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ARS Home » Southeast Area » Stoneville, Mississippi » Pollinator Health in Southern Crop Ecosystems Research » Research » Publications at this Location » Publication #412323
Research Project: Ecological Assessment and Mitigation Strategies to Reduce the Risks of Bees to Stressors in Southern Crop Ecosystems

Location: Pollinator Health in Southern Crop Ecosystems Research

Title: Adjuvants for drone-based aerial pesticide applications to reduce pesticide drift and protect insect pollinators

Author
item Kannan, Narayanan
item Martin, Daniel - Dan
item SRINIVASIN, RAJANI - Tarleton State University
item Zhang, Weiqiang

Submitted to: Drones
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2024
Publication Date: 11/11/2024
Citation: Kannan, N., Martin, D.E., Srinivasin, R., Zhang, W. 2024. Adjuvants for drone-based aerial pesticide applications to reduce pesticide drift and protect insect pollinators. Drones. 8,667. https://doi.org/10.3390/drones8110667.
DOI: https://doi.org/10.3390/drones8110667

Interpretive Summary: Off-target drift from aerial pesticide applications in croplands is a major source of pesticide ex-posure to pollinating insects. Pesticide Adjuvants (PAs) are added to the tank mix to improve spray characteristics. Previous studies have pointed out PAs could be as toxic as the pesticide active ingredients. PAs with plant-based polymers appear to be less toxic to pollinators. Our ongoing experiments have identified sodium alginate (SA) as a less toxic drift-reducing PA. Hence, SA and Fenugreek polymer (FP) have been tested as drift-reducing PAs for drone-based aerial applications. Two spray experiments were carried out in the field: (i) water only (W) and (ii) water and adjuvant (WA). The drift reduction potentials (DRPs) of the adjuvants were analyzed based on droplet size and the proportion of driftable droplets (less than 150 µm size). Compared to those in the W only, the W-A treatment produced larger droplets, suggesting drift reduction. There were 46%, 28% to 29%, and 21% to 28% driftable droplets in the W, WA (SA) and WA (FP) treatments, respectively. Compared with the W only (2.7%), the FP treatment improved the on-target coverage (3.0% to 3.1%) that is highly desirable to improve spray application efficiency. Our results indicate that SA and FP have significant potential to reduce off-target drift and protect pollinator health.

Technical Abstract: Off-target drift from aerial pesticide applications in croplands is a major source of pesticide ex-posure to pollinating insects. Pesticide Adjuvants (PAs) added to pesticides to improve spray characteristics, could be as toxic as pesticide active ingredients. PAs with plant-based polymers appear to be less toxic to pollinators. Ongoing experiments have identified sodium alginate (SA) as a less toxic drift-reducing PA. Hence, SA and Fenugreek polymer (FP) have been tested as drift-reducing PAs for drone-based aerial applications. Two spray experiments were carried out in the field: (i) water only (W) and (ii) water and adjuvant (WA). The drift reduction potentials (DRPs) of the adjuvants were analyzed based on droplet size (diameters of 10%, 50% and 90% volume) and the proportion of droplets less than 150 µm. Compared to those in the W only, the W-A treatment produced larger droplets, suggesting the presence of DRP. There were 46%, 28% to 29%, and 21% to 28% driftable fines in the W, WA (SA) and WA (FP) treatments, respectively. Compared with the W only (2.7%), the FP treatment improved the on-target coverage (3.0% to 3.1%). Our results indicate that SA and FP have significant potential to mitigate off-target drift and protect pollinator health.