Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Master of Science in Horticulture (MS)

Degree Level

Graduate

Department

Horticulture

Advisor/Mentor

Bertucci, Matthew

Committee Member

Popp, Michael

Second Committee Member

Besancon, Thierry

Keywords

autonomous weeder; unmanned ground vehicle

Abstract

Vegetable production requires intensive weed management. Conventional producers rely on herbicide applications to manage weeds effectively at low costs; however, growers are under pressure to minimize chemical use due to environmental concerns and increased incidences of herbicide resistance. Non-conventional systems, including organic and sustainably focused small-scale production, rely primarily on cultural practices and physical weed control methods, which are labor-intensive and costly due to limited labor availability and rising wages. These concerns have prompted the development of autonomous weeding devices, such as unmanned ground vehicles (UGVs) equipped with navigation sensors and implements to provide repeated, high-precision weed control. Compact devices that mechanically cultivate on predetermined GPS maps, such as the Naïo Oz UGV, may be a solution to reduce chemical and labor inputs for small-scale vegetable producers. However, there is a lack of research on the efficacy and economic viability of the UGV. This research assessed the weeding performance of the Naïo Oz UGV in sweet corn (Zea mays L.) and edamame (Glycine max L. Merr.), as a stand-alone strategy or as a supplement to select pre- and post-emergence herbicides. Weekly UGV cultivations did not effectively manage weeds in sweet corn, where high weed densities and environmental conditions inhibited performance, thereby producing 28%, 58%, and 65% of the weed-free yields in three locations in 2024. Relative to the weed free check, yields increased to 56%, 67%, and 79% when UGV cultivations were initiated 30 days after a preemergence herbicide, but this integrated strategy underperformed compared to all-season herbicide-only treatments achieving 70%, 82%, and 97% of the weed-free yields. Weekly UGV cultivation in edamame resulted in >610 g m-2 of weed biomass at the end of the growing season, whereas all-season herbicide-only treatments, hand-weeding, and integrated strategies resulted in < 60 g m-2 weed biomass at two of three locations. Nonetheless, weekly UGV cultivations produced similar edamame yields in comparison to other weed management strategies at all three locations and thereby similar economic returns in comparison to other weed management strategies at two locations. Additionally, integrating UGV cultivations with hand-weeding resulted in 70% less hand-weeding times compared to hand-weeding only. Based on these findings, the Naïo Oz UGV may be an economically viable option in small-scale vegetable production, offering a potential solution to reduce herbicide use and provide labor-savings, especially when integrated with other weed management strategies.

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