REGINA – Blame it on mother.
This year’s bug bonanza is “Mother Nature at her finest,” said Manitoba agriculture department pest expert Bruce Murray. “It’s the environment, the wind and natural cycles of these pests.”
The Bertha army worm outbreak in Manitoba and eastern Saskatchewan is the worst since the early 1970s. Diamond-back moths have appeared in large numbers across the Prairies. Wheat midge numbers are high in some previously infested areas of Saskatchewan and Manitoba and a baby boom of the wheat-nibbling insects is being reported in areas that have never been affected before.
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It would be wrong to think this triple-headed pestilencial beast is caused by one factor, said Bob Lamb, an entomologist with the federal agriculture research centre in Winnipeg.
“I don’t think it’s anything that’s specific to this particular year,” said Lamb. The Bertha army worm is in the middle of a relatively predictable two or three-year outbreak and this is the second year, he said.
Diamond-back moths came with the warm air that travelled up from the Gulf of Mexico in mid-June.
“A lot of bugs that don’t belong here are here because of the winds,” said Murray.
Lamb said the eruption of wheat midge is probably due to good June rains in the eastern prairies. The midge hasn’t just suddenly appeared, Lamb said. It’s been here all along.
“If they don’t get these good rains, they just sit there and wait for another year, until conditions are right. They’re like a seed bank in the soil,” he said.
The coincidence of ideal conditions for the Berthas, the diamond-backs and the midges has created the pest extravaganza.
But it should not be considered simply an unusual situation that will not recur, Murray said.
A Manitoba entomologist who just retired after 33 years foretold this year’s pest problems, Murray said. “He said: ‘We’re going to get it here because it’s been too quiet for the past couple of years.'”
And while some pests are running riot across Western Canada, others are noticeably absent.
Aphids disappeared
Last year in Manitoba “we had aphid honeydew on everything everywhere.” This year “I’m having trouble finding any. Why is that? I don’t know.”
There are also few flea beetles. So few, in fact, that it is difficult for scientists to continue their work on crops resistant to the pest.
“Last year and this year we’ve been having people mail us flea beetles from Saskatchewan and Alberta just so we can get enough to work on,” he said. “It may seem that sometimes we’re hoping for these pests to come along, but we only want enough so that we can actually do the work on them.”
Regular field checks necessary
The Bertha army worm moth traps have alerted agrologists and producers in many areas, Lamb said. With traps in fields throughout western growing areas, “farmers can forget about Berthas for years on end so long as federal or provincial entomologists are on top of it and get the word out” when there is a problem, he said.
But the traps only tell producers if there is a problem in their area, not in their own fields.
Nothing can replace regular field checks and producers who fail to check may be ignorant of pest problems or end up using more pesticide that necessary, said Lamb.
“If they just spray based on what the (local) traps say, they may be wasting $1,000 or whatever it costs to spray that field.”
Although science has provided temporary measures, the only effective exterminator is Mother Nature.
Lamb said next year may see the end of the Bertha army worm outbreak, since natural parasites and viruses could spread widely enough.
The biological reaper might also be riding the heels of the booming midge population.
Since parasites and viruses tend to lag a year behind their hosts, it will likely be next year before it becomes clear whether they have caught up yet, Lamb said.
