Effect of nozzles, application rates, and adjuvants on spray deposition in wheat crops

Abstract

The use of insecticides is common in pest management in wheat crops but may lead to higher production costs and environmental contamination. Therefore, a more comprehensive and uniform distribution of plant protection products in the desired target is recommended. The objective of this study is to evaluate the effect of different spray nozzles, application rates, and adjuvants on droplet spectrum and spray deposition in wheat crops. The physicochemical characteristics of the spray mixture, droplet spectrum, and spray deposition in wheat plants were evaluated. The lower application rate (75 L ha-1) combined with the use of the twin flat fan tip AS7030 and the adjuvant sodium lauryl ether sulfate (SLES) yielded droplets with a larger diameter. However, insecticide spraying using hollow cone tip MGA 015 without adjuvants provided the highest percentage of droplets susceptible to drift. SLES significantly decreased the percentage of drift by increasing droplet size, and the adjuvant silicone, d-limonene, and polyester copolymer increased spray deposition. The evaluated adjuvants increased the electrical conductivity and reduced the surface tension of the spray mixtures. These results indicate that it is possible to reduce the application rate from 150 to 75 L ha-1 without affecting spray deposition on wheat leaves.