Dirge in A Miner
We could not be prouder of our spinach if they were our own children. Maybe prouder.
Look how thoroughly green and upright! Look at those beefy crinkles so chockfull of vitamins! We’ve got a dozen of these stalwart, early-spring rascals actually growing in our garden. We did something right!
Look underneath the leaves. What are those tiny white dots? And over here on this plant, why are these leaves so scabby?
Yes, just when a gardening triumph seemed so close, so graspable, it slipped from our fingers like (insert sports analogy here in which a team on the verge of winning blows it). Our spinach is being attacked by Pegomya hyoscyami, the spinach leafminer.
This is an insidious pest that arrives as eggs deposited by a momma fly on the undersides of spinach leaves. Those white dots we noticed are the egg clusters. On extremely close examination, the clusters reveal themselves to be rows of itty-bitty eggs.
These little eggs eventually turn into maggots that look like adorable miniature white carrots. But they are neither adorable nor carrots. These 1/4-inch-long larvae eat their way in between leaf layers (spinach leaves have outer epidural layers and a soft munchable inner layer). Once inside, the larvae begin to tunnel around, plumping themselves up on vitamins that are rightfully mine.
Their tunnels appear on the leaf surface as brown and gray scars. When sated, the bugs drill escape holes and drop into the surrounding soil. From there they mature into flies that buzz around, mate, and in one of Nature’s infuriatingly dependable cycles, alight on spinach leaves to begin the process all over again.
According to various gardening experts, there’s no surefire remedy, unless you don’t mind soaking your vegetables in pesticides—killing off beneficial pollinators in the process—and eating carcinogenic materials. Over on this side of the fence, we’re pretty organic, mostly because it’s less work—you can just sit back and let things happen, and when your lawn becomes weed-infested and your garden beds are drooping and scarred you can proudly claim,
But we’re organic!
Back to remedies:
• Cover seedlings with fine-mesh netting to prevent flies from laying eggs on the leaves.
• Pinch off and destroy any leaves with scars.
• Introduce beneficial insects that feed on leafminer larvae. Parasitic wasps such as Diglyphus isaea kill leafminer larvae before they pupate, and ladybugs will feed on them, too ( although I’m not sure how you train winged insects to stick around your garden when there’s a whole neighborhood out there to explore).
• After harvesting, till the soil to destroy lingering larvae and help prevent an infestation of the next crop.
• Spray leaves with Neem oil. Neem oil is supposedly an organic pesticide that, when properly applied, is harmless to humans. Although the unspoken implication here—with a caution about improper application—seems to indicate that Neem may not be all that benign. Anyway, Neem odor is like a cross between paint stripper and rotten apples, and if you’re whipping up a salad for people you don’t ever want over for dinner again, that’s the way to go.
I’ll admit that prior to the discovery of our leafminers, we did enjoy a just-picked, garden-fresh spinach salad, so if there are any ill effects to be had from ingesting raw Pegomya hyoscyami, I’ll try to let you know before the paralysis sets in.
But now, in the warm light of new knowledge, we carefully scrape off the egg clusters, leaf by leaf, and discard leaves with any signs of scarring. Then a thorough washing. And we’ve developed a fondness for steamed spinach. Which only underscores the old adage, When Life gives you leafminers, sterilize.