I was hanging out my washing the other day, and when I finished, I found a little visitor had jumped into the empty washing basket. I’d have probably missed him otherwise, but as he was essentially trapped, I whipped out my phone and took a picture of the little critter. You can see his picture below, and by my guess, he had blown or fallen down from the gigantic LabLab Bean I have growing over the laundry.
This little guy is a Green Vegetable Bug (Nazara viridula) and is a common pest of pulses. This includes beans, peas, lentils, soybeans and pretty much everything vaguely related to beans except for Chickpeas (Cicer arietinum). These guys are actual bugs, which if you were an entomologist would mean something useful in describing their life cycle. Let’s just say for now, all bugs are insects, but not all insects are bugs. GVBs hatch from yellowish egg clusters, and grow in stages, called instars, until they are full sized adults. The young look more or less the same as the grown-ups, except for the colouration.
The thing that really sucks about these guys is they really do suck. They use their piercing mouthparts to poke into almost developed beans in their pods, and suck all the goodness out. That means less for us to eat, or at the very least, sad looking, mis-shapen beans or peas. In really bad infestations, there may be up to 20 bugs per square metre, which means a lot of damaged beans. They can also attack flowers and early pods, too, reducing yields even further, and may suck sap from other plants including corn, sunflowers and tomatoes. They are also becoming a problem in commercial cotton crops, and with the the amount of pesticides already used on that crop, they may be developing resistance to chemical sprays. They don’t like being disturbed, and will actually spray a stinky substance that can stain your skin or clothing. Little skunks.
They can be controlled with chemical sprays, though they can be pretty toxic. They are relatively easy to catch and kill by hand, if you can see them first, but wear gloves to avoid being stinkified. There are two parasitic wasps that will help keep their numbers down, one which destroys their eggs (Trissolcus basalis) and another which attacks the adult bugs (Trichopoda giacomellii). You can search for suppliers on the internet, and most companies will mail the appropriate predator along with instructions. The thing to remember is to avoid other pesticides that could harm the good guys once they are released.
I am sure you will see them around once you start looking, but possibly not so much in the colder months. I think mine was looking for somewhere warm to hide.