Agrotis ipsilon, known as the thread caterpillar, is a pest insect that can lead to total losses in agriculture, affecting a myriad of crops of economic importance for Brazil and the world. Studies aiming to curb the action of agricultural pests have led to the development of different forms of management, including the synthesis and use of chemicals, this being the most widely used management method to combat A. ipsilon and other pests. However, the excessive use of agrochemicals brings disadvantages, such as problems for human and environmental health, morphological defects in seeds and resistance of target organisms. Among the possible alternatives, the use of biocontrol with the use of entomopathogenic fungi stands out, because they are effective regarding the power of action on the target insect and environmental safety. Some species of Aspergillus have proven entomopathogenic potential, however, there is no test of its action on A. ipsilon in the literature. Therefore, thisstudy verified the specificity and bioinsecticidal potential of the isolate Aspergillus sp. NA01 on A. ipsilon.