Comparing Greenhouse Handgun Delivery to Poinsettias by Spray Volume and Quality

Abstract

Insecticide and fungicide labels often lack specific recommendations on the spray volume and spray droplet sizes that will provide the most efficacious pest management of ornamental pest problems. A greenhouse trial was established to determine differences in spray retention in a poinsettia canopy between single-nozzle, handgun applications made using three different spray volumes and three different spray qualities. For the same areas of the canopy, there were few differences in spray deposit between treatments. Canopy position was a significant factor in the amount of spray found on foliar and artificial targets. Higher deposits were measured in the fronts and upper areas of the canopy than the backs and lower areas of the canopy. There were no significant differences in recovery of fungicide from leaves between treatments. The high-volume application produced the highest deposits on artificial targets across all spray qualities. There were no significant differences in overall spray deposit between the low- and medium-volume treatments.