Dryness, cool weather set back alfalfa seed crops

Alberta’s alfalfa seed crops are two to four weeks behind normal development for this time of year.

Dry conditions in spring, before irrigation was available, have combined with cooler than normal temperatures this season to delay progress, said Alfalfa Seed Commission research and extension manager Brad Alexander.

But that’s not the only pressure on the crop, he added.

“The bigger issue … is the bees. If we continue to have this cool temperature with cloud cover and such, the bees don’t want to go out and pollinate the alfalfa so we’re going to have low yields of seed.”

Average temperatures in the Brooks, Alta., region, where much of the alfalfa seed is contracted, are usually around 26 C for this time of year. However, this year temperatures have hovered in the mid to high teens in late June and early July.

Acreage of alfalfa seed crops, as well as price, is also down this year. There is plenty of supply, so seed companies did not offer new contracts this year, said Alexander.

“I suppose if there’s one kind of silver lining around it, it’s that we had some bumper crops the past few years and if we don’t have a bumper crop this year, then the seed price will go back up.”

Weevil damage is also evident in the Rosemary, Alta., area, where alfalfa weevils have proven to be resistant to synthetic pyrethroids, one of the few pesticide options available for the crop.

“They seemed like they weren’t going to come out, all the weevils. It just didn’t seem like they were going to be a problem this year, and then all of a sudden, one morning you wake up and there’s over 100 per sweep,” Alexander said.

Agriculture Canada researcher Hector Carcamo has undertaken a project to sample weevil-infested fields and those around them to develop a monitoring protocol. In the meantime, alfalfa seed growers have to rotate their chemicals as much as possible to avoid development of further chemical resistance.

That isn’t easy given that one of the few options, malathion, is ineffective unless applied at temperatures above 21 C.

Contact barb.glen@producer.com

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