Elm Leaf Beetles are an invasive species in the Denver Metro area, as well as the rest of the lower 48 states in America.
In case you didn’t know, there are over twelve thousand elm trees in Denver. They make up eighteen percent of Denver’s canopy cover in our urban forest ecosystem. They’re a well studied pest in forestry, because they’ve been a known invasive species for a really long time — and seriously damage elm trees.
Both adult beetles and their larvae eat elm leaves on the surface. The green-and-yellow adults lay eggs on the leaves. When the babies are born, they eat the leaves, leaving them looking lacy and dead. Loss of foliage from the trees is both an aesthetic and functional setback, as it reduces shade cover, and can increase the tree’s susceptibility to diseases, like Dutch Elm Disease.
It’s hard to prevent an infestation, because of how widespread the pest is. One cure-all for keeping any tree healthy is keeping the soil at the base of the tree saturated with water, as long as weather will allow it.
There are few natural (or ecologically preexisting) enemies of Elm Leaf Beetle populations. Certain small parasitic wasps and breeds of fungi can reduce population sizes at the pupal stage. However, these species aren’t nearly as widespread as Elm Leaf Beetles are.
If your trees are experiencing an infestation you’ll want to schedule a consultation with a certified arborist from Colorado Trees.
By treating an infestation, you’re reducing the beetle population, and ensuring improved tree health for the following season. For instance, this year (2020), Colorado has seen a huge impact from elm leaf beetles.
Elm Leaf Beetles are known to seek shelter inside homes and other buildings for harsher winter months, and more often than not, they don’t make it back outside. That’s just icky!
It’s important to treat an Elm Leaf Beetle infestation sooner, rather than later. Just like you’d rather see a doctor with the sniffles and a headache, rather than in a more dire situation. Trees can be treated early on!