There seems to be a concern that we may get caught with our booms down when we eventually do need to treat for Asian rust. In an attempt to be prepared, we sometimes willingly buy whatever product is "best promoted" to do the job. Researchers across the country are still busy determining just what to promote to do the best job.

It turns out that the number one strategy to promote for good efficacy from the application of herbicides as well as fungicides is not a specific product, but good knowledge; e.g. knowledge of the correct droplet size, of a method to choose an appropriate nozzle, of good calibration, and proper boom height.

There are some relatively exotic or fancy nozzle configurations that can appear to have a corner on the market for applying fungicides for Asian rust. The research, however, does not yet clearly point to any single nozzle or nozzle configuration that is guaranteed to work best. Yet, there are probably more than a dozen nozzles and maybe two dozen nozzles that will provide good coverage of the inside and lower portions of the canopy.

Ordinary single nozzles of the turbo and extended range varieties will work just fine for applying fungicides. However, it is important to choose a nozzle that will produce a medium to fine droplet for applying fungicides (refer to MU publication G1270). Very fine droplets will not do a better job because they will tend to drift off rather than reach the target. It’s also important not to skimp on water. Twenty gallons is typically recommended.

Finally, remember that for the application of any pesticide, the information on the label supersedes anything you might read in this newsletter. It’s not just good advice. It’s the law. And as always, wear good personal protective equipment and be safe.

Bill Casady
(573) 882-4370