Evaluation of a laser-guided intelligent sprayer for disease and insect management on grapes

Authors: WODZICKI, LIANNA - The Ohio State University; MADDEN, LAURENCE - The Ohio State University; LONG, ELIZABETH - The Ohio State University; Zhu, Heping; IVEY, MELANIE - The Ohio State University

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2023
Publication Date: 8/25/2023
Citation: Wodzicki, L.M., Madden, L.V., Long, E.Y., Zhu, H., Ivey, M.L. 2023. Evaluation of a laser-guided intelligent sprayer for disease and insect management on grapes. American Journal of Enology and Viticulture. 74. Article 0740024. https://doi.org/10.5344/ajev.2023.23013.
DOI: https://doi.org/10.5344/ajev.2023.23013

Interpretive Summary: Fungicide and insecticide applications can cost grape producers up to US$1,042 per hectare per season in an established vineyard. In addition, chemical wastes due to off target drift and ground drop-off of pesticides have caused negative consequences on human and animal health, and the environment. In this research, a laser-guided variable-rate intelligent sprayer was tested for its capability to manage foliar diseases and pest insects in vineyards. Severities of foliar diseases of downy mildew, black rot and Phomopsis leaf spot were rated and the incidences of Japanese beetles and associated herbivory were assessed. Marketable yields, pesticide consumptions and chemical savings were also documented and compared between the intelligent and conventional spray applications. The consecutive three-year tests demonstrated that the intelligent spray application delivered a uniform and targeted application to the grape vines, and reduced the volume of pesticide spray solutions by 29% to 83% without compromising foliar disease and Japanese beetle control or marketable yields. Direct and indirect benefits of such great reduction of pesticide use included: spraying more area of vineyards with a single tank chemicals, reducing the amount of time required to refill spray tanks, conserving water especially for drought-stricken areas, saving pesticide costs, and enhancing pesticide stewardship and public health safety. Thus, this validated intelligent spray technology would be an effective and sustainable approach for growers to manage foliar diseases and insect pests in the grape production.

Technical Abstract: Background and goals: New pesticide spray technologies are needed to replace inefficient conventional airblast 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/m3) and high (0.13 L/m3) 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 consumptions, chemical cost savings, controls of fungal diseases and Japanese beetles, and yields among the three treatments and non-treated 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 non-treated 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 non-treated control plots for the majority of sampling periods each year and furthermore, intelligent-high rate treatments suppressed Japanese beetles just as well as conventional airblast treatments. The multi-year field tests demonstrated that 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.