Submitted by: Jeanette Gaultier, MAFRI Pesticides – Minor Use & Regulatory Specialist
You’ve adjusted your sprayer to account for the technical factors of drift reduction (nozzle selection, boom height, etc.) but many aspects of pesticide drift rely on applicator judgement. Consider the following before/during application:
Neighbouring crops: Don’t assume your neighbour’s canola, soybean or corn is herbicide tolerant. Drift is often allowed to occur to neighbouring crops based on the wrongful assumption of a particular herbicide tolerance package. Also, while drift should be avoided on all crops, remember that certain crops, such as flax, potato, sunflower and beans (to name a few), are especially susceptible to injury by certain herbicides.
Sensitive areas: Herbicide injury to shelterbelts accounted for ~15% of 2012 drift incidents. Know your buffer zones; product doesn’t have to go far to injure shelterbelts that are right next to fields. Returning to spray field portions next to sensitive areas after a shift in wind direction is an unpopular recommendation but one that could save you grief down the road.
Pesticide chemistry: Remember that ‘low volatile’ doesn’t mean ‘no’ volatile. Many low volatile (LV) Group 4 herbicide formulations still have relatively high vapour pressures. Use an amine formulation if it’s very hot or your field is next to a particularly sensitive crop (e.g. potatoes). Also keep in mind that many herbicide chemistries are effective at low doses (e.g. Groups 2, 14, 27). If it only takes a little to kill a weed, it only takes a little to result in drift injury.
Insecticides and fungicides drift too: MAFRI deals with a few insecticide/fungicide drift incidents a year. Most often it’s a case of insecticide drift during a temperature inversion causing product to ‘hang’ in nearby farmyards. While this doesn’t happen often, it should be avoided at all cost since pesticide exposure to humans and livestock can have serious consequences.
Check out SPRAYcast Manitoba (www.weatherinnovations.com/mb/) to generate a 3 day forecast of optimal application times.
Always refer to the product label.