Weed-eating Beetle to the Rescue

“We have to reduce pesticide use, and there is a way!
It’s called biocontrol.”
-Arne Witt, Invasive Species Coordinator for CABI

Last week, the IPM Innovation Lab co-hosted a workshop in Ethiopia on the management of the viciously invasive weed, Parthenium hysterophorus, which has much of Ethiopian farmland in a stranglehold.

This weed, a native of Mexico and Central America, stowed away on shipments of grain that were part of food aid to Ethiopia in the 1970s. With no native enemies in Africa, it has spread widely and has now become a huge problem—the weed causes skin rashes and asthma, and taints the milk of cows that eat it. In Amharic, it is called “faramsissa,” meaning, “sign your land away.”

Researchers and scientists from the IPM IL and its partner institutions determined that the most cost-effective, environmentally friendly way to control the weed would be to release a biological control agent – or “bioagent.” In this case, bioagent refers to a pea-sized beetle called Zygogramma bicolorata that feeds only on Parthenium.

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When people first hear about biological control as a method to manage invasive species, they are often skeptical. Introducing insects to a new environment sounds like a recipe for disaster. What they don’t understand is that these insects are rigorously tested. Their appetites and breeding habits are scrutinized under quarantine. Bioagents are deployed only when scientists are confident that the insects eat and breed on the targeted invasive species alone.

The  Zygogramma beetle is specific to Parthenium, and after a laborious three-year process involving many agencies and much red tape, it was finally approved for release.

After authorities gave the green light, researchers collaborated with farmers, the local ag bureau, and extension agents to build a breeding facility and increase the number of bioagents.

And last week, the IPM Innovation Lab team joined a group of about 30 scientists in Wollenchiti, Ethiopia, to participate in the great beetle release. The group was trundled around Adama, Ethiopia, from Parthenium patch to Parthenium patch, dumping out containers full of unsuspecting beetles. It was no elaborate dove ceremony, but the significance of the release should not be underestimated; if the bioagents establish in Ethiopia, they will ease the burden on smallholder farmers, reduce the amount of pesticide being used, and contribute to food security in this region.


Weed-eating Beetle to the Rescue

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