Help with spraying with new gas powered backpack sprayer

[HanksHill]

I've got a new-to-me Stihl SR200 now that my vines are getting bigger and canopies along with them - but I'm struggling with how much fungicide to apply through it. It can put out a really nice fine mist, but I'm afraid I'm not applying quite enough (it has a dial to control flow). I was used to a backpack sprayer where everything got "wet" in order to get decent enough coverage, to the point things sometimes dripped. I may have been applying too much. I just did a first spray on 3rd year vines, shoots ranging from a few leaves on a 1" shoot to shoots maybe 7-8" on some of the earlier budding varietals with mancozeb and sulfur and used about 1.3 gallons of mixture for 150 vines. Thoughts?

 

[Vern]

When I spray with my stihl it takes 3.5 gallons for 96 vines. They are wet but don't drip. Maybe you need to increase the valve.

 

[CTDrew]

I've got a new-to-me Stihl SR200 now that my vines are getting bigger and canopies along with them - but I'm struggling with how much fungicide to apply through it. It can put out a really nice fine mist, but I'm afraid I'm not applying quite enough (it has a dial to control flow). I was used to a backpack sprayer where everything got "wet" in order to get decent enough coverage, to the point things sometimes dripped. I may have been applying too much. I just did a first spray on 3rd year vines, shoots ranging from a few leaves on a 1" shoot to shoots maybe 7-8" on some of the earlier budding varietals with mancozeb and sulfur and used about 1.3 gallons of mixture for 150 vines. Thoughts?

I think sprayer calibration be helpful to you. You want to be sure you not only have the right amount of product in the right amount of water but also that that mix is covering the right amount of area. The manual here:

https://cdnassets.stihlusa.com/1625858022-stihl-sr-200-owners-instruction-manual.pdf

goes through how to do the calculations on pages 22-23. I am sure you could find videos on calibrating similar sprayers online. Hope this helps you sort it out.