Controle da mosca-da-haste [Melanagromyza sojae (Zehntner, 1900) (Diptera: Agromyzidae)] na soja com inseticidas via tratamento de semente

Abstract

The soybean stem fly (Melanagromyza sojae) (Diptera: Agromyzidae) is an insect pest that poses economic risks to soybean cultivation in Brazil and other South American countries colonized by this species. Initially contained within the northwestern region of Rio Grande do Sul state and in late-season soybean crops, M. sojae has expanded its occurrence to other regions of the state and country, including early-season soybean crops. There are many questions left to be studied about its management, especially concerning control methods using biological and chemical products, as well as genetic tools. Because the damage caused by M. sojae is barely visible and occurs within the soybean plants, its management becomes even more challenging. Biological control is a management technique that has been increasingly used, although it is still little explored for M. sojae. Thus, this work evaluated the control efficiency of biologicals and chemicals insecticides applied as seed treatment, through the use of two different entomopathogenic fungi: Beauveria bassiana and Metarhizium anisopliae, in addition to chemical insecticides composed of Caixa Vigor Praga ® (200 Ml of Cruiser 350 + 100 Ml of Fipronil + 100 Ml of Maxim XL). The treatments were analyzed together (chemical + biological) and also separately. The biological treatment, not yet commercially explored in the management of M. sojae, did not present satisfactory control efficiency when used in isolation, showing results similar to the control plot. The chemical treatment, on the other hand, showed positive results in the first evaluations, possibly because of its systemic action and residual effect. Therefore, seed treatment using chemicals is a viable tool to control M. sojae and protect soybean plants during the early development stages, which are the most susceptible to stem fly damage.