Now, towards the end of July, there are still a lot of grasshoppers, but the numbers seem to have declined a bit - dozens fly up at every step instead of hundreds. Sometimes only a few fly up. I haven't sprayed or made any effort to curb their numbers, so what has happened?
First of all, the weather has been cooler and wetter than during the last 3 or 4 summers. Cooler, wetter weather is good for plants, but bad for grasshoppers. Newly hatched grasshoppers can be killed by cool, wet weather. Truthfully, I'm not sure we were cool enough or wet enough for this to happen this year, but I'm mentioning it anyway. However, warm, wet weather can also have a negative effect on grasshopper populations....
Predators have been playing a role in decreasing grasshopper numbers, too. Just in my ramblings with camera in hand, I've caught shots of several wheel bugs eating grasshoppers.
Birds, not surprisingly, eat grasshoppers as well, although I haven't been lucky enough to get any photos of that happening. Bluebirds, quail, pheasant, meadowlarks, lark sparrows, and lots of other birds are known to eat grasshoppers.
great golden digger wasps around the yard, as in this rather out-of-focus photo from about a week ago, hunting (in this case) on Bradbury beebalm. If these beautiful, big wasps aren't feeding themselves with nectar and pollen on flowers, they are actively prowling for grasshoppers to sting and paralyze. Once the grasshopper is paralyzed, the female wasp takes it back to her nests as baby food to lay her eggs on.
The long and the short of it is that grasshoppers are grazers on plants, and a lot of animals eat them. With bison no longer freely roaming the prairie, I understand that grasshoppers are actually the primary herbivore for this important ecosystem! Because grasshoppers are so mobile, it's hard to kill them with insecticides. Ironically, it's much easier to kill the insects that prey on grasshoppers - so any time you spray an insecticide, even an organic one, you are probably helping to increase grasshopper populations, in the long run, by decreasing their predators.
Speaking of spraying insecticides and accidentally killing off insect predators, the last grasshopper predator I'm going to show you today fell victim to some actions Greg and I took several years ago before we knew any better. While we didn't actually spray, we did kill enough of these predators that their population declined around our yard and gardens for a few years, so we've actually had more grasshoppers than we would have had if we hadn't tried to solve a "problem" we were sure we had.
Even after I learned that blister beetle larvae ate grasshopper eggs, I continued to handpick the blister beetles, reasoning that I was seeing plenty of blister beetles, so it shouldn't be a problem.
By later that same summer, I was seeing very few blister beetles...but hordes of grasshoppers. As you may remember, the summer of 2011 was horribly hot and dry. We had 53 days over 100 degrees F. and almost no rain. By late July of that year, our althea had been defoliated by the grasshopper hordes.
For several years now, we've had so many grasshoppers that by early summer most of our vegetable garden is gone. Once the grasshoppers hatch out, they devour the spinach, kale, broccoli and cauliflower within days. Then the onion and garlic go. The asparagus stalks become dried brown sticks with all the green gnawed off. Over the course of the summer, all the iris leaves get whittled down to nubs. Thankfully, 2011 was the only year our althea were entirely defoliated, but their leaves have been severely chewed each summer since then.
The more I learn, the more I realize that I don't know very much. A blog post I read over the weekend was talking about tangleveined flies as a grasshopper predator. That's a new species I don't recognize, so now I want to learn more about them and see if I have any of those grasshopper predators in the yard.
There is an incredibly complex web of plants and animals that will generally keep each other in balance and keep the Earth healthy, if we leave enough of them alone to "do their thing." We humans, though, get pretty cocksure of ourselves and start killing plants and animals off, thinking we know a lot and can surely manage better than Mother Nature does.
We're not as smart as we think we are.
Hopefully my yard is getting back into balance a bit better again. Ah, the gardening spirit never fails, does it? Next year will be better.....