The elm leaf beetles and their larvae don't want to hold your hand--unless perhaps you're holding a elm leaf that they can eat.
A recent walk down the 200 block of Buck Avenue, Vacaville, California, revealed the damage this pest does. The stately canopied elms don't look so stately, what with the dry skeletonized leaves, the browning and the dieback.
And if you look closer, you'll see the leaves--the feeding site--dropping prematurely, and beetles and their larvae falling with them.
Infestations of these beetles can defoliate large elm trees, according to the UC Integrated Statewide Management Program's Pest Note on this pest, Xanthogaleruca (=Pyrrhalta) luteola.
Have you ever seen them? They're about 1/4 inch long, yellow to olive-green with a black stripe on each side and four black spots near the head. They are an invasive species from southern Europe, introduced here in the 1800s, and considered the most serious elm defoliator in the United States.
"Females lay yellowish eggs in double rows of about 5 to 25 on the underside of leaves," according to UC IPM. "Eggs become grayish before hatching. Larvae resemble caterpillars and are black when newly hatched and shortly after molting (shedding the old skin). After feeding, larvae become yellowish to green with rows of tiny dark tubercles (projections). Third-instar larvae grow up to 1/3 inch long and have dense rows of dark tubercles down their sides that resemble two black stripes. Pupae are orange to bright yellow."
We observed some natural enemies on site: lady beetles, aka ladybugs, and their larvae munching on the larvae of the elm leaf beetles. Yes, beetle larvae eating beetle larvae. Lady beetles and their larvae target soft-bodied insects, and not just aphids.
UC IPM says:
"The elm leaf beetle develops through four life stages: egg, larva, pupa, and adult. Adults commonly overwinter in bark crevices and woodpiles or in buildings. In spring they fly to elm foliage and chew leaves, and females lay eggs. Eggs hatch into larvae that develop through three instars (growth stages) over a period of several weeks while chewing on foliage and then crawl down the tree trunk. Mature larvae become curled and inactive (a stage referred to as prepupae), then pupate, sometimes in large numbers, around the tree base. After about 10 days as pupae, adults emerge and fly to the canopy to feed and, during spring and summer, lay eggs. The elm leaf beetle has at least one generation a year in northern California and two to three generations in central and southern California."
Elm trees with massive defoliation can weaken the tree and pave the way for diseases and damage from other pests.
If you have elm trees, especially European elm species, and you have these little buggers all over them, you might want to access the UC IPM Pest Notes to see how to manage them.
These beetles mean business./span>
It's a magical moment.
First an egg, then a caterpillar, then a chrysalis, and then a butterfly, Danaus plexippus.
We took some images of a monarch eclosing back on Sept. 10, 2016. It was late in the season. While other monarchs were migrating to coastal California, some were fluttering into our yard in Vacaville, Calif., nectaring on blossoms, mating, and laying eggs on milkweed, their host plant.
The caterpillar, from the first instar to the fifth instar, munches the milkweed like there's no tomorrow (maybe there isn't?), and then forms an emerald green chrysalis, dotted with gold that's reminiscent of royalty. When it turns transparent, you can see the familiar black and orange wings, a promise of what's to come.
It takes about two weeks for an adult butterfly to emerge from its chrysalis and then it slides out--swoosh!--and hangs upside down, pumping fluids into its expanding wings. When the wings dry, off it goes. Sometimes it soars high into the sky. Sometimes it just lingers.
If you're a butterfly aficionado, you never get tired of watching that magical moment when a monarch ecloses.
Here's to Independence Day and to America's favorite butterfly, the monarch.
Our hearts are with the victims and what we can do to help.
But we briefly stepped out in the backyard yesterday (Oct. 10) in Vacaville to see a sun and sky we did not recognize. Nearby, the brightly colored orange Gulf Fritillary butterlifes (Agraulis vanillae) continued their life cycle on the passionflower vine (Passiflora), their host plant. So unreal to see:
- An egg on the tendrils.
- A caterpillar munching leaves.
- A newly eclosed Gulf Fritillary clinging to its pupal case.
- An adult spreading its wings in the eerie light, ready to start the process all over again.
Mother Nature is not kind. Neither is Father Time./span>
They didn't get the memo.
Summer is over. Fall is underway. Winter is coming (Dec. 21).
But the Gulf Fritillaries (Agraulis vanillae) are still laying eggs on the passionflower vine here in Vacaville, Calif. The eggs are hatching. The caterpillars are eating. The 'cats are pupating. And the adults are eclosing from the chrysalids.
And then the cycle of life begins all over again: from egg to caterpillar to chrysalis to adult.
Actually, we've seen Gulf Frits here year around--even photographed them laying eggs on Christmas Day. Gulf Frits don't go through diapause here. They mate year around.
Of course, the survival rate is low. An estimated 95 percent of all butterflies don't make it from egg to adult, scientists say.
We've seen why. Spiders, praying mantids, yellowjackets, European paper wasps, birds, diseases, and such parasitoids as tachinid flies and wasps that lay their eggs in the caterpillars or bore into the chrysalids.
If you look closely, you can sometimes see the parasitoid evidence (hole), such as the one below. Art Shapiro, distinguished professor of evolution and ecology and an expert on butterflies, says that judging by the size of this hole, it was a large parasitoid--probably a big tachinid fly or an ichneumonid (wasp).
Just part of the cycle of life...
Let's celebrate the Gulf Fritillary (Agraulis vanillae).
If you have a passionflower vine (Passiflora) in your yard, you've probably seen these spectacular orangish-reddish butterflies with silver-spangled underwings fluttering around--the males patrolling for females, the mating, the females laying eggs, the caterpillars hatching from the eggs, and the caterpillars munching and crunching until their last instar. Then you'll see them forming chrysalids, and butterflies eclosing.
The unseen world of Gulf Frits. The miraculous unseen world of Gulf Frits. Because it is.
That came to mind the other day when two passersby saw a dozen or so Gulf Frits heading into our yard.
"Look at all the butterflies!" one exclaimed. "I wonder what's attracting them."
"I don't know," the other said. "They must have a butterfly bush, maybe?"
"Oh, that's probably it. A butterfly bush."
Well, what's attracting them is the Passiflora, the host plant of the Gulf Frits. It's a congregation without a church. It's a gathering without a sermon. It's Nature at its finest. The Gulf Frits, aka "passion butterflies," lay their eggs only on the passionflower vine--mostly on the tendrils or leaves. The caterpillars will eat only Passiflora. The adults? They'll nectar on such plants as the butterfly bush, Mexican sunflower and lantana but will stay close to the Passiflora for mating and egg-laying.
If you're lucky, you'll see the entire life cycle--from egg to caterpillar to chrysalis to adult.
If you're really lucky, you'll see the tiny yellow eggs, which are about the size of the period at the end of this sentence. The yellow eggs turn from orange to rust, the color of the caterpillar inside.
The butterfly, found in many parts of the world, is a relatively newcomer to California. It was documented in Southern California, in the San Diego area, in the 1870s, according to butterfly guru Art Shapiro, distinguished professor of evolution and ecology at UC Davis. “It spread through Southern California in urban settings and was first recorded in the Bay Area about 1908. It became a persistent breeding resident in the East and South Bay in the 1950s and has been there since.”
Shapiro says it “apparently bred in the Sacramento area and possibly in Davis in the 1960s, becoming extinct in the early 1970s, then recolonizing again throughout the area since 2000.”
Today I explored the unseen and intricate world of Gulf Frits in our Vacaville (Solano County) backyard, managing to capture a few images. Then the unexpected happened. For the first time in the five years we've been rearing Gulf Frits, one landed on me! Apparently mistaking me for a plant, she touched down on my green t-shirt (which probably carried the scent of the passionflower vine). She was all set to lay an egg until....two males approached. Startled and a bit rattled--hey, I'm laying an egg here, leave me alone!--off she flew.
This time she vanished inside the depths of the passionflower vine.
With any luck, she'll do just fine in this congregation without a church, in this gathering without a sermon. She'll provide another generation that resembles the striking colors of those stained glass windows in a religious sanctuary.