As the temperature climbs and crops start to emerge, various insects are chewing fields in parts of northern Alberta.
Jennifer Otani, an Agriculture Canada pest management biologist, said she has seen flea beetles in her research field plots and farmer’s fields near Beaverlodge, Alta. Numbers range from zero to 25 flea beetles per card within spring-seeded fields of commercial canola.
“We’re doing the monitoring to figure out if lots on the sticky card means huge problems in your field. In some situations it’s meant no and in other situations it’s meant yes,” said Otani.
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“In the Peace, we’ve had some problems with flea beetles in canola, but one or two fields here and there as opposed to a whole area. This would be three years in a row where we’ve had good numbers, a few fields that had to be reseeded and some that were sprayed.”
The reappearance of glassy cutworm in some established stands of timothy may be of more concern.
“In 2000, we had a fairly large infestation, covering a large geographical area in the Peace. That affected creeping red fescue, pasture and hay. If you were growing grass in the Peace you had a problem with glassy cutworms in 2000,” said Otani.
“This year we’ve seen a few stands around Spirit River and to Falher. These were all older stands of timothy with glassy cutworm damage and a few had to be reseeded.
“By this point in the season, the larvae we’re finding are ready to pupate. The feeding damage has been done for the year. If someone called and asked me about spraying, I would say ‘don’t bother because they’re
pupating.’ “
While there was a huge glassy cutworm problem in 2000, Otani said when it came to the growing season of 2001, it turned out to be no problem at all.
“It may be a function of the year, but with this pest it seems to be all of a sudden, then nothing. What we found in 2000 was that some of the populations of these glassy cutworms were heavily parasitized by beneficial insects, so that may be what’s happening.”
While Otani said most of the feeding damage is done for this year, it’s something to watch for next spring.
“There were a couple of fields that looked very good this spring, then over a seven-day period they browned right off. It may not be visible early in the spring, but what we saw was the end of May to the beginning of June.”
Along with the glassy cutworm, Otani said farmers should watch for damage from cutworms in annual crops.
“I’ve heard reports of other cutworm species in crops like canola. If they’re missing rows, it’s something to investigate.”
While they’re not at problem levels yet, and may not be this year, Otani said grasshoppers are just starting to emerge.
“Other areas of the Prairies seem to have got a bit more moisture. But some of the areas in the Peace are a little bit drier and we’ve been a bit warmer. So definitely watch for them,” she said.
“A couple of second instar two-striped grasshopper nymphs turned up in a ditch. Not huge numbers, but this indicates they’re hatching, so start watching field margins.”
Otani said because wireworm larvae are found across the whole field, scouting for click beetles should not take place only on the field perimeters.
“With them, there’s not much you can do for this year, but you want to be looking at treated seed for whatever you put in there next year.”
Otani said lygus bugs are turning up earlier this year.
“With lygus, you usually need to wait until the end of June or beginning of July before you’re looking at economic threshold numbers.”
She saw lygus bug nymphs at the second instar stage in clover.
“This seems a little early in the year for this stage to already be making an appearance. Odd too that there weren’t any alfalfa plant bug nymphs visible in the same clover because they’re usually present earlier in the season compared to lygus bug nymphs.”
In southern Alberta, Héctor C‡rcamo, a research scientist dealing with insect pest management at Agriculture Canada in Lethbridge, reports that the most obvious insect problem is pea leaf weevil.
Thousands of pea acres have been, or are being sprayed, especially around the Foremost area. There have been reports of damage to alfalfa seedlings but those have not been confirmed.
He said a live cereal leaf beetle was collected near Lethbridge, indicating that it managed to overwinter.
C‡rcamo said wheat stem sawfly adults should start flying in the next couple of weeks. With more farmers planting solid stemmed wheat varieties, that should help minimize damage from these pests.
He said cabbage seedpod weevils are numerous in cruciferous weeds like flixweed and should be watched in canola, especially early planted fields.
Lygus bugs are average or below average, less than one per sweep in weeds. They were around the third instar in early June, which is normal for southern Alberta. But because of their explosive nature, farmers should watch for them if the weather gets hot and dry, especially in late planted canola.
Flea beetles have been slow to emerge in southern Alberta. In two of three fields he monitors intensively, insect populations were low with no noticeable damage on seedlings. He said this insect can be more pesky in late planted fields in the area.
Aphodius beetles are beetle grubs that occasionally are abundant in turf that has lots of manure. C‡rcamo said they are not pests but beneficials that break down organic matter.
Other insects, such as cutworms, diamondback moths and bertha armyworms, might show up as localized problems but he has not heard any direct reports.
