Distribution of Emamectin Benzoate Granules in Maize Plants by Broadcasting into Maize Leaf Whorls

Yujun Long; Haiyan Zhang; Guohui Liao; Minggui Chen; Xiangyan Chen; Lixin Qin; Caijun Chen; Zhuo Chen; Xiaomao Wu; Feng Zhu

doi:10.1021/acsomega.2c07402

Distribution of Emamectin Benzoate Granules in Maize Plants by Broadcasting into Maize Leaf Whorls

ACS Omega. 2023 Jan 16;8(4):4209-4219. doi: 10.1021/acsomega.2c07402. eCollection 2023 Jan 31.

Authors

Yujun Long^{1

2}, Haiyan Zhang², Guohui Liao², Minggui Chen², Xiangyan Chen², Lixin Qin², Caijun Chen², Zhuo Chen³, Xiaomao Wu¹, Feng Zhu^{2

3}

Affiliations

¹ Guizhou Key Laboratory of Mountain Agricultural Diseases and Insect Pests, Guizhou University, Guiyang550025, China.
² Guizhou Center for Pesticide Risk Monitoring, Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang550006, China.
³ State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang550025, China.

Abstract

Good control effects on fall armyworm (FAW) can be obtained by broadcasting emamectin benzoate (EB) granules into maize leaf whorls. However, the distribution of EB in maize plants is not clear. In this study, EB granules were prepared by the rotating granulation method, and the granules were characterized using a Fourier transform infrared spectrometer. The behavior of EB granules in water was observed using a microscope, and in vitro release of EB from granules was also studied. A method for the determination of EB in maize plants, old leaves, grains, and cobs was established by using ultra-performance liquid chromatography-tandem mass spectrometry. The results showed that EB was loaded in granules successfully, and the granules disintegrated slowly in water, so the release of granules could be regulated using various water contents. The prepared EB granules were qualified and stable. The field experiment showed that the concentration of EB in maize leaf whorls could be maintained above 0.23 mg·kg^-1 within 3 days after broadcasting EB granules. This ensured that FAW could be killed in a short time. Then, EB gradually transferred to the old leaves. After 21 days of application, the content of EB in the old leaves was 0.07 mg·kg^-1, which has long-time control effects on FAW. The control effects of the three doses of granules against Spodoptera frugiperda were higher than 78% after 14 days of application. At the tested dosage, no phytotoxicity to crops was observed. At harvest, neither the maize grain nor the cobs had EB content. New controlled formulations to S. frugiperda were developed and will be suitable for application in mountainous areas where the lack of water resources is a factor.