Grasshoppers don’t announce themselves. You notice them the way you notice a slow leak — one day the fenceline grass looks a little thin, then the ditch banks look chewed, and by the time they’re clattering up out of the grass ahead of the pickup, they’re big, they’re everywhere, and they’ve already eaten the top off your summer feed. By then your options have shrunk to bad and worse.
Montana rangeland runs on grass you can’t replace once it’s gone. A dry spring followed by warm, settled weather is exactly what hatches a heavy grasshopper year, and those conditions show up plenty in this state. The bugs compete with your cows bite for bite, and in a bad outbreak they’ll take more forage off a pasture than the herd does. On hay ground they’ll trim the field edges into the crop, working inward, and the second cutting is usually where they hit hardest.
Get out and count them in June
The single most useful thing you can do is figure out how many you actually have while they’re still small. Grasshoppers hatch from eggs laid in the soil the summer before, and the young nymphs can’t fly — they hop, and they stay close to where they came out of the ground. That’s your chance. A nymph is far easier to kill than a hardened adult, and the population is concentrated instead of spread across the county.
The old square-foot method still works. Pick a spot, imagine a one-square-foot area a few steps ahead of you, walk up on it, and count how many hoppers jump out. Do that a dozen or more times across the pasture and average it. Hit the places they favor — south-facing slopes, road ditches, field margins, weedy draws, anywhere the ground warmed up early and the eggs got a head start. Nymphs cluster in those spots before they scatter, so those are also where a treatment does the most good.
What you’re trying to learn is whether you have a scattering of hoppers you can live with or a building infestation that’s going to strip the country. A handful per square foot is background noise on most range. Numbers climbing into the double digits, especially over a broad area, mean you’ve got a problem worth spending money on.
Deciding whether to treat
Spraying rangeland costs real money and it only pays if the grass you save is worth more than the treatment. On heavily infested ground where you’d otherwise be hauling in hay or pulling cattle early, it can pencil out. On thin, low-value range where you’d never recover the cost, it won’t. Run that math honestly before you call anybody.
The practical approach most people use on rangeland is treating strips or blocks rather than blanketing every acre. You leave untreated ground between the treated strips, the hoppers move through it, and you knock the population down without paying to cover the whole pasture. It stretches the dollars and it’s easier on the insects you actually want out there. Talk to your county Extension office and neighbors early — grasshoppers don’t respect property lines, and a coordinated effort across several outfits does far more than one person spraying alone while the ranch next door hatches a fresh crop.
Timing is the whole game. Wait until the adults are flying and you’re trying to hit a moving target that can leave the field, lay eggs before you get to it, and shrug off a spray rate that would have flattened a nymph. Every week you put it off, the bugs get bigger, tougher, and more spread out.
Watch the hay ground and the reseedings
New seedings and thin stands take the worst of it because there’s less total forage and the hoppers concentrate on what’s there. If you put in a pasture or a hayfield this spring, walk the edges. Grasshoppers move in from the field margins and the fencerows, so a border treatment along the perimeter will sometimes protect the interior without treating the whole thing.
None of this fixes a full-blown outbreak once the adults are up and flying. That’s the point. The year to get ahead of grasshoppers is the year you catch them small, count them honestly, and act while they’re still hopping and not yet flying. By August you’re just watching them eat.
