Late blight strikes Carberry area potato field

The latest Manitoba Potato News is reporting a confirmed find of late blight in a potato field in the Carberry area in the R.M. of North Cypress Aug. 17. The affected parts of the field have been tilled under and Curzate and a contact fungicide have been applied to the rest of the field and surrounding fields. A sample of the disease has been collected and will be sent for strain identification, the report by provincial plant pathologist Vikram Bisht says.

The report said the late blight risk model rates the risk of late blight development from medium to high at various sites. Bisht recommends producers tighten the frequency of late blight fungicide applications now that inoculum has been found in the areas. “It may be prudent to use systemic (translaminar) fungicides along with contact fungicides in high risk areas.”  However, the forecasted continuation of hot dry weather should limit disease progress and spread.

Producers should continue to monitor. “It is important to scout in wind-protected areas, like fields in  valleys and close to tree-line, where the foliage tends to remain wet longer after rains, irrigation or overnight dew,” Bisht said.

 

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Under-developed seeds germinating in canola pod

We are seeing instances of undeveloped “green” seeds that are germinating in the pod and in some cases shooting a root down the length of the pod. The plants are not affected by any disease, and have good soil conditions.

Answer

This has been seen in different regions of the province recently. With the hot and dry weather during ripening, we would normally assume seed sprouting while still on the plant should not occur. However, under very dry conditions “precocious seed sprouting” can occur.

In drought conditions, a hormone imbalance can occur in the seeds and prevent the hormones that stop sprouting to function properly, letting seeds sprout before the crop has reached physiological maturity. This was seen in 2010 during similar dry conditions in Alberta’s Peace River region. Unfortunately, nothing can be done to prevent this.

The CropChatter Team

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Canola red pods, pepper seed inside

We are finding quite a few canola plants with healthy developed pods that appear to be sun-bleached red. However, the seeds are completely red, not just the tops or “exposed” areas of the pod to the direct sun.

When opening up the pods, the seeds have stopped developing, and are “pepper,” so to speak, and are yellow and dark brown. The plants seem to be well developed, with no visible diseases affecting them, root to tip. Any ideas?

Answer

This sounds like a case of “sunscald” in the canola. This has been seen in several fields since mid-July in Manitoba. It is most likely to occur when canola is ripening during periods of prolonged heat and strong sunlight. The red or purple colour is a stress response caused by high levels of anthocyanin pigment and a lack of chlorophyll in the naturally maturing tissue. It is not a recorded cause of yield loss. Some varieties may be more susceptible than others and high levels in a field do not necessarily mean it is ripe and should be swathed.

The small yellow/brown seeds that look like pepper are probably attributed to the heat during ripening. Hot daytime temperatures and low rainfall during ripening cause the seeds to mature and dry down very quickly. Like the sunscald, there remains lots of seed pigment colour which tends to get locked in due to the environmental stress. Average individual seed weights on canola that ripened in hot/dry conditions also tends to be lower compared to canola that ripened under more moderate temperatures and more rain.

The CropChatter Team

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Is it okay to seed fall rye back into rye stubble?

Is it okay to seed fall rye back into rye stubble? I know the deadline to seed is Sept 15. Are there any pro/cons to seeding, say Aug. 15? How does rye do in loam soil? I’m thinking of doing a test plot on some land where I’ve never grown it before.

It is not recommended to follow fall rye with either fall rye or winter wheat because of problems with volunteer rye. Also, if ergot has been an issue, you should follow with a non-susceptible crop for at least a year. Fall rye is best seeded into stubble from a previous non-cereal crop that will allow trapping of snow to reduce winterkill risk.

Seeding fall rye too early usually results in reduced yield and lower 1,000-kernel weight. On the other hand, seeding too late can result in reduced yields, delayed heading, later maturity and lower bushel weight. Fall rye should normally have two to four leaves and up to one tiller before freeze-up, which generally means optimum seeding is in late August-early September. Insurance seeding deadlines for fall rye are Aug. 15 to Sept. 20 (full coverage), with an extended seeding period to Sept. 25 (20 per cent reduced coverage). For more information, contact your MASC agent.

Fall rye is adapted to a wide range of soil types and conditions. It’s a good choice for light, sandy, erosion-prone land, but will respond to better soil types and fertility.

The CropChatter Team

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