I’m going to talk about blister beetles, but I want you know know that problems of this kind start well before the first beetle arrives in my yard. It starts in January. You know what I mean. That’s when the pushers start showing up, the ones who have learned our weaknesses and seek to exploit them in every way possible. The seducers of winter dreams.
Seed catalogs. Oh, don’t pretend you don’t go through them page by page, item by item, lusting in your heart. It’s sad but true: no matter how many times you vow to not succumb, eventually you do.
I’m as guilty as the next person who — at least in January — believes she has a vibrantly green thumb. I get those seed packets and I can’t wait to lovingly place them in soil, gently water them, and watch as they push their bent stems up to the light.
And die.
Yes, well, it’s me doing the planting and my thumb turns out to be not so very green by the time I actually start any seeds. Plus my planning is… less than optimal. This year, though, things were going to be different. This year I planned to plan, and I wasn’t going to go overboard with the seed catalog. This year was going to be different.
This year I was going to GARDEN.
This year… yeah, wrong. This is the Year of Blister Beetles.
A couple days ago I noticed a few spotted blister beetles (Epicauta pardalis) I didn’t think much of it. Then this morning I went outside to water plants and discovered a veritable plague of blister beetles swarming in my yard — the only place that’s even a little green around here. Uh oh. When I went to water a goji berry bush that has been struggling since I planted it a year ago, I discovered that the beetles had hit it already, leaving behind a forlorn bunch of veins and stems. Goji berry bushes are tough, though, so I expect it will come back. Not that I’ll see any berries this year, darn it.
Next I checked out the dwarf golden delicious apple tree that has declined to blossom since the day I put it in the ground. It was supposed to be a pollinator for the Macintosh tree that has only ever produced one apple in 20 years due to lack of pollinators and drastic pruning by elk and porcupines. But I can’t blame the golden, either, since it’s close to the ground, easy munching for grasshoppers and blister beetles that have gone for it every summer since I planted it. The golden has had to use its energy for recovering and has nothing left for flowers. Between insects and various mammals, not to mention untimely frosts and summer droughts, I’m just amazed either tree has survived at all.
About those beetles.
Last year I had lots of grasshoppers that stripped the leaves off of my garden plants. This year I won’t see grasshoppers because blister beetle larvae eat grasshopper eggs. Cool, right? The bad news is that larvae become adult beetles, and adult beetles don’t eat anything but plant leaves. And they’re really REALLY hungry all the time.
The other bad news is that blister beetles are toxic — when threatened they ooze out a caustic chemical, cantharidin. If squished, the ick that is left is full of cantharidin. Did I mention toxic? Blister beetles are called that for a reason. Wikipedia says: “Cantharidin is an odorless, colorless fatty substance of the terpenoid class, which is secreted by many species of blister beetles. It is a burn agent or a poison in large doses…”
All too often horses are victims of blister beetle poisoning, which is even more bad news. There are hundreds of blister beetle species found in the US and something like 70 in NM and maybe more than that in Arizona, where lots of alfalfa is grown. Certain blister beetles (including the spotted kind) like to swarm in alfalfa. If they infest an alfalfa field, then when the hay is harvested beetles are caught up in the hay bales. Some will just die there but some will be crushed in the process.
Did I mention that cantharidin is very stable and remains toxic for a long time? As in years. Old bales, new bales, makes no difference, the toxic chemical is still there. Just a few crushed blister beetles can make a grown horse sick — imagine blisters in the mouth, down the throat, and into the stomach, and that’s just the beginning. Four to six grams of blister beetles can kill a 1100 lb. horse in just a few hours. There’s no antidote. It’s not a fun way to go.
The spotted blister beetles in my yard aren’t much of a risk to my horses since there aren’t any in the hay (NM and AZ commercial hay is rigorously checked for blister beetles). Plus the horses ate anything green near the barn long before the beetles arrived.
Nevertheless, the beetles are a clear and present danger to my plants — and to my own skin!
I mean, there I was in the middle of a blister beetle swarm, wearing opened-heel crocs with the holes in the toes. The critters weren’t just crawling — a few were flying, too! OMG! What if one landed on me and I brushed it off and it oozed on me? What if one got down my shirt or in my crocs and I squished it? Suddenly my feet and exposed skin felt super vulnerable. A couple beetles are one thing, but that many is too many! EWWW!
I fled into the house to Google the situation and discovered that diatomaceous earth (DE) will not only kill blister beetles but also repel them — or so a few websites say. I have a flour sifter dedicated to spreading DE for fly control (I’m not impressed with the results) and have already applied some to the swarm area and then retreated back to the safety of the house. I checked a few hours later and found no beetles anymore but also no dead ones. Maybe they moved on. Far away. I hope.
Google keeps thinking I mean The Beatles, not the beetles. And that reminds me. Blister beetles aren’t the only insect that produces cartharidin. Ever hear of Spanish fly, source of one of the original Viagras? Spanish fly comes from a beetle, not a fly, but it does give men long-lasting erections. (Buzzards eat the beetles for the same reason, by the way).
There are a number of serious side effects, mind you. Stuff like vomiting, seizures, coma. Oh yeah, and death. Just sayin’.
https://www.historyextra.com/period/ancient-history/love-potions-aphrodisiacs-facts-spanish-fly/