Crop pest and disease watch for 2015

Some of the usual suspects could be back this year, 
especially if you are pushing your rotations

Reading Time: 6 minutes

The new growing season is underway, with a combination of old and new challenges and opportunities. Alberta Farmer reporter Alexis Kienlen asked some experts about things that producers should look out for this growing season. Here’s what they had to say:

Plant diseases

It’s difficult for plant pathologists to predict the possibility of diseases, said Kelly Turkington, a plant pathologist with the Agriculture and Agri-Food Canada research centre in Lacombe.

Kelly Turkington
Kelly Turkington photo: Supplied

“With diseases, you can get a feel for what has developed the previous year or two years previous depending on your rotation, but by and large, it’s really influenced by what happens in the growing season, especially in terms of weather conditions,” said Turkington.

It’s much easier to predict potential insect problems, as experts can look at populations and egg counts.

But if plant diseases have been a problem in the past, they will likely continue to be an issue in the future, especially in tighter rotations.

Stripe rust is a disease to watch out for this year, especially in central Alberta.

“There may be some issues developing earlier than normal in winter wheat,” Turkington said. Stripe rust usually develops in early to mid-June in winter wheat, and in June to July or even later in spring wheat.

“In the broad sense, in cereals, I would look at what happened last year, especially if you’re going back into the same field with the same cereal or two years previous if you’re running the typical canola/cereal rotation,” said Turkington.

Alternating wheat/barley with canola is a rotation, but it’s not a particularly good rotation because the residue from two years prior remains in the field, contributing inoculum for an epidemic.

If you’re out scouting for weeds in lay May or early June, you may observe symptoms of tan spot and septoria in wheat or net blotch and scald in barley.

“You can use that as an indication that you’ve got a risk developing and you may want to come back in later to protect the upper canopy leaves,” said Turkington.

Fusarium head blight is another disease that used to be found mainly in southern Alberta, but that is starting to change.

“There’s certainly areas in central Alberta that are starting to see an increasing detection of fusarium graminearum in grain or seed samples, which is an indication that the pathogen is starting to build up on infested residues, which are the main source of disease,” he said.

This is mainly due to the tighter rotation.

To reduce disease pressure, it’s a good idea to have at least two years between cereal crops, and three years or four years between canola crops, to reduce the risk of blackleg.

Clubroot watch

Clubroot is still an issue, so farmers should scout for patches with poorer growth, or where the plants are dying, said Stephen Strelkov, plant pathologist and professor at the University of Alberta. Patches with poor yield or improper senescense are also suspect. Sclerotinia can also be the culprit, so if producers want to make sure they’re dealing with clubroot, they should pull out the roots to check for galls and root malformations.

Steve Strelkov
Steve Strelkov photo: Supplied

“Even if you’re growing a clubroot-resistant variety of canola, you should still look, given that there are some new strains that can overcome the resistance,” said Strelkov.

He encouraged producers who are growing resistant varieties to watch for the disease, so experts can be made aware of the extent of resistance breakdown and new strains of the pathogen.

“Try to mitigate the spread by preventing unnecessary movement of infested soil, and working infected fields last,” he said. If possible, producers should also sanitize their equipment and vehicles or at least try to remove the biggest chunks of soil, to minimize the spread of the inoculum on machinery.

Anyone who finds clubroot in their field can phone their county fieldman, their local agronomist, an agronomist at the Canola Council or Alberta Agriculture and Rural Development.

Clubroot is most commonly found at the entrance of fields, but it’s also worth it to keep an eye on low-lying, moist areas.

Producers who live in areas where clubroot has already been found should be on the lookout, since there’s a bigger chance that clubroot could move onto their particular field.

Hot spots in the province include the Edmonton area, and central Alberta.

“It’s not very well established in southern Alberta, but there is a significant amount of cases around Red Deer,” he said.

The insect situation

The grasshopper situation this year could be a little confusing.

Scott Meers
Scott Meers photo: Supplied

“Basically, we’re seeing lower numbers this year, but we’re seeing an increase in southern Alberta, where the numbers have been extremely low for a long time,” said Scott Meers, insect management specialist with Alberta Agriculture and Rural Development.

There’s a higher risk for grasshoppers in southern Alberta than in previous years, but producers don’t need to sound alarm bells yet.

The forecast for wheat midge is showing that the main risk this year will be in central Alberta, east of Edmonton and all the way to the Saskatchewan border. The other hot spot could be irrigated wheat around Bow Island in southern Alberta.

Producers can expect fewer troubles with bertha army worm.

“If we have trouble, it will be west of Highway 2 in central Alberta,” said Meers.

The threat of wheat stem sawfly is quite low as well, as there have been low numbers in the surveys the past few years.

Cabbage seed pod weevil and pea leaf weevil could be problematic in southern Alberta.

“If you’re in southern Alberta, you’ll be wanting to scout for cabbage seed pod weevil specifically,” said Meers.

A drier, warmer start to the season is favourable for lygus bugs, so producers should be on the lookout. Pests that can impact the emergence of crops include flea beetles and cutworms.

“We don’t think flea beetles will be extreme, but we’ve already had some reports of cutworm activity in southern Alberta, so that’s something we need to be watching for again,” said Meers, who tweets as @ABBugCounter.

“There’s always something that surprises us, so keep your ear to the ground, check our website and follow us on Twitter,” he said.

Some general agronomy tips

Agronomist Matt Gosling and his team did a lot of soil testing last year, and thinks the current moisture situation is fantastic.

Matt Gosling
Matt Gosling photo: Supplied

“The last few weeks of warm, windy weather has dried off the surface and has presented us with some good growing conditions. I think we’ve got a good situation here to have a really effective pre-seed burn-off season,” said Gosling, owner of Premium Ag out of Strathmore.

The past few years, Gosling has seen problems with pea leaf weevils in certain areas.

“The one thing that has been a little more frequent, but completely random, is the cutworm situation on canola,” he said.

It’s difficult to scout for cutworms, so Gosling encourages growers to look for the bugs out on higher, drier fields with a south-sloped exposure.

“If you see any activity, you’ll have to do a better job and get out there more frequently,” he said.

Gosling said that he’s heard a lot of talk during the conference circuit about spreading fertilizer, mainly straight nitrogen, in front of planters, before seeding.

“This is something that we’ve been doing for over eight seasons,” he said. “If it’s done properly, it’s quite effective.”

Gosling takes a lot of the product out of the seed drill and puts it in front of the seeding operation. Nitrogen stabilizing products that cause urea to stay for about 14 days, also seem to be getting a warmer reception.

Shallow-banded urea has just as much loss potential as surface-spread urea does, said Gosling.

“Putting a stabilizer on urea that is going to be spread is a really economical course of insurance,” he said.

“There’s lots of hype in the industry about that, so we’re going to be watching what we’re doing and documenting and measuring it,” he said. Gosling said his team will also be doing various trials with urea, ESN and other products to measure losses.

Some of the articles have indicated that putting Agrotain on urea that is going through a drill might also be a good idea, said Gosling.

About the author

Reporter

Alexis Kienlen

Alexis Kienlen lives in Edmonton and has been writing for Alberta Farmer since 2008. Originally from Saskatoon, Alexis is also the author of two collections of poetry, a biography, and a novel called "Mad Cow."

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