Last year, on a sunny June day, I was giving B&B guests a tour of our garden. They marveled at the blue poppies and paused whenever a boat zipped by.
Suddenly the mom turned and waved her hand toward the house. “What a pretty white butterfly!” she said.
“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 actually cabbage moths,” I said. “They have a bad reputation around here.”
“What’s wrong with them?” her son asked.
“Well, they lay eggs, which hatch into green worms that eat plants like cabbage, radish, and broccoli.”
Her son bolted across the lawn in hot pursuit of a white moth.
Two weeks later, I spotted a velvety green caterpillar on a radish leaf.
Introduced (by accident) in the 1850s, the “cabbage white butterfly” is now common across Europe, North Africa, Asia, Great Britain and most regions of the U.S. Sad news for growers.
The small to medium-sized butterfly is a member of the white-and-yellow family pieridae. Most pieridae butterflies are white, yellow or orange in coloration, often with black spots. The pigments that give the distinct coloring to these butterflies come from waste products in the body. (So if I ate tons of spinach, would I turn green?)
The larvae (caterpillars) cause extensive damage to cabbage-family crops in gardens and commercial fields. It gets worse: I’ve read that a single female of this species can generate a few million generations.
The cabbageworm (Pieris rapae) has a classic, multi-stage life cycle: Adult females emerge in early spring after over-wintering as pupae. They lay about 200 tiny yellow eggs on host plants, usually on the undersides of leaves. How sneaky is that? The eggs hatch in seven to 10 days into young larvae caterpillars.
The larvae are eating machines, feeding heavily for about two weeks. They munch or scrape the surface layer of leaves, which leaves translucent, tissue-like scars. As they grow, they chew large, irregular holes usually beginning on the outside of the leaves. 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 and birds (including chickens and ducks). Installing floating row covers will help prevent adults from laying eggs. And you’ll want to remove leaves (and damaging worms). An ammonia-water spray stops them in their tracks.
Ammonia water deters gooseberry sawflies as well. Read on ...
Gooseberry sawflies have a similar life cycle. Recent comments and posts on Facebook complaining of defoliated currant and gooseberry bushes tell me that sawfly larvae (bright green with black spots) are feeding like crazy. When it’s quiet outside, you can hear them munching. No, really!
And then there are 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.
A spit bug’s reputation is better than that of slugs, cabbageworms or aphids. Oh sure, they cause distorted leaves or stunted plants, but this damage is only temporary and the plants generally outgrow it.
How to cope with spit bugs? Blast them with water or hand pick the nymphs. Otherwise, learn to tolerate them. Note that soap sprays don’t deter them since the froth shields the bugs.
Finally, on a more pleasant note, how to know when to harvest garlic?
Determining when garlic is ready to harvest can be tricky. If you harvest too soon, the cloves will be small, underdeveloped and hard as a rock. If you wait too long, the cloves will begin to separate as the heads dry and they won’t store as well.
By the way, garlic flower stalks, or scapes, are excellent sautéed, grilled or made into a spicy pesto. “Chop and dry them store them in airtight container and use like any other dried herbs,” says Eric Stirrup. “They reconstitute very well in soup stews and sauces.”
Meanwhile, the moths are back again. Now where did that kid go? I’ve got a few dollar bills to give out as rewards ...
Water well, but avoid overhead watering.
Support tall flowers.
Deadhead calendula, pansies and other annuals.
Hill up around potatoes.
Keep cucumbers watered and fed.
Share greens with your neighbors.
Thin radishes, carrots, and beets.
Hoophouse and greenhouse folks: Keep the fans running, pet or tap tomato blossoms and open doors and windows to prevent overheating on sunny days (tomatoes don’t set fruit in extreme heat).