“What a pretty white butterfly!” said Kathy, a visitor from Minnesota. She was touring our garden recently on a warm sunny day when all manner of insects were out and about.
“For each one you squish, I’ll give you a dollar,” I told her.
“Wow, that’s quite a reward.”
“It’s worth it. Those butterflies are also called cabbage moths,” I said. “They are not welcome here. They lay eggs, which hatch into green worms that eat cabbage, radish, broccoli, you name it.”
One of Kathy’s kids picked up on the one-dollar reward and took off after a moth that was fluttering across the yard.
As we finished walking around the garden, I couldn’t help strategizing in my mind. Time to go on “moth watch.” Sure enough, two weeks later, I spotted a velvety green caterpillar on a radish leaf.
Now common through across Europe, North Africa, Asia, Great Britain and most regions of the United States, the imported (accidentally introduced in the 1850s) “cabbage white butterfly” or simply “cabbage white” is a small to medium-sized butterfly of the whites-and-yellow family Pieridae. It causes extensive damage to cabbage-family crops in gardens and commercial fields. Although the green larvae is slow-moving, it is extremely destructive, especially if it’s allowed to gain a stronghold. Not to scare you, but I’ve heard that a single female of this species can generate a few million generations.
It had been several years since I’d seen cabbage moths (I have a hard time granting them the exalted status of ‘butterfly’) fluttering about the garden.
The cabbageworm (Pieris rapae) has a classic, multi-stage life cycle: Adult females emerge in early spring (May-ish in Kodiak) after over wintering as green pupae. They lay about 200 tiny yellow eggs on host plants — usually on the undersides of leaves. Take that as a clue. These hatch in a week (depending on temperature) into young larvae caterpillars.
The larvae are eating machines, feeding heavily for 15 or more days, feeding
on the surface layer of leaves which leaves a translucent, tissue-like scars. As they grow, they chew large, irregular holes usually beginning on the outside leaves of cabbage and other cole and mustard crops (broccoli, cauliflower, kale, turnip, radish). As the worm feeds, it commonly bores into the center of cabbage heads contaminating them with its fecal pellets. The dark-green pellets can also be found in the crook of leaves near the stem. Another clue.
After all that feeding, they pupate on lower leaf surfaces or garden objects. After 10 days, a new generation of butterflies emerges. There can be three to five overlapping generations each year, as many as eight in a warm year.
How to control cabbageworms?
Here’s where you should love yellow jackets and parasitic wasps. These are the cabbageworm’s natural enemies along with spiders, birds (including chickens and ducks), and beetles. You can protect plants with floating row covers to prevent adults from laying eggs. And remove leaves (and damaging worms). Citrus and ammonia spray works well, too.
What about spit bugs?
This time of year, we all get reacquainted with spit bugs, or spittle bugs. They are easy to identify and get their name from the clear, bubbly foam masses in which the immature bugs, or nymphs, hide. So if you go hiking, you’re likely to get a little damp, even on a sunny day, if you know what I mean.
Fortunately, they’re not a ‘bad’ pest like slugs, cabbageworms or aphids. Oh sure, a heavy infestation (we’re talking thousands or millions) can cause distorted leaves or stunted plants but this damage is only temporary and the plants generally outgrow it.
The best solution is to tolerate them. If you’re really grossed out by spittle bugs though, blasting with water or hand picking (ick) the few insects are often the best controls. Note that soap sprays don’t work very well because the froth shields the bugs from enemies and the sun.
How to know when to harvest garlic
Determining when garlic is ready to harvest is one of the trickiest parts about growing it. If you harvest too soon the cloves will be small and underdeveloped (certainly usable but not as big and plump as possible). If you wait too long, as the heads dry the cloves will begin to separate and the head won’t be tight and firm. This is not a disaster, but the cloves will be more vulnerable to decay and won’t store as long.
By the way, garlic flower stalks, or scapes, are excellent sautéed or made into a pesto with parmesan cheese, olive oil, salt, lemon juice, roasted walnuts and a little fresh ginger.
The garden calendar
Kodiak Garden Club’s annual garden tour: Aug. 1 and 2. Stay tuned for details.
Meanwhile, I’m off to dole out a few bucks in exchange for some dead cabbageworms.