August 28, 2015

Shot hole, aka Coryneum blight, is tearing up our cherry tree and likely was a disease the tree brought home from the nursery.
Cyn Cady

Something or someone is doing damage to my cherry tree, and it’s time to find out what’s going on. I’ve examined leaves and scraped around in the soil and didn’t find the culprits, so there’s only one thing left to do: a night mission.

Critters and creepy crawlers that can’t be found in the light of day become bold adventurers at night, slinking out from their hidey holes and attacking innocent plants—kind of like tiny vegetarian vampires, except way less cool and without the awesome cloaks and tuxedoes and whatnot.

Since neither Van Helsing nor Buffy are apparently available for nighttime bug-pire hunting (they did not return my calls), I decided to tackle it myself. Armed with a headlamp and a spray bottle full of a fresh batch of insecticidal soap, I waited patiently for dark.

(Basic bug soap recipe: 1 tablespoon Dr. Bronner’s castile soap and water in a quart sprayer, but you can add cayenne, vegetable oil and even garlic—I told you they are like little vampires!—to kick it up a notch.)

As I crept toward the cherry tree, my trusty dog Holler at my side (who am I kidding: he’d be useless in a vampire attack—he probably just wanted to see if I had any snacks), headlamp aglow, I began to feel the thrill of the hunt.

It was a bit of a disappointment. I fully expected to find a large and scary-looking insect culprit, munching away on a delicious leaf. Instead, I only found one tiny thing that looked like it might be some kind of mite. I smushed it, but it was not very satisfying. I didn’t really think that this itty bitty critter could possibly be responsible for chomping holes in leaves all over my little tree, so I went back inside and hopped on the information highway.

Turns out, my little fella is infected with shot hole. Shot hole! Sounds like some kind of backyard game, but nope, it’s a fungal disease that creates holes in leaves that resemble insect bites. It’s also called Coryneum blight. Strangely enough, it’s usually a fungus that occurs in places with a wet, humid spring climate, which is pretty much opposite of what we’ve been experiencing here … it’s been hot and dry, so I am guessing the tree came from the nursery with it, even though it appeared completely healthy when I bought it.

For an organic orchard, the treatment is to remove all infected leaves and apply a copper fungicide, which also can be used to treat the fire blight that has re-infected my beloved pear tree. So I will put away my bug soap and my vampire analogies and go after the fungus among us, which is not nearly as much fun as sneaking up on night-feeding bugs with a headlamp and an overly friendly lab mix. Perhaps I can pretend I’m going after the Blob.

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