Spring showers have stalled insect development across the Prairies and promoted crop disease outbreaks in some regions.
Saskatchewan Agriculture insect specialist Scott Hartley said the grasshopper hatch that began two weeks ago has “pretty much died back.”
In fact, wet conditions have delayed almost all insect development.
The only bugs causing problems in Saskatchewan are flea beetles, which have migrated from the leaves to the stems of canola plants to avoid the cool conditions.
“That’s not a good place for them to be feeding,” said Hartley.
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Paul Laflamme, pest management specialist with Alberta Agriculture, said the high humidity will promote disease development in grasshoppers and other insects, which should control populations. But there is another important side effect of the rain.
“It allows the crops to outgrow the problem. The crops can actually grow faster than the grasshoppers can eat them.”
There is also a downside to the abundance of moisture.
“If it stays wet long enough, we’re going to start seeing some root diseases show up for sure,” said Laflamme.
Diseases like root rot and seedling blight could become a problem. If it stays moist, farmers can expect to deal with leaf diseases such as septoria, net blotch and ascochyta blight.
In Manitoba, where much of the province received twice the precipitation and half the heat units in May compared to a normal year, farmers are already dealing with those problems.
Wheat crops there are suffering from tan spot. The fungal disease is particularly acute in crops grown on or close to wheat stubble.
“It’s alarming to the point that people notice it from the road,” said Manitoba Agriculture plant pathologist David Kaminski.
Growers may consider applying fungicides when they apply herbicides. Kaminski said that’s just one control option that may or may not pay benefits.
“They (producers) think a fungicide application is a necessity. It’s not a necessity.”
Kaminski said research has shown fungicides can generate a three- to five-percent yield response in moderate- to high-pressure disease situations.
But most of a plant’s seed-plumping energy comes from its last two leaves, not the initial growth that may be suffering from tan spot.
Kaminski said there is also a fair amount of net blotch being reported in barley crops and Manitoba’s oat crops have a brown or reddish tinge caused by bacterial blight. Frequent rain showers have amplified symptoms of both diseases.
“That’s what really gets it going in a crop. You don’t need much inoculum to start and it looks very bad.”
Oat growers may think they’re dealing with barley yellow dwarf virus, but Kaminski said that virus never starts this early or looks as uniform as the blight.
Fungicides are ineffective when dealing with bacterial blight. The only cure is to wait for dry, sunny weather.
