Powdery mildew may be a problem on dry pea crops again this year, especially in areas where seeding was delayed, said Penny Pearse, Saskatchewan Agriculture plant disease specialist.
Symptoms usually appear in fields near the end of July, so scouting should begin during the last two weeks of July to identify the disease early.
“Late seeding during or after the last week of May and slow crop development compounds the harmful effect of the disease because the pods and seeds are not developed before the infestation occurs,” Pearse said.
Read Also

Farming Smarter receives financial boost from Alberta government for potato research
Farming Smarter near Lethbridge got a boost to its research equipment, thanks to the Alberta government’s increase in funding for research associations.
“On crops with pods and seeds already developed, the disease may cause plants to look bad, but it will have very little economic impact.”
Symptoms include development of white, powdery spots on lower leaves and stems that can eventually spread to the entire plant.
Severely affected crops are covered in a white mat of powdery spores and may appear to have a bluish or silvery sheen. The underside of leaves turn yellow below the powdery infection.
“Early infections reduce the usable leaf area, stunt plant growth and affect the development of the pods and seeds. The disease can reduce yield, delay maturity and make it difficult to do a proper job of desiccating the crop.”
Warm, sunny and dry conditions during the day, with cool nights and heavy dew in the morning favour the disease.
Pearse said some new pea varieties have excellent resistance, but many varieties commonly grown in Saskatchewan are susceptible.
Kumulus DF is a registered fungicide for prevention. It does not cure leaves already diseased, so application must be made before infection, or at the first sign.
Headline EC fungicide is applied at the early flower stage or the onset of symptoms.
“If a fungicide application is necessary, spray-water volumes should be high to ensure proper coverage of all the crop foliage.
“Repeat applications may be required if weather conditions that favour the disease persist. Growers who have used Kumulus DF also recommend that sprayers be thoroughly flushed soon after application to prevent plugging.”