White Grubs in Turfgrass

Turfgrass

Identifying Alternatives to Neonicotinoids and Chlorpyrifos for Controlling Insect Pests in New York’s Specialty Crops: Preventative and Curative Control of White Grubs in Turfgrass

Project Summary

Field experiments were launched in the summer of 2022 to explore potential alternatives to neonicotinoids for both preventative and curative control of root-feeding, white grubs, Japanese beetle and European chafer, in turfgrass. A total of 120 plots of common, lawn-type turfgrasses were infested with white grubs through two methods—confinement of 20 male and 20 female beetles and the direct addition of 3rd instar white grub larvae into soil. Once sufficient infestation levels were reached, plots were covered with mesh to maintain populations and mowing was avoided, to avoid disruption of the trial areas.

Conventional insecticides used to evaluate Japanese beetle included imidacloprid, the most common active ingredient in neonicotinoids used to control white grubs in turfgrass, and anthranilic diamides, chlorantraniliprole and tetraniliprole. Chlorantraniliprole is currently labeled for white grub management in New York. Tetraniliprole is not. The anthranilic diamides were assessed for both preventative and curative performance.

European chafer plots received of three treatments: water only, entomopathogenic nematode (EPN), Heterorhabditis bacteriophora at a supplier-recommended rate of 86 million per acre or at the Cornell-recommended rate of 1 billion per acre.

Trial areas were harvested and white grubs were enumerated on September 29, 2022 and October 25, 2022. Trial arenas are being removed and data analysis is currently in progress

Findings are preliminary and are not intended to replace current management plans or control methods. Additional research is being conducted to help inform long term recommendations and guidance.

Progress Report

In the summer of 2022, field experiments were initiated by Cornell AgriTech to evaluate alternatives to neonicotinoids for both preventative and curative control of root-feeding, white grubs in turfgrass. A total of 120, 4-foot by 2-foot experimental plots were established in common, lawn-type turfgrasses, comprised primarily of a mixture of tall fescue (Festuca arundinacea) and Kentucky bluegrass (Poa pratensis). In each plot, trial arenas were installed using 6-inch diameter PVC for the purpose of creating uniform but confined infestations of the economically important annual white grubs Japanese beetle (Popillia japonica) and European chafer (Rhizotrogus majalis). White grub infestations were achieved through one of two means. In the case of Japanese beetles, forty adult (20 male and 20 female) beetles were confined to arenas, with specific time allocated for mating and depositing of eggs below ground within the arena soil. In European chafer plots, 3th instar white grub larvae were infested directly into plot soil. Adult beetles were collected during the first two weeks of July using sweep netting and floral lures in and around untreated vineyards and farm edges (wild grape and Virginia creeper). Once collected, the beetles were maintained in a lab on a steady diet of apple slices. Sufficient numbers were achieved, plots were infested with beetles on July 15, 2022, and arenas were covered with mesh to confine the beetles. Mowing was suspended during the confinement period to avoid disturbance of the arenas.

people sitting on turfgrass working — Wickings lab members infesting turfgrass plots with Japanese beetle adults.

two people working together seated on grass — Wickings lab Summer Scholar Interns, Megan Jerke and Mackenzi Stezkowski, infesting turfgrass plots with Japanese beetle adults

Japanese beetle

Conventional insecticides evaluated against Japanese beetles included imidacloprid, the most common neonicotinoid active ingredient used in turfgrass for managing white grubs, as well as two anthranilic diamides--chlorantraniliprole, and tetraniliprole. Chlorantraniliprole is currently labeled for annual white grub management in New York, while tetraniliprole is not. Additionally, the performance of both anthranilic diamides was assessed when applied either preventatively in May or curatively in July. Chlorantraniliprole was applied at a rate of eight fluid ounces per acre, Tetraniliprole at a rate of 32 fluid ounces per acre, and imidacloprid at ten fluid ounces per acre.

European chafer

All plots were infested with 3rd instar larvae (six per arena) on October 11, 2022. On October 25, plots received one of three treatment applications: water only, the entomopathogenic nematode (EPN), Heterorhabditis bacteriophora at a supplier-recommended target rate of 86 million per acre, or the same at Cornell-recommended target rate of 1 billion per acre. All EPNs were applied in in room temperature water after a short (less than 30 minutes) period, and all product containers were agitated gently to prevent settling of the nematodes. The nematodes were applied using low pressure, soil drench nozzles in the equivalent of 30 gallons of water per 1000ft ². Applications were made using a CO2-powered boom sprayer. Following applications, all plots were hand watered for 20 seconds each to wash nematodes from foliage into the soil.

White Grub Arena Harvest

All arenas were harvested and annual white grubs were enumerated on September 29, 2022 (Japanese beetle) and October 25, 2022 (European chafer). Trial arenas are all being removed from the field and data analysis is currently in progress.

Preventative and Curative Control of White Grubs in Turfgrass