Drift Comparisons Between Aerial and Ground Orchard Application

Abstract

Applications of carbaryl, captan, or both were made by fixed-wing aircraft and by low-volume ground air blast sprayer to the same orchard site. Over the course of 2 years, a total of eight applications was made, four by air and four by ground equipment. The effect of two climatic parameters was evaluated. The first was under relatively calm conditions with a temperature inversion present and the second without a temperature inversion and with wind movement up to 12.9 km/h. Regardless of wind or atmosphere stability, carbaryl deposits from aerial application were found at the furthest sampling distance (500 m downwind). Ground applications under similar conditions left deposits at 150 m during a temperature inversion but provided no detectable levels at 50 m or further in the absence of an inversion. Differences between captan drift were not as clearly defined; generally, captan did not appear to drift as readily as carbaryl.