Recently in disease management Category

I took over as editor of Grainews nearly a year ago. Just as I was getting into the swing of things, the endless seeding season of 2010 reared its ugly head and I could focus on little else. Of course, I live near Regina — not everyone faced such a dire growing season, but many did. Now, we've passed the half way point of winter (according to me) and the snow outside my door looks more like winter in the Red River Valley than "bone-dry Saskatchewan." (I was told last summer not to complain about the rain or it would stop for three years. Should I still be so careful? Maybe.) I'm hoping that my second year at the helm of this pub isn't nearly as exciting as the first. Really.

Difficult growing conditions here and abroad have done what they should for crop prices. Many farmers who missed out on production are taking some solace in price run ups of nearly every commodity (thank goodness). But wet weather leads to heavy disease pressure and low levels of quality seed stock. The farmer who fails to plan their crop selection early may find themselves short on their first choice or highest quality of seed.

While booking canola seed largely wrapped up in the late fall, many of you are still hammering out crop rotations or, to put it bluntly, returning to them.(I've said it before and I'll say it again, one in two is not a rotation.) The good news is many of the tried and true staples of western Canadian farming should be profitable this year at current pricing levels, the bad news is much of Manitoba and Saskatchewan are going to need perfect spring drying weather to get crops in on time.

Even timely seeding can't entirely make up for the dangers of seeding into wet conditions with (potentially) high levels of disease inoculum in the soil. It'd be prudent to pencil in a seed treatment, if you don't already, to this year's budget, I'd say.

Then there are those of you anticipating really wet conditions. In upcoming issues of Grainews, we'll be tackling the success rate of scratching in canola as well as highlighting cropping options that either don't mind wet feet, use a lot of water or will at least offer some ground cover and water use for 2011. For many, this cycle of wet weather is set to continue for a bit yet. Longer-term planning outside of your comfort zone, such as with winter wheat, forage and cover crops or big water users, may prove a wise move. 

Of course, I say all of this and plan all these articles in the hopes that most of you don't need to employ these tactics. But the reality is, you may.

Happy planning!

It's an unfortunate fact that diseases can mutate and evolve to overcome genetic resistance. What's more unfortunate is that tightening up canola rotations can speed that evolution. Recently, new strains of blackleg have been showing up in canola — strains that are unaffected by current genetic resistance. While plant breeders are hard at work developing new resistant varieties, the Canola Council of Canada is reminding farmers about several things they can do to combat the disease and preserve what genetic resistance we do have now.

Agronomists, plant pathologists and this editor will tell you that the first step in controlling blackleg is keeping canola to a one-in-four year rotation. But if everyone did that, we likely wouldn't be having this discussion, so let's move on to other steps you can take to manage blackleg, according to the Council's latest release on the topic.

1. Choose a variety with an MR or R rating for the disease. The tighter the rotation, the more important the R rating.
2. Rotate varieties. This works because different lines carry different sources of resistance, according to the Council's release.
3. Scout early for signs of the disease and again just prior to maturity. Cankers or lesions that form at the base of the plant are responsible for significant yield loss.
4. Control volunteers in the years in between canola crops. This includes any host crop, such as wild mustard. Volunteers act as host to the disease, setting back any advantage to rotating away from canola.
5. Use certified seed to ensure genetic uniformity
6. Fungicide acts as protectant only, and must be sprayed in anticipation of the disease, not after infection is wide-spread. According to the Canola Council, research at AAFC Melfort found fungicide use made the most difference on those varieties with a less than R rating.

In addition to all this, remember to keep growing conditions in mind. Warm and wet weather can speed along development of the disease. And because blackleg spreads by wind, it's important to scout the field margins between last year's and this year's canola field (if growing side by side). The Canola Council also says that burning stubble is not effective control — the thick base of stalks which carries so much inoculum rarely burn completely.