By Brandy Harrison
GUELPH — Farmers may want to turn the soil to hunt for unwanted bugs as early as this fall to ensure they can keep planting neonicotinoid-treated seed.
As of July 1, new regulations require farmers to have a pest assessment report to plant more than 50 per cent of their acreage to neonic-treated corn or soybean seed next fall or buy treated seed at all starting in 2017. Since soil assessments are self-reporting in 2016 and in two out of every three years, as it stands, there is no way to prevent inflating the numbers.
Here is a rundown of the two types of inspections.
Soil inspection pest assessment
Farmers have the best odds of finding wireworms or grubs in early September to late October when soil temperatures are typically moderate to cool and in the spring before or shortly after planting when soil temperatures are between 10 and 25 C.
But farmers should hedge their bets by hitting the fields in both seasons, says Tracey Baute, an OMAFRA field crop entomologist.
“Don’t rely on only fall scouting. One season can change quickly and limit your ability to do what you need to do.”
While growers can complete their own soil inspection this fall, they must have integrated pest management training or hire a professional pest advisor for assessments completed after Aug. 31, 2016.
Starting on Aug. 31, 2017, a professional pest advisor must conduct or supervise the soil inspection at least once every three years. Phased in over three years, most counties west of Toronto are scheduled for the first two years, with the exception of Brant, Chatham-Kent, Durham, Essex, Perth, and Simcoe counties in 2018.
Crop inspection pest assessment
Completed by a professional pest advisor on an untreated area of the field, the assessment compares five areas with failed emergence and damaged or poor vigour plants to five areas without stand loss.
If thresholds are met — 15 per cent stand loss in corn and 30 per cent stand loss in soybeans caused by wireworms, grubs, seedcorn maggot, corn rootworm, or bean leaf beetle — neonic-treated seeds can be planted on the entire field that includes the assessed plot.
For more on scouting timing and techniques, how to identify grubs and wireworms, and alternative insecticides visit www.ontario.ca/bx1n or read the early-season guide to field crop pests at www.gfo.ca/pestguide.aspx.
How to scout for soil pests
Baiting for wireworms
Establish bait stations in higher-risk areas, such as sandy or silty soils, south-facing field edges, or areas with grass weeds. Fields at higher risk include newly-broken sod and sandy and silty soil with frequent grass crop rotations, pasture, canola, or tuber-vegetable crops like potatoes.
Inspect a minimum of five locations at least 10 metres apart for each 100-acre or less plot. Consider extra bait traps to offset the risk of predators digging up bait.
At each location, bury bait in a hole approximately 15 centimetres square. Test different bait combinations, such as one cup of all-purpose flour or freshly-chopped potatoes or one cup equal parts untreated corn, wheat, and beans soaked overnight.
Mound soil over the bait to prevent standing water and place a flag and sketch a map to mark its location. If soil is cool, cover bait with a plastic bag to speed up fermentation.
After seven to 10 days, dig up traps and if an average of one wireworm is found over five locations, neonics can be planted on that 100-acre plot only.
Digging for grubs and wireworms
Target high-risk areas such as sandy knolls or near tree lines and patchy weeds on fields with grass crop rotations, following soybeans, or adjacent to pastures, sod farms, parkland, and golf courses. If the crop is already planted, look for wilting plants or gaps in the stand and dig up the next surviving plant.
At five locations at least 10 metres apart for each 100-acre or less plot, dig a hole about seven to 10 centimetres deep, sifting through the soil to break up clumps. Thresholds for buying neonic-treated seeds are set at an average of two grubs or one wireworm over five locations.
