Attachment_8_-_ASABE_Standard_572_1_Droplet_Size_Classification.pdf

This document is an informational resource describing the ASABE S572.1 standard for droplet size classification in agricultural spray applications. The ASABE S572.1 standard establishes eight droplet classification categories to measure and interpret spray quality from spray tips, with six categories commonly used in agriculture and horticulture: Very Fine, Fine, Medium, Coarse, Very Coarse, and Extremely Coarse.

The standard uses Volume Median Diameter (VMD) measured in microns to classify droplets, ranging from less than 60 microns for Extremely Fine sprays to greater than 665 microns for Ultra Coarse sprays. Each classification category is associated with specific characteristics including color codes, retention on difficult-to-wet leaves, and primary applications. Fine sprays provide enhanced retention for directed spraying and are used for foliar-acting weed control and contact fungicides/insecticides. Medium sprays are the most widely used type for systemic-acting fungicides, insecticides, and herbicides. Coarse sprays are employed with systemic, residual, and soil-applied herbicides. The document includes a detailed reference table correlating droplet size to relative size comparisons (ranging from point of a needle at 25 microns to #2 pencil lead at 2000 microns) and provides guidance that spray quality selection should always be based on pesticide label requirements. Drift potential generally decreases as droplet size increases, with fine and medium sprays producing smaller, wider-angle droplets compared to coarse sprays that produce larger droplets.