Calibration Accuracy of Pesticide Application Equipment

Afield survey of 140 private and commercial pesticide applicators was conducted during the spring of 1986 in 12 counties of central and eastern Nebraska. The results showed that one out of every three cooperators was applying pesticides within ± 5% of their intended application rate. Results indicated that applicators have reduced application errors from that of a similar survey conducted in 1979. However, most errors still can be traced to incorrect calibration. Ninety-four percent of the cooperators used some type of calibration method. Two-thirds used the Known Area method. Those using a calibration method more than once a year had the fewest application errors. The commercial applicators had approximately 50% fewer errors in applying chemicals than private applicators. They also accounted for about twice the land area chemically treated of those sampled. Nozzle discharge uniformity was not a major problem suggesting that chemical applicators are changing nozzle tips more frequently than 8 years ago or more durable materials are being used