Can’t get no satisfaction
This year I’m trying a few things to reduce my gardening effort. This includes putting in an irrigation system. But mainly, this involves efforts to suppress some plant diseases and insect pests that plagued me last year.
Whenever it’s feasible and doesn’t cost much, I try to test what I’m doing. It’s too easy to fool yourself into thinking that something worked, when, in fact, what you’re observing is just luck or normal year-to-year variation.
That’s particularly true when you try something in response to a really bad problem. Say, an infestation of some insect, or a plague of some fungal disease. Many things naturally exhibit “regression toward the mean”. Your absolute worst or best case will never continue indefinitely, but will typically drift back toward some long-term average. (Or, putting that another way, the long term average is the result of such drift, take your pick.) And so, a particularly awful year for fill-in-the-blank is apt to be followed by a year that isn’t quite so awful. And it’s easy to mistake that natural variation for the impact of something you did.
But here’s a weird thing: If a problem simply disappears on its own, all your effort to try to test some treatment is wasted. You carefully establish your treatment and control groups. Or you count on having some baseline level of the pest present in your garden. And then, to test the impact of your treatment, you see whether your “treatment” plants do better than your “control” plants — those that you left alone.
If that pest or disease remains present in your garden, that treatment-versus-control comparison is good science. (Plus-or-minus the issues caused by small sample size, assuming you chose your areas randomly, and so on.)
But if that problem simply disappears for a year, the treatment-versus-control comparison tells you nothing. Your treatment was for a pest or disease that simply didn’t exist in your garden, that year.
In some sense, you need the aggravation. You need whatever it was that prodded you into action to stick around and continue to be a pain. Without that continued aggravation, there’s no test of whether or not your treatment did anything.
But beyond the science, there’s also an issue of satisfaction. You want to look at whatever the problem is — the bugs, the mildew, the rot — and say, ha, beat you. (Well, when it comes to bugs, what I want to say is “die, you bastards, die”. By contrast, fungal diseases don’t bring out quite the same primal urges.)
But with no mortal enemies, the can be no gloating over their corpses. The upshot is that the Garden of Eden would have been a useless place for testing fungicides and pesticides.
Citric acid versus copper for control of powdery mildew — first respray.
What brings this up is a couple of experiments I have going on in the garden this year.
First, I’m growing cucumbers and summer squash in an insect-proof enclosure. These are parthenocarpic varieties, that is, they’ll set fruit without pollination, so (in theory) I’ll get fruit even though I’ve prevented the bees from reaching the plants.
That seems to be working just fine. The plants are healthy, and the squash are indeed setting fruit now.
And yet, there’s something lacking. What I wanted to see was squash vine borers and cucumber beetles covering the outsides of these enclosures, pining for the goodies within. But unable to reach and destroy them. What I’m actually seeing is bupkis. So far this year, I’ve seen exactly one squash vine borer and one cucumber beetle. That was weeks ago. (And for the cucumber beetles, I know they aren’t here because they cluster in the squash blossoms in the morning, and I have yet to see anything but bees there this year.)
So, aside from the lack of satisfaction, I can’t say whether this worked or not. After a dreadful 2021, this year I’m living in a cucurbit Garden of Eden. Which means I can’t really say whether or not these enclosures worked. Because the pests I built them for are vacationing elsewhere this year.
And then there’s mildew. I mean, damn, if you can’t rely on mildew, what can you rely on?
For the last two years, around this time, I was either frantically searching for some home remedy that would address the powdery mildew that was destroying my cururbits. Or I was pruning out literal armfuls of badly infected leaves every day. That stuff spreads like wildfire in my garden, and it’s clear there’s a lot of it harbored in or around my garden.
But 2022? Now that I’m ready for it? Crickets. I have pumpkins, summer and winter squash, and cucumbers. And so far, the extent of powdery mildew is some modest little dots on some winter squash leaves.
Here’s the state of my butternut squash patch, at the first respray, five days after spraying copper solution and citric acid solution on it. Top picture is the original, second one is the respray.
So, that’s great. I have almost no powdery mildew on the side sprayed with extremely dilute citric acid. And almost none on the side sprayed with a commercial copper-based fungicide.
Success? No. Too soon to tell. I still have almost no powdery mildew on the middle section that I left untreated. Again, I can’t say whether this works or not. Because I don’t seem to be having that problem, this year. Yet.
Conclusion: Yeah, count your blessings and all that.
Sure, I should be glad that my garden isn’t being hammered by these problems this year. I’m really not rooting for the mildew or the bugs to return, just so I can test my methods.
This year, I went to some effort to get some answers. Will I be able to stop powdery mildew in a bad year, stave off vine borers and cucumber beetles when there’s a plague of them?
The honest answer is, I have no clue. Nature fooled me, not with a plague, but with the opposite. The bottom line is that you can’t test pesticides in the Garden of Eden.
