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Pests to watch for in 2013

Southeastern Alberta farmers have the unfortunate privilege of being at the crossroads of insect issues lately, says Scott Meers, insect management specialist with Alberta Agriculture and Rural Development. “It seems to be the area where virtually anything can happen, unfortunately.”

Farmers in the Medicine Hat area will need to watch for a litany of pests, including pea leaf weevils, cabbage seedpod weevils and even wheat midge. Wheat stem sawfly and grass- hoppers are sometimes a prob- lem in the area as well.

Wheat midge have also made themselves at home in the Peace region, particularly around Manning and in the Municipal District of Big Lakes. Though numbers are still low, Meers is concerned because they haven’t found a parasitoid to naturally check populations.

“It’ll take a few more years for them to build up. But if we get no parasitism up there, they could build up into quite high levels, which has been the experience in other parts of the world.”

Farmers in the MD of Willow Creek will need to look out for wheat midge as well.

Canola growers in southern Alberta and the southern part of central Alberta will need to check for cabbage seedpod weevils as the crop starts to flower. Pea leaf weevils may be a problem for farmers south of Highway 1, as well as those in Wheatland and Newell Counties.

Bertha armyworms are a potential scourge for central Alberta this year. Last year’s most severe infestation was south of Lloydminster. The ber- tha armyworm swath stretched from the Lloydminster area to the Lamont area, and there was also a hotspot in Vulcan County.

Flea beetles were scattered around central Alberta and the Peace last fall. “If producers were noticing flea beetles while they

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were swathing or on late volun- teer canola in their yards and stuff like that in the fall, that’s next year’s damaging popula- tion,” says Meers.

But it’s not all bad news. Meers says grasshopper and wheat stem sawfly numbers are down substantially from previous years. “There may be hotspots, but really not the big massive outbreaks that we’ve seen in the past of either of those for 2013.”

Farmers can access insect fore- casts at www.agriculture.alberta. ca/bugs-pest. Farmers can also submit their own counts for insects such as cabbage seedpod weevils and cutworms through the site. Scott Meers is also on Twitter (@ABbugcounter). 

Bertha armyworm in Saskatchewan

Bertha armyworms are likely to be a problem in several parts of Saskatchewan this year, says Scott Hartley, pest specialist with Saskatchewan Agriculture.

“Certainly some (farmers) are right in the middle of the current outbreak, so it’s likely that some will still be very high this year in populations. And some areas will be starting on a decline as the outbreak ends.”

Hartley says they had many reports of diseased bertha army- worms, which is usually a sign of declining populations.

Alfalfa weevil populations were also high throughout most of Saskatchewan last year, and alfal- fa growers should watch for them and be prepared to control them.

Much like Alberta, flea bee- tles were a problem in parts of the province last year. Whether or not they’ll be a problem in 2013 will depend on spring con- ditions. “Cool, wet conditions don’t favour the flea beetles,” Hartley says.

Pulse growers in southwestern Saskatchewan should look out for pea leaf weevils and consider seed treatments for peas. Pea leaf weevils are also a concern in faba beans. Cabbage seedpod weevils may also be a problem for canola growers in southwestern and south-central Saskatchewan.

Wheat midge risk is moderate to high for central Saskatchewan. Moisture in southwestern Saskatchewan has upped the wheat midge risk in that area as well.

Hartley says swede midge isn’t widespread, but the insects reached economic levels in the Tisdale area last year. “It’s one we just want to keep watching because the potential is there for it to be a big problem.”

Saskatchewan farmers can visit www.agriculture.gov.sk.ca and search the site for “insects.” The first search result will bring farmers to the crop insect page, which includes insect forecast maps. Hartley says they will also distribute information through the Ag Knowledge Centre bulletins and Crop Production News. If insect problems arise, the ministry will also contact local radio stations. 

Manitoba pest forecast

Dr. John Gavloski is an entomol- ogist with Manitoba Agriculture. Gavloski says Manitoba farm- ers had localized problems with bertha armyworm last year. A Carberry trap yielded 1,500 ber- thas in the last week of June. Areas around Inglis and Baldur

were at moderate risk. Farmers in western Manitoba sprayed for ber- tha in late July and early August. Disease may knock down the populations this year, as diseased worms were seen last growing sea- son in the northwest, southwest, and Interlake regions.

Alfalfa weevil numbers were also higher than normal last year so alfalfa growers should monitor the first cut, along with the early regrowth of the second cut, Gavloski says.

Cutworms were also a problem in parts of Manitoba in 2012. The cutworm species that caused prob

lems last year overwinter, so farmers in affected areas should keep an eye out for cutworms in May and June.

Grasshopper populations were sparse in most of Manitoba last year. But areas near Clearwater and Plum Coulee had moderate risk levels, and one area south of Crystal City had a higher count. If the weather becomes warm and dry, hopper populations could build in some areas.

Flea beetle numbers were high in some canola crops even though most canola seed had been treated with an insecticide.

Manitobans can access the insect forecasts under the e-newsletters and e-bulletins link on the home page of www.gov.mb.ca/agriculture. Farmers can also subscribe to insect updates from the website. 

Aster leafhoppers

Both Hartley and Meers say that farmers have been voicing concerns about aster leafhoppers, 

which spread aster yellows. Aster leafhoppers were common across Manitoba as well.

Unfortunately aster leafhopper outbreaks aren’t easily controlled or forecasted right now. The leafhop- pers don’t always spread aster yellows, either. Hartley says the Prairie Pest Monitoring Network is consid- ering monitoring wind currents to forecast leafhopper infestations.

“So maybe we can get an indica- tion of something moving in, or potentially moving in. But still, there’s no economic threshold for it. There’s too big a chance of reinvasion from neighbouring fields or more blow-ins from the south. Trying to control the aster leaf- hopper is not really economically viable,” says Hartley. 

About the author

Field Editor

Lisa Guenther

Lisa Guenther is field editor for Grainews based at Livelong, Sask. You can follow her on Twitter @LtoG.

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