Evaluation of a Laser-Guided Intelligent Sprayer for Disease and Insect Management on Grapes

Abstract

Background and goals New pesticide spray technologies are needed to replace inefficient conventional air-assisted practices for protecting grapes from diseases and insect pests. Methods and key findings A laser-guided intelligent sprayer was evaluated in an experimental vineyard for three consecutive growing seasons. Treatments included the intelligent sprayer with low (0.065 L/m 3 ) and high (0.13 L/ m 3 ) base spray deposition rates, and the conventional constant-rate application using the same sprayer but with the intelligent functions deactivated (935.4 L/ha). Evaluations included comparisons of spray coverage and deposition uniformity within vines, spray volume consumption, chemical cost savings, control of fungal diseases and Japanese beetles, and yields among the three treatments and nontreated plots as control. The conventional treatment consistently produced excessively higher spray coverage within vines than the low-and high-rate intelligent sprayer treatments, while spray deposition uniformity on grapevines did not differ significantly among treatments. Even though foliar disease severity was significantly higher in the intelligent low-rate treatment, marketable yields were not significantly different from either the intelligent high-rate or conventional constant-rate treatments; however, marketable yields in the intelligent low-rate treatment were 1.7 times higher than in nontreated plots. Japanese beetle incidence and herbivory varied significantly among treatments depending on sampling date, however, intelligent low-and high-rate treatments had significantly fewer beetles in the grapevine canopy than nontreated control plots for the majority of sampling periods each year. Furthermore, intelligent high-rate treatments suppressed Japanese beetles just as well as conventional air-assisted treatments. The intelligent spray treatments reduced spray volume by 29 to 83% compared to the conventional spray treatment, resulting in annual chemical savings of US$469 (high rate) and US$712 (low rate) per hectare. Conclusions and significance Intelligent sprayer technology could offer economically sustainable management of fungal and oomycete diseases and Japanese beetles for grape production.