Photo Courtesy of the Government of Saskatchewan's Website

Ascochyta blight is a problem in field pea every single year.

Robyne Bowness, pulse crop and extension agronomist with Alberta Agriculture says you should be out looking in your crops for signs of ascochyta.

"You will notice a brown to purplish colour starting at the base of the plant. It will be kind of circular or oval in shape and you will see it on the stems as well as the leaves," she explains.  

Bowness says there are a number of strategies to manage this disease but if you're using a fungicide the timing is critical.

"You should go into the crop and have a good idea what the level of the disease is and then monitor it every week. If you are starting to see the disease move upward from the bottom of the crop then you may want to consider spraying some fungicide on it," she says. "Whether to spray a fungicide or not is a judgment call. You have to take into consideration how much of the disease is there and what the weather conditions are going to be like."

She says if the weather conditions are wet, the disease moves faster and if the crop has a really thick canopy the disease will also move faster.

"It really comes down to whether the cost of a fungicide application is going to be more than the yield loss you may expect," she says. "You have to expect a yield loss of more than 10% for the fungicide to be worth the cost of application."

However, Bowness says you can't do anything to correct the damage that has already been done.

"Spraying a fungicide would be more of a protector, so if you see the disease coming you would want to spray so you could protect the green tissue that is remaining so it doesn't spread further."