Biocontrol offers natural pest control

Dan Bean is the director of the Colorado Department of Agriculture Insectary./Courier photo by Ruth Heide

MONTE VISTA — Chemicals are not the only option for dealing with noxious weeds. Farmers might want to bring in the bugs instead.

Agricultural Conference & Trade Show speaker Dan Bean, director of the Colorado Department of Agriculture Insectary in Palisade, shared biological pest control options during his Tuesday talk at the conference in Monte Vista.

The insectary’s work began in the 1940’s with the oriental fruit moth problem in peach orchards in the Palisade area. Biocontrol agents used a wasp to take out the oriental fruit moths. Since then the agents at the insectary have developed numerous biological options to control noxious weeds such as Russian Knapweed, which is a problem in the San Luis Valley.

Biocontrol is using living organisms to control pests, Bean explained. These might include insects, mites, flies, wasps or pathogens like rust.

Bean said farmers should consider these biocontrol agents because they are safe, effective and inexpensive. People using the insectary’s services either pay nothing or minimal fees, he said.

“It’s a critical component when managing weeds or pests,” Bean said. “It’s also sustainable.”

The living organism is self propagating, so once a control agent is introduced, it will continue attacking its designated target. As a living organism it can adapt and evolve in ways a chemical cannot, Bean added.

Using biocontrol can be critical in reducing the use of pesticides, Bean said.

In addressing how safe biocontrol is, Bean said everything the insectary uses has been tested at least 10 years, because it takes that long for the testing and regulatory process to get to the point of a biocontrol agent being approved for release.

The insectary only uses specific species not general varieties that would hit other plants, Bean added.

He referred to the beetles used to attack tamarisk, an invasive plant that sucks the water out of an area. He said they do not destroy willows or cottonwoods but seek only the tamarisk. “They are tuned in to one plant. They don’t do anything else.”

Specific beetles have been introduced to attack the noxious weed leafy spurge, mites to kill bindweed, rust/fungus to destroy the noxious weed Canada Thistle and parasitic wasps to control the Emerald Ash Borer, which can move through a forest and wipe it out.

When asked if there was some biocontrol agent that could be used against the pine beetles that have devastated forests in Colorado, Bean said the insectary was not doing anything with the pine beetle because they are native.

“I think we should look into it, see if there’s any way we can help,” he said.

“They do have natural enemies, but they have outrun them,” he added.

In the San Luis Valley the noxious weed Russian Knapweed is a problem. Specific wasps and gall midges (flies) have been successful in destroying Russian Knapweed, Bean said. Testing began with these biocontrol agents in the 1990’s and they were finally permitted to be used in 2008/2009. With four to five generations a year, the gall midge is prolific and easy to raise and introduce, Bean said.

In 2018, 9,000 galls were released including in the San Luis Valley, he said. “It’s a good active program going on here. They have survived over the winter here.”

The wasps used to fight Russian Knapweed only produce one generation per year but lay their eggs and gall up in the plant and the larvae spend the entire summer and winter there and come out in the spring, Bean explained.

Anyone wishing to learn more about biological pest control agents that are available may contact bean at [email protected], 970-464-7916 or through the Palisade Insectary web site.

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