Article co-written with Jennifer Llewellyn, OMAFRA Nursery Crops Specialist.
Nursery growers apply pesticides to a diverse range of plant species. In a perfect world, sprayer operators would adjust their sprayer set-up to match each crop. Adjustments in product rate and spray distribution should reflect the plant size, row spacing and developmental stage of the crop and pest. It should NEVER be done without a reference point for coverage and a strong history of efficacy. This experiment demonstrates the value of customized application settings and their potential to conserve pesticide, water, and fuel without compromising pesticide efficacy.
Three 65m x 6.5m blocks were marked out in a field of roses in September, 2011. An untreated control, the grower’s traditional set up of hollow cones (D4D45) on 50 cm centres at 300 psi and 3.0 mph (841 L/ha), and an optimized set up of hollow cones (D3D45) on 50 cm centres at 150 psi and 3.0 mph (388 L/ha) (determined through trial and error using water-sensitive paper as a coverage indicator).
One application of Folpet + Nova was made on Sep 19, 2011. Roses were photographed before and after the treatment. The photographs were digitized and the amount of powdery mildew appearing on the upper surfaces was determined as a percent of the total leaf area. All reps were randomly selected.
There was no statistically significant difference in visible damage between the grower’s typical application set-up and the customized set-up. It was unclear why the control presented with less mildew eight days after application. The focal point here is that efficacy was maintained with optimized settings.
Nursery applicators should consider customizing sprayer settings for each crop using water sensitive paper to indicate suitable coverage. Adjusting application settings can.
The Ontario Farm Innovation Program and the grower co-operator are gratefully acknowledged for making this research possible.