RED DEER, Alta. – In the ongoing battle of farmer versus disease and weeds, the bad guys are winning, say Agriculture Canada scientists.
“We’re looking at an increased risk of disease,” said Kelly Turkington at a recent workshop here.
Part of the problem is due to modern practices where plants are bred for specific production qualities that don’t always include disease resistance.
The problem is similar to weeds that show resistance to common herbicides.
Modern crops are bred for uniformity and have a narrow genetic base. And fewer varieties are grown, which also leads to the spread of disease.
Read Also
VIDEO: British company Antler Bio brings epigenetics to dairy farms
British company Antler Bio is bringing epigenetics to dairy farms using blood tests help tie how management is meeting the genetic potential of the animals.
For example, researchers are finding scald resistance is weaker in some barley varieties like CDC Dawn and CDC Guardian.
“Unfortunately what’s happening in Alberta and western Saskatchewan, we’re seeing the scald resistance in a number of varieties break down,” Turkington said.
“We’re also seeing some indication that something similar is occurring with net blotch.”
There are tools to fight disease that go beyond using an arsenal of chemicals. These include improved fertility, direct seeding, better seed quality, field scouting and paying vigorous attention to crop rotation.
Rotating crops means more than planting a different cereal on the same field, but should also include switching around varieties.
Harrington barley is susceptible to a lot of diseases. Growing the same variety of barley on barley is huge risk factor. Growing it in the same spot is even worse. Turkington suggested mixing barley with triticale or oats to break a disease cycle.
A farmer can also rotate a disease out of a field.
In 1993 Turkington saw a canola field that was full of virulent blackleg. By not planting canola there until 1997, the disease disappeared.
Weeds resistant to herbicides are winning in Western Canada.
Rotation and trying different crops can help control some of these weeds.
Weeds are genetically diverse and can adapt to almost any new situation, said Neil Harker of Agriculture Canada.
“No matter what we do, they don’t seem to go away,” said Harker.
Broad resistance to several types of herbicides is reported in wild oats and green foxtail.
A chickweed count in a 80-kilometre radius around Red Deer, Alta., was stopped when researchers found there were too many sites of resistant chickweed to count.
Herbicide resistance is one reason weeds are on top, but other agronomic practices may encourage the weeds to survive.
Modern crops are selected from a narrow quality zone whereas weeds are selected by numerous random forces.
The soil is full of weed seeds that can lie waiting for the next best opportunity to strike.
“What comes up is only a fraction of the seeds that are down there,” Harker said.
He suggested more crop rotations and higher-than-average seeding rates to outcompete the weeds.
Another method is to turn barley into silage early in the year to break the weed cycle. If it is left too late in the season, the wild oats can still produce seeds.
