Controlled-release alginate-bentonite polymer gel granules of emamectin benzoate and control efficacy against Spodoptera frugiperda.

ABSTRACT

BACKGROUND: The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is known to cause large agricultural production losses. Emamectin benzoate is one of the most effective insecticides to control this pest; however, its effective time is not sufficiently long to control FAW. Therefore, it is important that new controlled insecticide formulations with new application methods are developed. RESULTS: A series of emamectin benzoate polymer gel granules were prepared with sizes ranging from 0.95 to 1.5 mm. As the bentonite content increased, the release rate decreased. The cumulative release process of emamectin benzoate mainly depends on the cracks in the surface of the granules, and the release rate can be described by non-Fickian and Fickian diffusion, which are closely related to the water content. By spreading the developed polymer gel granules into maize leaf whorls, the control effect reached 83% after 21 days in field trials. CONCLUSION: A novel polymer gel granule was developed that can effectively regulate emamectin benzoate release. By broadcasting polymer gel granules into maize leaf whorls, significant control efficacy against FAW can be obtained, and this could potentially be used for the effective control of FAW. © 2022 Society of Chemical Industry.