Field evaluation of entomopathogenic fungi formulations against Rachiplusia nu (Lepidoptera: Noctuidae) in soybean crop

Abstract

Rachiplusia nu (Lepidoptera: Noctuidae) is the main soybean plague in Argentina. The main strategy employed to control this pest is chemical control, applying different chemical groups regardless of their harmful effects on the environment and human health. Different biological products using entomopathogenic fungi have been developed and are commercially available to control different insect pests worldwide. The objective of this work is to develop and apply, under field conditions, different fungal formulations using entomopathogenic fungi to control R. nu larvae. The mortality percentages in bioassays of R. nu larvae treated with different colonies of fungal entomopathogens ranged between 86.6 ± 8.4% for Beauveria bassiana (LPSc 1098) and 56.6 ± 4.2% for Metarhizium anisopliae (LPSc 907). Under laboratory conditions using fungal formulations of B. bassiana, the formulation 4 (LPSc 1086) exhibited the highest mortality percentage (100%), followed by formulation 5 (LPSc 1098), 97 ± 1.3%. Under field conditions, larval mortalities were (82.4 ± 5.56%) for formulation F4 and (61.8 ± 7.5%) for formulation F5. The results obtained in this work indicate that although a greater number of tests under field conditions with the fungal formulation F4 are necessary, the results obtained in this work allow speculating that it is possible to use this fungal formulation under field conditions to control R. nu.