VEGREVILLE, Alta. – Farmers are being encouraged to walk their fields and count the weeds before automatically grabbing a pail of herbicide each spring.
Herbicide resistance in weeds is growing at an alarming rate and researchers are looking at alternatives to herbicides to slow the building resistance, said a senior research scientist at the Alberta Research Council.
“We’re seeing a development of weed resistance to herbicides on the Canadian Prairies in the last eight years,” said John O’Donovan. “It can have serious consequences for farmers.”
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One alternative is to scout the field to get a good idea of the number of weeds in each field. If the weed count is low or the stage of weed is not as advanced as the crop, farmers are encouraged to skip spraying to prevent herbicide resistance.
“Farmers should scout fields more often to see if they need herbicides every year,” he said.
It’s estimated weeds cause about $115 million in losses each year in Alberta. In addition, Alberta farmers spend about $250 million on herbicides each year. Nationally, the number is close to $1 billion.
Scientists are working on a computer model for farmers to judge if missing a year of chemicals will outweigh the problems of developing more weed seeds the following year.
“There is a trade off of getting more weed seeds with a decrease in herbicide resistance in weeds.”
They are also looking at a variety of practices like seed placement, fertilizer placement, row spacings or crop rotation to help reduce weeds.
O’Donovan points to green foxtail as a good example of a weed that can be reduced by alternative practices. The shallow-rooted weed can’t reach deep for fertilizer. By deep banding fertilizer out of the weed’s reach, the crop can easily outgrow the weed.
“Where it can’t access nitrogen or sunlight it tends to die out.”
