Insect control products are re-evaluated by the Pest Management Regulatory Agency (PMRA) to ensure products continue to meet health and safety standards and environmental standards. There are cyclical reviews, which occur 15 years after initial registration and special reviews, which can be triggered by significant concerns both in Canada and in other Organization for Economic Co-operation and Development (OECD) countries.
In September 2017, PMRA put lambda-cyhalothrin, the active ingredient in Silencer 120EC, Matador 120 EC and Labamba and one active in Voliam Express, under review over 90-day consultation period. These products are used to control flea beetles, grasshoppers and cutworms, among other pests. It was proposed from this review that lambda-cyhalothrin be removed for use on feed and some food commodities in April 2021. The evaluation found that livestock feed use was unacceptable resulting in ADAMA and Syngenta putting a hold on products containing lambda-cyhalothrin so that they can update labels.
Stripped flea beetles feeding underneath a canola plant.
There are still many other products that a producer can use to control insect pests in several crops in the upcoming growing season.
Early-season insects that might cause issues are cutworms and flea beetles. Buteo Start, Prosper Evergol, cyantraniliprole (Fortenza or Lumiderm), Helix, and sulfoxaflor, all effectively control flea beetles and cutworms and are available in multiple products and co-packs as seed treatments for canola. The use of these products can’t guarantee damage won’t occur but will often help mitigate the pressure. These products work systemically and require the insect to feed on the plant to die. Seed treatments can work up to three to four weeks in aiding to control flea beetles; however, there are cases where the insect pressure is too high, and a foliar application of an insecticide is needed.
Foliar applied products that are registered on oilseed crops include other group 3 insecticides (synthetic pyrethroids) with the active ingredients deltamethrin, permethrin and cypermethrin. Group 1A insecticides are also available (malathion) as a regroup 1B (carbamates – Sevin). Permethrin (Pounce 384 EC) a group 3A contact insecticide will also demonstrate good control for flea beetles and cutworms up to the five-leaf stage in canola. Strong insect pressure may require more than one application. These products can be effective at controlling flea beetles and cutworms. Malathion is a non-systemic, contact organophosphate, is generally non-phytotoxic and effective in controlling flea beetles and grasshoppers. A more environmentally friendly control for grasshoppers is Nolo Bait, which uses wheat meal and spores of protozoan (Nosema locustae). The grasshoppers consume these spores that infect the fat bodies of a grasshopper, making it lethargic and reducing its feeding and reproductive activity. Dimethoate, a group 1B insecticide, can move systemically within the plant and kill on contact, making it effective for grasshopper control.
It is important to note that most insecticides are non-selective and do kill beneficial insects. It is essential when applying an insecticide that the pest is above the threshold before application. The threshold for flea beetles is when the plant has at least 25 per cent defoliation in several areas of the field and flea beetles are present and active. A cutworm's thresholds vary by crop but typically four to five larvae per square meter. The grasshopper threshold is generally 10 to 12/m2. Before application a grower should always know what the pre-harvest intervals are for each product they are applying.
For more information on registered insecticides and their uses for the upcoming 2023 growing season, contact your local agronomist or your local crops extension specialist.
You can listen to Glenda-Lee's conversation with Erica Yaskowich a crops extension specialist on the lambda-cyhalothrin issue by clicking the link below.