“If you were an aphid on a head of lettuce, a hoverfly larva would be a nightmare. They are voracious eaters of aphids. One larva per plant will control the aphids.”
That's what organic researcher Eric Brennan of the Agricultural Research Service (ARS), U.S. Department of Agriculture, told reporter Jim Robbins in a recently published New York Times article.
Headlined "Farmers Find Organic Arsenal to Wage Wars on Pests," the news story drew attention to why natural enemies are "key to the organic approach."
Brennan is based in Salinas Valley, known as "The Salad Bowl of America." It's reportedly where 80 percent of Americans get their greens.
And it's where the lettuce aphid gets its lettuce.
To help resolve the problem, organic farmers are planting alyssum in their lettuce beds. Hover flies "live in the alyssum and need a source of aphids to feed their young, so they lay their eggs in the lettuce," Robbins wrote. "When they hatch, the larvae start preying on the aphids."
Could be that the "salad days" are over for the aphids--thanks to Brennan, alyssum and hover flies.
Aren't syrphid flies grand?
Syrphid flies, aka hover flies or flower flies (family Syrphidae), are especially grand in a Calandrinia grandiflora, aka rock purslane.
Often mistaken for honey bees, these insects hover over flowers, wings spinning like helicopters, and then dart inside a blossom to feed on pollen and nectar.
We spotted a brightly colored syrphid on a rock purslane in our garden last Sunday. It appeared in no hurry to leave its host.
Is it true that this colorful fly is in the same order (Diptera) as the common housefly? It is.
Hover flies are found everywhere in the world except Antarctica. For a look at some of the species, check out BugGuide.Net. The site contributors are self-described naturalists "who enjoy learning about and sharing our observations of insects, spiders, and other related creatures."
Another great source is entomologist Robert Bugg's 25-page booklet, "Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops," published in May 2008 by the University of California, Division of Agriculture and Natural Resources (UC ANR). You can download it for free by accessing this page.
Have you seen the little syrphid flies, aka flower flies and hover flies, hovering around the early spring blossoms?
Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the UC Davis Department of Entomology, said these syrphids (below) are probably from the genus Toxomerus. The family is Syrphidae (flower flies).
The larvae of these insects are good to have in your garden--they eat aphids, thrips and small caterpillars. The adults feed on nectar and pollen.
The syrphids fly so fast that you almost need a motor drive to capture them in flight. Plus, they seem especially skittish this time of year. Shadow them with your body or camera and they're gone in a flash.To learn more about flower flies, a good read is Robert Buggs' 25-page booklet, "Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops," published in May 2008 by the University of California, Division of Agriculture and Natural Resources (UC ANR). You can download it for free by accessing this page.
It's illustrated with photos that will help you recognize many of the syrphids.
A trip today to Marin County, with a side trip to the Marshall Post Office in Marshall, yielded a triple bonus.
A bumble bee, a honey bee, and a syrphid or flower fly all were nectaring flowers on the post office grounds, located right across from a restaurant and marina we were visiting.
They must have known it was National Pollinator Week. They were all sharing the same space.
"Insect pollinators, including honey bees, pollinate products amounting to $20 billion annually in the United States alone," say officials with the National Pollinator Partnership.
About 80 percent of the world's depend on pollination. And almost all pollinators are insects.
What better way to close out National Pollinator Week, which ends June 28, with photos of three pollinators? These images were captured right outside the tiny postage-sized Marshall Post Office.
National Pollinator Week certainly has our stamp of approval.
Signed, sealed and delivered.
If you see a caterpillar near a cluster of aphids, don't squash it. It could very well be the larva of a syrphid or hover fly (family Syrphidae) and it's eating aphids.
What do they look like? I happened to capture an image of a tiny syrphid larva on a rose leaf, and sure enough, it was eating aphids.
Community ecologist Louie Yang, who joined the UC Davis Department of Entomology faculty last year, has also photographed syrphid larvae. He recognized this one right away.
If you want to learn more about syrphid flies, be sure to read Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops, Publication 8285 (May 2008), UC Division of Agriculture and Natural Resources. It's primarily the work of UC Davis entomologist Robert Bugg; with expertise offered by Ramy Colfer, chief organic agricultural researcher, Earthbound Farms, Salinas; William Chaney, farm advisor, UC Cooperative Extension (UCCE) Monterey County; Hugh Smith, farm advisior, UCCE Santa Barbara and San Luis Obispo counties; and James Cannon, UC Davis computer resource specialist.
In the publicaiton overivew, Bugg writes that "Flower fly development involves complete metamorphosis, including egg, three larval stages, puparium, and adult. Adults of many flower fly species resemble stinging bees and wasps. This phenomenon is called Batesian mimicry, indicating that palatable organisms resemble or 'mimic' unpalatable models. Worldwide, there are many aphidophagous syrphid speices."
"Adult hover flies require honeydew or nectar and pollen to ensure reproduction, whereas larvae usually require aphid feeding to complete thir development."
Below, you'll see a syrphid larva doing what it does best: eating aphids.