Assessment of Non-Chemical White Grub Control in Turf through Mechanical and Injection Cultivation Methods

Abstract

We sought to determine if various turfgrass cultivation machinery was capable of reliably reducing populations of below-ground feeding white grubs in two different turfgrass systems (golf course and athletic field turf). In the first experiment, grub mortality was observed with all equipment types (hollow-tine, solid, vibratory-tine, air and solid injection equipment). However, given the low densities (~ 5 larvae per ft.2) and patchiness of the natural grub populations, only single- and double-passes of hollow-tine equipment were able to reduce populations when compared to untreated controls. In the second study, hollow- and solid, vibratory-tine treatments were capable of reducing grub populations below commonly accepted damage thresholds ( < 10 larvae per sq. ft.), though hollow-tine treatments provided the only statistically significant reductions. In both study locations, traditional hollow-tine cultivation provided superior control to solid, vibratory-tine cultivation in both grub mortality and surface disruption. These studies indicate that performing routine cultivation can provide secondary benefits in reducing grub populations, and when performed intensively, may serve as a stand-alone pest management tactic for turfgrass systems where chemical insecticides are not an option.