Development of novel and blended insecticide formulations for low risk management of wireworms in potatoes

Project Code : MUR06-310

Project Lead

Bob Vernon - Agriculture and Agri-Food Canada

Objective

To identify through field and laboratory trials a number of lower risk, effective insecticide candidates for wireworm management in potatoes

Summary of Results

Field efficacy trials were completed at sites in Agassiz, BC (R. Vernon, project leader), London ON (collaborator Jeff Tolman) and Charlottetown, PEI (collaborator Christine Noronha) to collectively evaluate various reduced-risk insecticides and application procedures for management of wireworms in potatoes. The main wireworm species of concern are Agriotes obscurus (BC), a complex of Melanotus spp. (ON), and A. sputator (PEI).

At all sites, Thimet 15G (the organophosphate phorate) was tested as a standard treatment. In common between Agassiz and London was the evaluation of two new Dupont insecticides, DPX E2Y45 (chlorantraniliprole) and HGW86 10SC applied as in-furrow sprays at planting. These new insecticides had absolutely no effect on wireworm damage at either site, nor did they have any effect on damage when applied as potato seed piece treatments in the Agassiz trial. In London, two additional insecticides, Dow Exp (an unknown formulation), and BAS 3201 240 SC (containing metaflumizone), applied as in-furrow sprays also did not provide any damage control, and these numbered compounds will not be tested further. Also at the London site, fipronil (Regent) applied as an in-furrow spray, and fipronil (ICON) applied to wheat seed and applied to potato furrows at planting as an attract and kill strategy (A&K), provided as good or better control than the standard Thimet 15G.

In common between the Agassiz and Charlottetown sites was the evaluation of Cruiser 5FS (thiamethoxam) at 4.2 and 9.0g a.i., and Poncho 600 (clothianidin) at 6.2 and 9.5g a.i./100kg potato seed. In Charlottetown, both Cruiser and Poncho potato seed treatments at both rates tested had significantly less damage than the untreated check plots, and significantly fewer damaged tubers than the Thimet 15G treatment. In Agassiz, the Poncho (6.2 and 9.5g a.i./100kg seed) and Cruiser (4.2g  a.i./100kg seed) treatments had numerically less damage than the untreated check plots, but not less damage than Thimet 15G. Only Cruiser (at 9.5g a.i./100kg seed) and Actara (at 4.2g a.i./100kg potato seed) both containing thiamethoxam, had significantly less damage than the check plots, and were similar in efficacy to Thimet 15G. In Charlottetown, contrary to a trial run in Kentville, NS in 2005, results with Cruiser 5FS and Poncho 600 appeared promising and these trials will be repeated in PEI and Agassiz in 2007.

Of particular interest in the Agassiz trial was that combinations of chlorpyrifos (Pyrinex 480EC) applied as an in-furrow spray, along with low rates of Actara or Poncho applied as potato seed piece treatments, provided significant wireworm and tuber flea beetle damage control as well as wireworm population control equivalent to Thimet 15G.

Laboratory studies using soil bioassays (developed in a previously funded project, MU03-ENT1) indicated that thiamethoxam applied to wheat seed is not repellent to A. obscurus and Limonius canus. The synthetic pyrethroid, tefluthrin was highly repellent to both A. obscurus and Limonius canus when presented on wheat seed.

Results of this work have been presented to growers and extension personnel across the country, including to the BC Wireworm Task Force in December 2006.

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