Determining PGR Drench Rates

Growers are increasingly interested in drench applications of Piccolo, but the time required to test all crops for effective rates is excessive. We wanted to see if we could determine a ratio between effective Piccolo 10 XC spray and drench applications based on plant response. We also assessed the effect on flowering.

We evaluated growth responses of four crops. Two were sensitive to Piccolo 10 XC spray applications in previous experiments: Agastache ‘Tutti Frutti’ and Veronica longifolia ‘Pink Panther’ (vernalized) while two were not so sensitive in previous trials: Monarda didyma ‘Jacob Cline’ (vernalized) and Penstemon ‘Husker Red’ (vernalized). We applied a foliar spray application and compared the growth response of drenches applied at 5%, 10%, 20% or 40% of that spray rate (ppm).

Check out the video for our results. And decide if a “rule of thumb” based on effective spray rates would work as part of your PGR application strategy!