Question From: J. Gunter - Norman, Oklahoma, United States
Q: I am applying sulfur to peach trees (just 4) to help prevent spots and control some smaller insect pest. I used dormant oil the last week in January, and started with sulfur the first week in March, just before bud's broke. It occurred to me that I should maybe use a surfactant to get better coverage. The farm supply store has plenty of surfactant (I think it is called 'Surfactant 60'), but I am unsure if I should lower the concentration of the sulfur, if I can used the sulphur at "full strength" with the surfacant to get better coverage, or if I should forget the surfactant altogether. The directions on the package (that I can still read) do not recommend the use of a surfacant or against it. I see no indications of a wetting agent so I can't be sure one is included on the parts of the label that are still legible. The sulfur has directions to apply as a powder or to mix with water as a spray, so I suspect a wetting agent, but don't know for sure. I was going to mix a little in a quart sprayer and hit a branch budding out and see what happens over a week, but I'd though I'd see if you have any suggestions before I test it out. Do you have an educated answer to the question of would mixing surfactant with the wettable powdered sulfur to improve coverage will harm my trees, or have no impact. Won't hold you to it - just thought you may have had more experience with the issue. You can't even see the tree or site.
I do not as I have not used these products. I recommend you contact the manufacturers of the products. They all have 800 numbers. Susan Poizner in her book Growing Urban Orchards, suggests mixing the dormant oil with lime sulfur. The oil would work as a spreader sticker. Key is that you do all this spraying before green shows to prevent damage. Check out the OKU website http://www.oklahomagardening.okstate.edu/resources and enter care of peach trees for more information. Best And Happy Yardening, Nancy