Palisade Insectary: Safeguarding The Taste + Landscape Of Western Colorado

Renowned for its mouthwatering flavor, the Palisade peach has a fan base that stretches far beyond its namesake town. As this year’s harvest wraps up, it’s time to meet an unsung hero behind the success of this signature Western Colorado crop: the Palisade Insectary.

Home to the state’s biocontrol program and an intrepid team of entomologists, the Insectary once helped save the Palisade peach from destruction. Today, it plays a key role in the survival of the fruit — and the taming of invasive weeds all over Colorado.

Photos courtesy of Palisade Insectary

FIGHTING A PEST WITH ITS NATURAL PREDATOR

In 1945, Palisade fruit orchards came under attack by a voracious moth that had been introduced by rail car the year before. Now known as the peach moth, this pest attacks trees from the inside out, stunting growth and destroying fruit. It’s especially hard on stone fruit. Bite into a Palisade peach in 1945, and you were likely to find a bruised, brown, inedible interior — courtesy of the peach moth. The entire Grand Valley fruit industry was at risk.

Pesticides didn’t faze the peach moth, which bores into branches and beneath fruit skin, evading spray. That’s when entomologists stepped in. A government-funded team set up shop in a small house at First and Main in Palisade where they got to work on Colorado’s very first biocontrol program. Their aim: control the peach moth with its natural enemy — a stingless wasp called the Macrocentrus ancylivorus.

Known as Mac, this little wasp — just larger than a mosquito — has succeeded where chemicals didn’t. After breeding the insect indoors, Palisade Insectary entomologists released Mac into orchards in spring 1946. As expected, the wasp sought out the peach moth caterpillar, where it laid its eggs. When the Mac eggs hatched, well…. “It’s like a scene from the movie Alien,” says Insectary manager Dan Bean of the peach moths’ grisly end.

“Mac became the kind of hero wasp we want to have around,” Bean wrote on historycolorado. org, “saving delicious Colorado peach crops from [peach moth] decimation ever since. And thanks to Mac, the Palisade Insectary was born.”

ONLY IN PALISADE: POTATOES, WASPS AND PROVOKING CALIFORNIA ENVY

Peach moth

“It’s a miraculous program,” says fifth-generation orchardist Dennis Clark of Clark Family Orchards. “We truly don’t have an OFM [peach moth] problem to speak of.” Between May and August each year, he and about 80 other growers receive free paper bags of Mac pupae to hang in peach trees, spaced at about one per acre. Clark sprays his family’s 130 acres for aphids and other insects, but Mac reduces the overall volume of pesticide he applies.

Because Mac doesn’t overwinter in Palisade, the Insectary continues to raise and distribute some 1.5 million wasps annually. The method hasn’t changed much since 1945, with entomologists drilling holes in potato tubers that will host the next generation of Mac. The adult wasps fly free in the friendly confines of the Insectary, attracted to a backlit window. Then, they’re sucked up with a vacuum hose and transferred to the potatoes, where they lay their eggs.

California peach growers would love to have a Mac program of their own, says Bean. But, Palisade has the only one in the country. In California, commercial peach orchards cover 30 times more acreage than their Palisade counterparts — making the Golden State operation too big to benefit from this biocontrol. With just 2,000 acres of Palisade peaches in cultivation, Mac manages to protect Western Colorado’s boutique, high-yield fruit.

BEYOND THE PEACH ORCHARDS

Bindweed

The Palisade Insectary — which predates the U.S. Department of Agriculture — has grown its reach enormously since its founding. Today, it offers about 20 biocontrols to safely control noxious and invasive species that range from tamarisk to Russian knapweed to puncturevine. Its most-requested bio-weapon? A gall mite that’s the natural enemy of the field bindweed.

Puncturevine

In recognition of its expertise, the Palisade team is also on the front lines of the fight against an up-and-coming species: the yellow star thistle. Already spreading across 12 million acres in California, this invasive plant is considered one of the state’s most serious rangeland weeds. Bean and his team are raising weevils in hopes of halting the thistle’s progress in Colorado.

INTO THE FUTURE: GENETIC MATCHING

But are those weevils — collected from a certain spot in Greece — the exact genetic match to combat the type of yellow star thistle that threatens the Centennial State? Maybe the thistle came from a completely different patch of Greek soil — or another country entirely. “The better the match between the weevil and the thistle,” explains Bean, “the more likely the success.” In biocontrol, one size definitely doesn’t fit all.

Bean is eager to incorporate more modern science into the Insectary’s work with genetic sequencing of insects and plants. “Think of it as 23andMe for bugs,” he says. “New genetic tools will allow us to look more closely and make the best fit.”

Also on Bean’s radar: closer partnerships with Colorado Mesa University professors and computer modeling of habitat requirements.

REQUEST YOUR OWN BIOCONTROL BUG

Weed-fighting biocontrol bugs aren’t just for commercial operations or large landowners. Anyone in Colorado can request a biocontrol through the Insectary. Concerned about safety? Before it can be released, every new species of insect undergoes at least 10 years of research and testing. Because of these precautions, the U.S. biocontrol program has a sterling record with zero “oops” incidents affecting the wrong plants.

In Western Colorado, September is the Insectary’s preferred time to combat puncturevine — aka the cyclist’s roadside enemy the goat head. Canada thistle is also on the firing line through October. Costs for biocontrols to fight these and other invasive weeds range from $30-$50. The Palisade Insectary also offers tours where you can meet entomologists, learn more about their work and maybe even see the savior of the Palisade peach industry, the Mac wasp.

To request biocontrol bugs or to schedule a tour, contact the Insectary at 970.464.7916 or visit palisadeinsectary.org.

Originally published in the Fall 2023 issue of Spoke+Blossom.