Experts issue warning as dangerous wasp-like insects spread in US — here's what you need to know

Entomologists have warned that European sawflies — invasive bugs that resemble wasps — are taking over pine trees in Washington's Pierce County, perhaps most well-known as the home of Mount Rainier National Park.  

What's happening?

The News Tribune reported that the "wasp-like insects" have been observed laying eggs in pine needles and feeding on pine bushes throughout the county. While the bugs are more of a nuisance than a threat to nature, they can leave huge bare patches on trees, which can detract from the area's natural beauty, according to Todd Murray, an entomologist and director of Washington State University's research center.

Murray explained that the insects are native to Europe and were identified in Washington state in 2008. Luckily, adult sawflies are weak fliers, so their spread throughout the United States and Canada has been relatively slow as they rely on the movement of infested nursery stock, soil, and other materials, per the Government of Canada.

But if you have pine trees in your backyard, the bugs can make them look unsightly as they chow down on the needles. 

Why is the spread of invasive sawflies concerning?

Since the bugs have been spreading in a popular tourist area, it could hurt the county's income from recreation and affect visitors' experience when they visit the park.

Although they're not known to cause significant damage to trees in forests, the sawfly may negatively impact ornamental nurseries and Christmas tree farms, as it spreads easily through plants grown in these settings. Additionally, while pine sawfly larvae don't kill the host trees, continuous loss of pine needles can slow their growth, according to the University of Maine.

When invasive species, such as pine sawflies, spread in a region, they disrupt the balance of forest ecosystems and consume resources that native plants and animals need to thrive. As the sawflies feed on trees, it leaves them more susceptible to attack from other insects and diseases. In some cases, invasive bugs can have severe economic consequences, such as in Hawaiʻi, where coconut rhinoceros beetles and little fire ants have caused thousands of dollars in damage to palm and banana trees, taro, and other crops.

What's being done to keep pine sawflies away from plants?

Murray told The News Tribune that the best way to get rid of sawflies if you spot them on plants is to either knock them off or use insecticides, although the former is better for your health and the environment. However, birds eat pine sawflies, so the easiest solution is probably to let nature do its thing, unless you have a large infestation that requires intervention.

If you want to do your part in protecting native species and conserving the planet, consider starting a native plant lawn that attracts pollinators and saves money on water and lawn care. Native lawns promote biodiversity and create an environment that supports natural predators of sawflies, thereby helping to manage their populations.

Should we be actively working to kill invasive species? Absolutely 💯 It depends on the species 🤔 I don't know 🤷 No — leave nature alone 🙅 Click your choice to see results and speak your mind.

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