This grasshopper munching on a sunflower in southwestern Manitoba is being devoured by parasitic red mites (Eutrombidium locustarum), says Manitoba Agriculture, Food and Rural Development (MAFRD) entomologist John Gavloski.
The mites feed on the blood (hemolymph) of grasshoppers. They also prey on grasshopper eggs. Each female mite can lay up to 4,000 eggs, providing mite populations the potential to increase rapidly and substantially as grasshopper populations increase.
Research in Montana has shown that these mites can reduce the survival and reproduction of grasshoppers. Red mites are fairly common this year, Gavloski said.
Lionel Kaskiw, MAFRD’s farm production advisor based in Souris, said one in seven or 10 of the grasshoppers he saw recently in a sunflower field last week had the mites. This particular field had a high number of feeding grasshoppers on its edges. Gavloski said it doesn’t usually pay to spray grasshoppers in sunflowers until there is at least 25 per cent defoliation.