The distribution of ultra-low volume sprays from a light aircraft equipped with rotary atomizers

Abstract

As a preliminary basis to work on a method of chemical control of Australian plague locust nymphs, the influences of wind speed, emission height and droplet size on deposits of small insecticide droplets applied by a light aircraft equipped with Micronair rotary atomizers were investigated in a number of single-swathe trials. Deposits were sampled with small sensitive papers attached to the vegetation. The volume-median diameter of recovered droplets varied from 50 µm to 80 µm depending on the rotational speed of the atomizers. Results indicated that a strong wind (> 3 m s-1) would give good recovery of these small droplets, relatively uniform coverage and large swathe; but excessive drift could result if spray droplets were very small (60 µm) or if the emission height was too large (> 10 m).