Effects of bioinsecticide application on the control of Spodoptera frugiperda in the Marginal 28 variety (Zea mays L.), San Martín region, Peru

To reduce pest populations below the economic damage threshold, producers frequently and intensively use pesticides, often exclusively, contributing to soil contamination. The objective of this research was to evaluate the effects of bioinsecticide application on the incidence of fall armyworm (Spodoptera frugiperda J. E. Smith) in the Marginal 28 corn variety (Zea mays L.) in the San Martín region of Peru. The experiment was conducted at INIA's El Porvenir Agricultural Experimental Station, located in Juan Guerra, San Martín, Peru (06°35'50'' S, 76°19'30'' W), between October and December 2024. A completely randomized design (CRD) was used, with five treatments and 10 replicates. The tropical Marginal 28 seed was planted in 5 plots in the following treatments: (T1) - Control, (T2) - Coragen® 20SC - Clorantraniliprole, (T3) Beauveria bassiana, (T4) Best-K (Bacillus thuringiensis var. kurstaki) (T5) Best-A (Bacillus thuringiensis var. aizawai). Eight field evaluations were carried out before and after the application of the treatments, during the diagnostic period of the fall armyworm, using the Davis scale. Among the treatments, the one that obtained the lowest severity score was the chemical control (reduction of 71.5% in pest severity, compared to untreated plants), followed by the biological treatments Best-K and Beauveria bassiana (reductions of 45.4 and 28.2%, respectively). The use of bioinsecticides is a more sustainable and safer alternative for pest control, reducing environmental impact and contributing to increased production.