And SilK presence increased the number of infected insects. This management with binary mixtures between fungi and SilK also increased pea plants yield.