Just leave benefical grasshopper species alone, says leading hopper entomologist
By Tim Kalinowski
Despite reports of pockets of grasshopper pest outbreaks in southern Alberta, Dan Johnson, an entomologist with the University of Lethbridge, says the news in that regard isn’t all bad— alongside the rise of these pest species other, more beneficial, grasshopper species are also having a bumper year.
“There is two interesting things going on,” says Johnson. “As the weather changes a bit, certain pests, and not always the same pests as before, have been shooting up and of interest. But there is a whole suite of beneficial grasshoppers that are also increasing. There are several that attack weeds, and in fact they would die in the presence of crops if that is all they had.”
Johnson gives an example of one of these species he is seeing out in ditches and in the southern Alberta hills: Turnbull’s grasshopper.
“The Russian thistle grasshopper, which in Canada is called Turnbull’s grasshopper; it’s numbers have also increased in recent years to the point I have colonies where I am finding the immature stages and the adults, and they are actually feeding on Russian thistle. And almost nothing out there eats Russian thistle. Maybe goats and Turnbull’s grasshopper; that’s about it.
“Will they wipe out Russian thistle? No. But it is interesting there are hoppers, like the Turnbull’s, that do these sorts of things. They also eat kochia, and all the other species do not.”
Prior to this year, Johnson had seen relatively few of them. Finding them in greater numbers, he admits, took him slightly by surprise.
“They are all over southern Alberta where there is dry rangeland and Russian thistle growing,” Johnson confirms. “They are normally extremely rare, but lately I can go out and find them. It’s an interesting story.”
Other beneficial grasshoppers on the rise this year uphold the Prairie eco-system in an even more important way, says Johnson.
“There is a large group of hoppers that are really important food sources for grassland songbirds,” he states. “One reason grassland songbirds have been in decline, according to the bird experts who monitor them, is the decline in the food supply.”
Johnson says its important for farmers who may have noticed greater grasshopper numbers on sections of their lands to be sure which species they are seeing before taking more drastic measures.
“We do want the eco-system to have insects,” he says. “We just don’t want it to have insects that cost money and result in the use of insecticide.”
Johnson reminds readers any grasshopper with coloured wings is not a pest. Anyone that sings or scritches or clicks are not a pest.
“Having grasshoppers isn’t necessarily a problem, but what you need to do is see if they are damaging vegetation severely,” he says. “If they are not, then they are probably the ones who aren’t an issue. And like I say, some of them we really do want to see return and say, ‘hi,’ because they keep the birds alive.”