Tag Archives: invasive

Puncture vines are awful

I thought I’d write a post about puncture vines (Tribulus terrestris) in case anyone out there is wondering what to do about them. By way of introduction, below is a photograph of the bottom of one of my shoes after a short run in Madras, Oregon. Those are puncture vine burrs (91 of them, counting both shoes), all picked up during the approximately 10 seconds when I ran through a segment of Cowden Park.

The spined fruit functions like a caltrop (or tribulus), a barbed, stationary weapon that can pierce footwear. The spines can lodge in dog paws and puncture bike tires. Below is a close-up.

The plant itself looks harmless, but if you see it on your property you should kill it on sight. It can produce hundreds of seeds per year.

In Oregon, you should report an infestation to the Oregon Invasive Species Online Hotline. You can also search the associated database to see where the weed has already been reported and whether state or local officials came and dealt with it. And if you live in Madras, Oregon, they have a website devoted to the weed, and apparently can fine residents $500 (per day) for allowing the plant to grow unchecked. If you live in a town that has the species but that doesn’t have a group working to fight it, start one.

How to control

According to message boards on the topic, it takes about three years of killing puncture vines to achieve success, so stick with it even if it seems futile. When you walk around your property, always take a tool that can pop the plant out along with most of the tap root (they come out very easily). For weeds like that I really like to use a long-handled puller, the kind with two angled tines at the tip. I also have a smaller version.

In addition to getting rid of the plants, you might also want to get rid of as many seeds as possible. For that, you might invest in a contraption called the Goathead Roller ($295). Per photographs online, small kids can easily push it around. More extensive options for larger properties can be found at stickerburrroller.com. A cheaper option is to attach pool noodles at the end of a paint-roller arm. Or attach the noodle to a chair frame (see on YouTube). For small areas some people have good luck laying down a cheap carpet and then walking around on it, then throwing it away. You can also suck them up with a cordless vacuum (YouTube).

If you live in Arizona, California, Nevada, New Mexico, Texas, or Utah, you might try to procure some puncture vine seed weevils (Microlarinus lareynii) or puncture vine stem weevils (Microlarinus lypriformis), species that were introduced from abroad for biocontrol. Arbico used to sell them but apparently no longer, so interested parties should contact their respective state department of agriculture to find a source.

My 2 cents

This plant is a master at using shoes to disperse to new areas, so I think more parks with infestations should install benches with signs that say, “Please take a minute to de-burr your shoes before leaving so that puncture vines don’t spread.” And there should be two pairs of pliers attached to each end of the bench with cables, just like those pens at the bank.

Houdini fly alert for owners of bee hotels

If you have an insect hotel, you should check your mason bee nests for Houdini flies (Cacoxenus indagator) before the season starts. These non-native flies consume the pollen inside mason bee nests, causing the bee larvae to starve to death. They are very easy to get rid if you have nesting tubes that can be taken apart.

Killing them at the larval stage is easy. Just unwrap your nesting tubes during the winter and squish the larvae (below) before they mature into adults. If you’re not into squishing things, submerge them in alcohol or soapy water before discarding. Or freeze them (just don’t forget about them in case spouse would freak out).

Houdini fly larvae

I had a half-dozen or so cells infested with the flies, so killing them removed approximately 100 individuals (below) from my local population. That won’t eliminate them from my yard but at least my hotel is not part of the problem.

Houdini fly larvae

Here are photographs of the adult. They look like common fruit flies but are darker and considerably less skittish when you approach them — they are so chill you can often squish them with a finger (do that if you can). You’ll notice them lurking around a bee hotel waiting for female mason bees to leave their nesting tube unguarded, then they’ll slip inside and leave a load of eggs.

If you find Houdini flies at your hotel, please upload a photograph to iNaturalist so we can track their spread.

Below are mason bee cocoons, for comparison. You can clean off the frass and mud, wash them, then store outside in a way that protects them from birds and moisture. For details on all how to do that, see this page. If you store them in an unheated garage in a container, check them at least every day so that you can release them.

Mason bee pupae