Death Comes For the Grasshopper(s)

Not surprisingly after 3 hot, dry years, there have been a lot of grasshoppers around this summer.  Grasshoppers and hot, dry weather go together like bread goes with peanut butter and jelly.  I've been noticing a few things that bode a little better for next year, though, and I'd like to share them with you.

The beginning of the summer started with literal hordes of grasshoppers, especially newly hatched nymphs.  The photo above shows a phalanx of said nymphs on a soon-devoured broccoli leaf.  It wasn't uncommon to have hundreds of tiny grasshoppers flying up with every step through grassy areas. 

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....

During warm, wet weather, there is a naturally occurring fungus, Entomophthora grylli, which infects grasshoppers and causes them to climb to the top of vegetation and grasp the stem with their legs, then die.  I've been seeing quite a few grasshoppers seemingly mummified like this.  The best news is that, as these grasshoppers dry out, the fungal spores spread on the wind to other grasshoppers, infecting them as well.

So not only is there one less grasshopper reproducing for next year, but each one that dies like this has also potentially caused other grasshoppers in the area to die as well!  Rather nightmarish...but effective.

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. 

I've got a large population of wheel bugs this year;  after such an abundance of prey, I suspect I'll have an even larger population next year!

Spiders, too, eat grasshoppers.  This photo of a black and yellow garden spider eating a grasshopper was actually taken last October, but I'm sure that the spiders I'm seeing this summer are taking out quite a few grasshoppers as well.  (My garden spiders aren't this big yet, but they will be!)

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.

I occasionally see 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.

The first summer or two that we lived and gardened here, we started our vegetable garden.  Despite the tall grass that we encouraged to grow on much of the property, we didn't see a large number of grasshoppers.  Some, yes, but not enough to cause noticeable damage.  Generally, our garden plants did superbly, although the tomatoes, in particular, attracted large numbers of black blister beetles.  A few grey blister beetles came too.  Not only were these insects a little creepy looking, but they ate the tomato leaves and made the tomato plants look really ugly.  I still harvested more tomatoes than I could possibly use and there weren't enough blister beetles to defoliate the plants, but definitely there were enough to make the plants look ratty. So I started to handpick the blister beetles, dropping them in soapy water to kill them.  Each morning I would do this, and it wasn't unusual for me to dispatch 50 or 100 each day.  It definitely lessened their populations over the course of the summer.

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.

In June, 2011, we came back from a trip to San Antonio to find several masses of hundreds of striped blister beetles writhing on our front lawn, presumably in an ecstasy of mating.  Our only thought was how to dispatch them as quickly as possible before they, too, started to eat the leaves of our tomatoes and other plants!  So we put soapy water in our shop vac and vacuumed most of them up.  Problem solved.

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 every adult blister beetle you see, an average of 27 grasshoppers don't get born.  What had we done?

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.
 

This year I'm finally seeing black blister beetles on the tomatoes and a few other plants again.  Mind you, I'm not seeing them in huge numbers, but they are there and they are reasonably common.  This year I'm NOT picking them off and killing them.   I'll share my tomato leaves so that, hopefully, the black blister beetle larvae will be feasting on grasshopper eggs over the winter!

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.....