UTILIZAÇÃO DE DIFERENTES DOSAGENS DE CORDYCEPS JAVANICA SOBRE DIATRAEA SACCHARALIS DA CANA-DE-AÇÚCAR

Abstract

Sugarcane is one of Brazil's most important agricultural crops, fundamental for sugar and ethanol production, and economically vital to the country. However, the pest Diatraea saccharalis, known as the sugarcane borer, has a significant threat to the crop, causing direct damage to the stalk and facilitating the entry of opportunistic pathogens. To combat this pest, the entomopathogenic fungus Cordyceps javanica has been promising, particularly due to its effective use in controlling other pests, such as the spittlebug (Deois flavopicta). This study aims to evaluate the efficacy of C. javanica in different dosages for controlling D. saccharalis in sugarcane. Experiments were carried out at the Instituto Federal Goiano, Campus Iporá, using two application methods: spraying and immersion, under laboratory and greenhouse conditions. Aerial applications were performed at a rate of 30 L/ha for 1st and 3rd instar larvae, while ground applications used a rate of 120 L/ha, focusing on 1st instar larvae. The dosages ranged from 400 to 800 mL/ha. The data were subjected to statistical analysis, using arcsine transformation (x/100)^(1/2) and compared using Tukey’s test at a 5% probability level. Results showed that aerial spraying with 800 mL/ha of C. javanica was the most effective, achieving 100% mortality in 1st instar larvae and 88% in 3rd instar larvae. Aerial immersion also showed high efficacy in 1st instar larvae with 800 mL/ha but was less effective in 3rd instar larvae (84% mortality). On the other hand, ground immersion was ineffective in 1st instar larvae, while ground spraying with 600 mL/ha achieved 97% mortality. This study highlights the potential of C. javanica as an effective biological control agent against D. saccharalis, with significant implications for sustainable sugarcane management.