Crawlies with Cri: Asparagus beetle

Asparagus beetle (Crioceris asparagi)
(Photo by Christy Solo for the Illinois Valley News)

Asparagus beetle (Crioceris asparagi)

This week’s crawly is a pretty critter you’ll most likely never see, but nothing is impossible. Meet the asparagus beetle (Crioceris asparagi).
As the name implies, these beetles dine on asparagus when they are larvae. However, despite California and Washington being two of the four states that produce the most asparagus in the United States, asparagus beetle sightings are few.
In fact, there are only three recorded sightings of them in Oregon. There are two records each in Washington and California.
Asparagus beetles are known as an “adventive” species in the US. This means they’ve been introduced but are not fully naturalized. Most sightings of them are in the northeastern US.
They are native to Europe and northern Asia but have been in North America since 1899. With such a long history in the Americas and so few finding their way west, you can rest easy that they won’t be chowing down on your garden asparagus any time soon.
I don’t know about you, but I, at the very least, admire asparagus beetles for their good taste! Who doesn’t love asparagus? (see Recipe Corner on pg. 8 if that got you craving!)
Asparagus beetles are also quite pretty. Even at just over one-quarter of an inch in size, their distinctive colors are easy to see. They are members of the leaf beetle family (Chrysomelidae), a family known for its bitty, bright, boldly patterned members.
There is quite a bit of variation in the patterns found on asparagus beetles. Our pictured beetle sports a lot of white, but many have a perfectly even black and white checkerboard pattern on their elytra (hardened wing covers). Some have four white stripes, some two stripes and two squares. All are completely dependent on asparagus.
Asparagus beetles can be found (when they can be found) year-round. In colder months, they’ll hibernate in leaf litter around their host plant. They become active in spring when the weather warms and asparagi begin to grow.
Adults will chew on new leaf shoots and stems. Around June they’ll begin laying eggs. The eggs look like very small footballs and are glued to leaves and stems in neat little rows by the females.
Unlike many adult beetles, adult asparagus beetles stick around while their young grow. When adults and young share the same food plant, they stick together.
After about a month of feeding, the larvae scoot down the asparagus stems and burrow into the soil. There they’ll weave silken cocoons and spend the next two to three weeks morphing into their final adult form.
In warm climates, asparagus beetles will go through two cycles from March through September, then the fall adults go into hibernation. In cooler places, like the northeast in the US, they’ll only have one brood per year.
In areas where asparagus beetles are found in large enough numbers to be considered crop pests, they are successfully controlled with Tetrastichus coeruleus chalcid wasps who parasitize the asparagus beetles’ eggs.