OLDS — Don’t be too quick to spray your crop to kill pests, there may be bugs out there that’ll kill them for you, says Scott Meers, a retired provincial insect management specialist.
Meers gave that message in a session called Good Bug, Bad Bug during AgSmart, the Agri-Trade Equipment Expo Group's educational agriculture exposition, held last month at Olds College.
Meers said certain bugs view crops as “this massive food resource.”
“If you're a wheat stem sawfly flying over the field of wheat. Guess what? That's a food resource and you have to always keep that in your head,” he said.
But on the other hand, pests like the wheat stem sawfly are a food source for other insects.
The same goes for aphids.
“We get lots of other general predators, like certain flies, lacewings, and there's a lot going on,” Meers said.
He said spraying to kill crop-eating pests is rarely the answer, because by doing so, farmers kill beneficial insects that would have done the job for them.
Meers predicted the grasshopper population will be “huge” this season.
He said they too have several natural enemies, such as the hoverfly, the bee fly and one he called the “hairy butt fly.”
“The most distinctive feature on them, they look like a fly with a hairy butt, but there are a whole host of hairy butt flies that specialize in grasshoppers,” Meers said.
“If you're in a grasshopper area, you would have seen these. They like to get in your truck as soon as you open the door.”
Insects aren’t the only enemies grasshoppers face. Meers said entomophaga grylli, a fungal pathogen, can infect and kill grasshoppers.
“Last week in a square foot I saw 10 dead grasshoppers going into the top of the plants. Now why are they the top of the plant?
“Ecologically, for the fungus, makes sense to be up as high as you can get to spread your spores, right? So there's something in the fungus that takes over the brain of the grasshopper and forces it to the top, and they die up there, and then the spore is spread out,” he said.
Meers said that pathogen has killed many grasshoppers in the northeast part of the province.
“Whether we're going to get enough this year to do it in southern Alberta, I don't know, but the numbers of this are really growing,” he said.
“For God's sake, don't spray, because look at all the all the things that are going on,” Meers said.
“Do you want to work with your natural enemies or work against them? Do you want them to work for you? Because they're there. We know they're there. Every time I go to the field, I see them. It's warfare out there.”
