LETHBRIDGE, Alta. – A survey conducted in Alberta has highlighted insect pests that may pose problems this year.
Scott Meers of Brooks, a provincial insect specialist with Alberta Agriculture, said the annual survey includes seven insects of concern.
Bertha armyworms are at the low end of the problem scale, Meers told the Irrigated Crop Production Update 2010 conference this week.
But despite the outlook, he feels an annual check is still important. He suggested farmer co-operators continue to work with him.
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“We should get a warning of an increase a year ahead of a major outbreak.”
The survey map is updated daily with data entered from across the province. For the diamondback moth, officials are looking for insect flight information to give lead time on arrival of the crop damaging larvae stage.
Meers said the diamondback moth has three to four cycles a year, so it is a different survey insect. A three-week progressive map is used. Risk is noted each time there is a change.
Wheat stem sawfly is not an irrigation crop insect, and low incidence except in the southeastern corner of Alberta is expected this year.
The fear of grasshoppers is low in southern Alberta, but more are expected in the Edmonton and Peace River areas.
August rainfall could determine the 2010 impact of pea leaf weevils, said Meers. Sugar beets and pea fields are target crops, and while the population was fairly low early last year, by late May and early June the weevil had moved into crops.
“It was about as bad as we’ve seen it but the damage showed up late.”
If there is little rain in August, the soil will be harder and when larvae pupate the adults won’t get to surface easily and will likely die. If soil softens with rain, there can be a big invasion.
Cabbage seed pod weevil is very much an irrigated crop problem, said Meers. People working in agronomy in southern Alberta recognize that it has become a pest problem.
Farmers south of the Trans-Canada Highway can expect to deal with it, especially those with canola fields that flower first in their area.
Meers predicted late and hailed out crops will see high weevil numbers.
“If you have a canola field in southern Alberta in flower, they will find it.”
Meers said wheat midge deserves a cautionary note.
“We have not seen much of a problem. We see it with wheat planted after wheat when the risk of wheat midge goes up,” he said.
The last two years, the survey of irrigated fields showed that every third sample contained wheat midge.
“The message – wheat midge are in southern Alberta.”
He said the barley mealy bug could be a problem but farmers should realize the key management practice is rotation, rotation, rotation.
Reduced tillage can be good for mealy bugs, but broadleaf crops stop them because mealy bugs don’t eat them.
The cereal leaf beetle, found for the first time in 2005 near Lethbridge, has a wide range of hosts, he said.
“Numbers are really climbing and farmers should educate themselves to be able to identify adult cereal leaf beetles. The larval stage is when crop damage occurs.”
