Western spotted cucumber beetles know how to hit the spot.
Make that "multiple spots."
These beetles, Diabrotica undecimpunctata, are agricultural pests that feed on roots, seedlings, flowers and foliage. And they can transmit diseases.
But have you ever seen feed on flower petals when you're wandering around in your garden?
"Cucumber, flea, and leaf beetles are pests of many flowers, including dahlia, lily, and sunflower," according to the UC Statewide Integrated Pest Management (UC IPM) Program. "Adult cucumber beetles are shiny with black heads, long antennae, and about 0.25 inch long. Larvae are whitish and slender with three pairs of short legs; the head and tip of the abdomen are darker. Adults may be striped or spotted, depending upon species. Flea beetles are small, shiny beetles with black legs enlarged for jumping. Other leaf beetle adults are long, oval, blunt, and have threadlike antennae. The blue milkweed beetle adult is metallic green-blue."
"Adult beetles chew holes in leaves; some species also consume shoots and blossoms. Larvae of cucumber beetles and flea beetles chew roots, which can stunt crops. Seedlings can be destroyed within a few days. Older plants can tolerate relatively large numbers."
In our pollinator garden, spotted cucumber beetles are extraordinarily fond of our Mexican sunflowers, Tithonia rotundifola. We've seen them chew multiple holes in the petals.
Caught in the act!
Let's hear it for biocontrol.
You've seen lady beetles, aka ladybugs, preying on aphids.
But have you seen an assassin bug attack a spotted cucumber beetle?
How about a crab spider munching on a stink bug?
All biocontrol, part of integrated pest management (IPM).
If you access the University of California Statewide Integrated Pest Management Program (UC IPM) website or more specifically, this page, you'll learn that "Integrated pest management, or IPM, is a process you can use to solve pest problems while minimizing risks to people and the environment. IPM can be used to manage all kinds of pests anywhere–in urban, agricultural, and wildland or natural areas."
Or, UC IPM's more in-depth definition:
"IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment."
Think of biocontrol as beneficial: "Biological control is the beneficial action of predators, parasites, pathogens, and competitors in controlling pests and their damage. Biological control provided by these living organisms (collectively called "natural enemies") is especially important for reducing the numbers of pest insects and mites, but biological control agents can also contribute to the control of weed, pathogen, nematode or vertebrate pests."--UC IPM
Yesterday we witnessed an incredible case of biocontrol in action.
At Bodega Bay's Doran Regional Park, Sonoma County, we spotted a great blue heron stepping stealthily through a thatch of ice plant in the Jetty campground. It was 6:30 in the morning. As campers slept in their recreational vehicles a few feet away, the great blue heron just kept stepping silently through the ice plant. One step. Another step. And another.
And then it happened. Its long sharp beak speared a rodent. Yes, they eat rodents. It crunched the body from head to toe, breaking the bones, and then swallowed it whole.
Not a pretty picture, but a simple case of biocontrol, compliments of a hungry heron.
Down on the farm...the Loma Vista Farm....
When the Loma Vista Farm--part of the Vallejo City Unified School District--recently hosted its annual Spring Festival, scores of folks came to see the animals, buy a plant or two, and participate in the many activities.
But if you looked closely, you could see that the farm, located at 150 Rainier,Vallejo, is also a pollinator habitat and home to many insects.
Lady beetles, aka lady bugs, munched on aphids in the garden (the garden feeds Vallejo school children as well). Those pesky spotted cucumber beetles also showed up. We spotted a beneficial insect (lady beetle) and a pest (spotted cucumber beetle) sharing a leaf.
A Western tiger swallowtail fluttered down to the aptly named butterfly bush for a sip of nectar. The caterpillar of an anise swallowtail dined on the leaves of its host plant, anise, also called fennel. (It smells like licorice to us!)
All the while, a colony of yellow-faced bumble bees, Bombus vosnesenskii, went about their bees-ness, entering and exiting a hole in the ground in a pattern that would alarm human air controllers. They zigged, zagged and then bumbled through with huge pollen loads, sometimes nearly colliding.
The Loma Vista Farm is also the habitat of "Farm Keeper" Rita LeRoy, who has worked for the Vallejo school district for 25 years. She teaches students about nature and nutrition through hands-on farm lessons involving cooking, gardening, insect appreciation, and animal care. She is an avid entomological enthusiast, an insect photographer, and a member of the Pollinator Posse.
Founded in 1974, the Loma Vista Farm is described on its website as a 5-acre outdoor classroom that provides hands-on educational activities involving plants and animals for children of all ages and abilities. "We seek to increase students' knowledge of nature and nutrition while enhancing academic learning, ecoliteracy, and psychosocial development."
The farm offers field trips, after-school opportunities through 4-H, community service and volunteer opportunities, garden-based workshops for adults, and job training for college students, developmentally disabled young adults, and disadvantaged youth.
It's open to the public Monday through Friday from 9 a.m. to 2:30 p.m. during the school year.
It's open to insects year around!
How many times have you heard that?
Often it is not the beneficial lady beetle--commonly referred to as a ladybug--but that dratted pest, the spotted cucumber beetle.
In a case last week, it was the dratted spotted cucumber beetle, or more specifically, the western spotted cucumber beetle, Diabrotica undecimpunctata undecimpunctata, being "diabotical" on an Iceland poppy.
Lady beetles, the good guys and girls, can be many other colors besides red with black spots. They can also be with or without spots or stripes. They're the blue ribbon winners when it comes to devouring aphids and other soft-bodied insects.
The spotted cucumber beetle, however, is a pest of many of our agricultural crops, including the cucurbits family, Cucurbitaceae, which includes cucumbers, squash and zucchini. You'll also find these little diabolical munchkins just about everywhere.
"Western striped cucumber beetle larvae feed exclusively on cucurbit roots, whereas western spotted cucumber beetle larvae feed on a wide variety of plants including grasses, corn, legumes, and cucurbits," according to an entry in the UC Statewide Integrated Pest Management (UC IPM) Program's Pest Management Guidelines.
So, the next time you're slicing a melon, remember what UC IPM says: "Cucumber beetles are serious pests of smooth-skinned cucurbits, especially melon varieties such as honeydew, crenshaw, and casaba. While the adults prefer tender, succulent portions of plants, including the flowers and leaves, which they may destroy with their feeding, it is the damage to the surface of the melon that reduces marketable yield. When temperatures are high, adults especially feed on the undersides of young melons, scarring them. After the skin hardens, melons are much less subject to attack. Scarring in the crown of the plant is also typical of adult damage. Feeding on stems of young plants, followed by sustained winds, may result in severe stand reductions making replanting necessary. In some situations, larvae may cause serious injury by feeding on roots, and young plants can be killed. Cucumber beetles also spread squash mosaic virus."
A cute little ladybug? No.
Pretty? Well, it is quite photogenic.
Perhaps it was searching for a thistle.
The Mylitta Crescent butterfly (Physiodes mylitta) did not find the thistle—at least in our bee garden.
What it did find were the leaves of a tower of jewels (Echium wildpretii) where it sunned itself before fluttering off to parts unknown.
This butterfly breeds on thistles, says noted butterfly expert Art Shapiro, professor of evolution and ecology at the University of California, Davis. He monitors the populations of Central California butterflies on his website.
"With the naturalization of weedy European species of Cirsium, Carduus and Silybum, it (the Mylitta Crescent) is now found in all kinds of disturbed (including urban) habitats," he says on this website.
Perhaps the next time we see the invasive bull thistle, Cirsium vulgare, growing in a field or alongside a road, it will be occupied by not only a spotted cucumber beetle (a pest) but a Mylitta Crescent.