Just curious if anyone has any experience with lower water volumes and fungicides. Local spray plane sprays 2 gal/acre and charges a dollar more than ground which will spray up to 20 gal/acre reluctantly. I have used the plane in the past and it seems to work ok at 2 but i asked about spraying 4 gallons and rate almost doubled in price. I never done any trials but wondering if anyone else has and what your thoughts are. I usually hire the plane for some acres just to keep him around but i would still like to know if im getting value from the fungicide at the low rate?
I spray my own fungicide with a ground rig but I try to let mother nature put the water on for me. If I can spray in a super dewey morning, then I cut back to 10 gpa. I use a good sticking agent like APSA 80 or Rainfast, so theres no runoff. If leaves are bone dry, then I go to 13-15, depending on field size. Have had good success so far
I think with the plane the conditions are more important than the water volume. I wouldn't allow spraying in a hot or windy day but have had the plane spray some on a calm evening several years ago and it gave excellent coverage at probably similar water rates.
Having said that I do all my own spraying if possible, usually contact herbicides and fungicides at 9.2 GPA because that's 120 acres on the 1100 gallon tank. Usually run at close to 100PSI through air induction nozzles and the coverage is excellent. Again I will shut down mid-day if it's hot or windy.
If you need penetration of the canopy with a fungicide like getting to the bottom of a lentil for anthracnose protection, then a ground rig with lots of water is the only way. I would take a high clearance any day over a plane unless it is too wet. Planes charge a lot for a poor job.