05 Aug It Takes a Village to Repel a Pest: Crowdsourcing Our Aphid, Inchworm Invasion
Remember our darling, hangover-curing loquat tree?
About a month after we picked its last fruit of the season, our tree was attacked by a horde of green apple aphids. It happened almost overnight: One moment the loquat’s foliage was broad and lustrous, and the next its leaves were shriveled and curled, scaly with hundreds of winged Aphis pomi.
It is true that onto every garden a lot of aphids must fall. But we’ve never had this problem with our loquat; drooping, dehydrated leaves used to be the worst of its troubles.
Should we buy some ladybugs, we wondered? No, says @BugladySuzanne in this compelling TreeHugger article, arguing that those ladybugs for sale at hardware stores are wild harvested and often carry infectious parasites. We were just beginning to wrap our minds around our yard’s insect aggressors when we were hit again, in the herb garden.
Turns out that some sneaky little varmint has been eating our sage.
Within two weeks of installing our industrial-modern vertical herb garden (photos to come, we promise!), we spotted munch-marks along the margins of our two Salvia officinalis varieties — without a culprit in sight.
Our sage’s cartoonish chomp-marks were left by a…? This calls from some social media CSI.
So we escalated the issue up to the old legume gallery. In the #GardenChat community on Google Plus, we got our first diagnosis: Slugs and grasshoppers.
But aren’t grasshoppers supposed to be repelled by sage? Not if they’re really hungry, the internet replied. We knew about the old beer-in-a-jar trick to kill slugs (they’re attracted to it, and will crawl in and drown), but what to do about the ‘hoppers?
“Organic fix for hoppers: guinea hens or chickens!” our G+ friend suggested.
“I wish!” we said. From your mouth to our landlord’s ears.
We also consulted the indispensable New Sunset Western Garden Book. The section on pest management includes helpful photos of offenders and the chewed-up evidence, along with a list of beneficial insects, natural pesticides, and tips on pruning and handpicking.
The photo we submitted to the legume gallery that is Instagram.
The search for answers continued on Instagram. Within seconds of posting a picture of our Salvia ‘Swiss cheese,’ assistance came in a warm, compassionate, confusing wave:
“You are better off drinking the beer and picking them off with a headlight at night.”
“Sluggo works well; don’t use salt.”
“I’ve heard Sluggo is very toxic to birds, […] so I use crushed eggshells for the snails.”
“That does not look like slugs to me, to be honest. Do you see slime trails?”
“Have you noticed droppings?”
Per the suggestion of our friend and accomplished gardener @Warrensgarden, many of the holes — especially the smaller ones — indeed resembled the handiwork of a flea beetle. A few days later, we found an impossibly small green inchworm (actually a moth larva) inching its way along the foliage. And then we discovered a cocoon on the underside of a leaf.
The inchworm cocoon. Is that a parasitic wasp we also see? Caterpillars, which are not inclined to eat sage, will chomp on the herb to self-medicate against parasites.
Had the slugs and grasshoppers been falsely accused?
We picked off the caterpillars individually. For the beetles, we sprayed the sage leaves with diluted neem oil. A product of the evergreen neem tree, the oil is used in Ayurvedic medicine to treat conditions like acne, parasites and malaria, and in organic gardening to repel bugs like aphids, beetles, mites and whiteflies, and diseases like powdery mildew, without being harmful to mammals.
Note that neem oil should be used with care if beneficial insects like bees, ladybugs and butterflies are nearby. It should also applied in the late afternoon or evening to avoid contact with day-active beneficials, and to prevent the burning of tender leaves.
We’ll let you know if this works!
Back to those aphids. We recently brought home a monarch-friendly milkweed; it came with festive red and yellow flowers, and a healthy coating of bright orange aphids. The bugs formed almost a solid coating around the stems of the plant and the undersides of the freshest leaves. (Our two monarch sightings last week made it all worth it.)
Truth be told, there is something weirdly appealing about watching these buggers wiggle in place.
They are oleander aphids to be exact, and are “inevitable” on milkweed, a staffer at one of our favorite nurseries informed us. He said to forget about the neem oil in this case, and to just spray infested areas with a strong jet of water. Same goes for the infested loquat. Another trusted source suggested sliding the bugs off the milkweed by hand and squishing them between our fingers. According to Gail Langellotto of OSU Master Gardener, there’s a biochemical perk to doing this. She writes:
“During Master Gardener training classes, I’ve often lectured about the benefits of ‘popping’ aphids. Squish an aphid, and you magically attract parasitoid wasps […] Some species of aphids release alarm pheromones when they are crushed. The alarm pheromones send a signal to nearby aphids: ‘Abandon ship! We’ve been found! Parachute to safety, or else be eaten!’ ”
Sage advice. We did as Gail, a Master Gardener with a Ph.D. in entomology, advised. The bugs squished easily into a saffron-color grease that dripped down our gloves; animal lovers that we are, we must admit this is our favorite method so far.
We might find our way out of this wormhole yet. -TH