By Donna Fleury
Key cropping strategies
There are a couple of key cropping strategies that can have a major impact on weed seed predators.
Avoid indiscriminate use of insecticides: "[It's] discouraged, as applications can also kill beneficial insects, as can some herbicides,” says Chris Willenborg, assistant professor in the department of plant science at the University of Saskatchewan. “Trying to avoid insecticide applications where they are not necessary or critical can help protect carabid populations.
Cover crops: very important for seed predators, which is often lacking in the fall across Western Canada. Cover crops become extremely important not just for building soil, but also for maintaining cover for seed predators because these insects are easily consumed by birds without adequate cover for concealment. Interseeding and relay-cropping practices help maintain that cover, as can perennial crops. In Europe and the U.S., field margins and buffer strips can be planted and maintained, which provide refuge for the carabid beetles to return to after dispersing to forage for weed seeds.”
Reducing tillage: This is something that has already been done well in Western Canada. Strip tillage or ridge tillage, another strategy that is becoming more common in the U.S., creates a ridge or strip between crop rows, leaving weed seed predator habitat in that space. Shallow tillage is also less disruptive than deep tillage, which mixes both predators and their larvae deep into the soil.
Mowing weeds: Doing this in the fall is another practice that could help improve habitat conditions for carabids. Mowing weeds or delaying tillage gives seed predators time to consume seeds before they are buried or their habitat is disturbed.