Response of Annual Bluegrass <i>(Poa annua)</i> , Bermudagrass, Creeping Bentgrass, and Smooth Crabgrass <i>(Digitaria ischaemum)</i> to Laser Intensity Levels and Patterns

Abstract Laser weed control is an emerging non-chemical technology made feasible by recent advances in artificial intelligence and automation. This research evaluated the response of four turf and weed species to varying levels and patterns of laser intensity to determine practical applications of laser weeding in turfgrass systems. Field experiments were conducted from July 2024 to March 2025 on research fairways in Blacksburg, VA, using a 10 W diode laser in spiral patterns with varying pattern-averaged energy densities (PAED). Two studies were implemented: one evaluated increasing energy intensity, and the other assessed combinations of line spacing, PAED, and number of passes in a factorial design. Line spacing significantly influenced weed control efficacy, with 4-mm spacing improving green cover reduction by up to 10% over denser patterns at the same PAED. Bermudagrass [ Cynodon dactylon (L.) Pers.] recovered fully within 24 days post-treatment, while creeping bentgrass ( Agrostis stolonifera L.) showed prolonged injury at higher intensities and wider spacings. These results demonstrate that laser weeding is feasible in turfgrass systems, especially with optimized energy and pattern configurations, and highlight the need for pattern customization to balance weed control with turfgrass safety.