The little orange, dotted beetles that are eating my squash plants actually are in the ladybug family. Most beetles in the ladybug family do not eat plants; instead, they eat pests like aphids and whiteflies and are great helpers in our gardens. Mexican bean beetles and squash beetles, which look a lot alike, are exceptions. They are garden pests.
Right now, it is squash beetles in my garden, eating my squash plants.
How to identify squash beetles
The first big clue that they are not Mexican bean beetles is that they are on my zucchini, not on beans. Squash beetles eat plants in the squash family, like zucchini, squashes, and cucumbers. Bean beetles eat plants in the bean family.
Another is that their babies, also called larvae, have dark spines. The spines on Mexican bean beetle larvae are yellow, with dark tips as they get older.
Another clue is the method of eating. Both the babies and adults often gnaw a trench around the patch of leaf they are getting ready to eat. You may notice semicircular lines at the edges of damaged leaves.
One theory about why they do this is that the trenching prevents sap from running into the desired area. The sap may carry nasty chemicals that would interfere with the beetles’ eating.
Organic control of squash beetles
For now, I am hand-picking and smashing the beetles, both adults and larvae. The damage on my plants isn’t severe, and the number of beetles is low. Today, I found and smashed seven adults and one larva.
If the infestation gets bad enough that smashing is insufficient, there are a couple of organic-approved options to try. University of Connecticut agrees that hand-picking can work in small gardens but suggests that products containing spinosad might help if a beetle-damage gets very bad.
Another pest in my garden right now is armyworms
I found armyworms in the garden today, too.
They were on both patches of cleome (spider flowers), and they haven’t left many leaves. When I realized what the pests were, I removed all the plants, with caterpillars attached, and stuffed them into a large bag.
That bag is now sealed up and ready for the municipal compost truck to pick up on Friday.
Armyworms can eat a garden to the ground in just a few days, which is why extreme steps are needed. If you see these in your garden, do not delay even one day in removing them!
Better news in the garden
Elsewhere in the garden, the carrot seedlings are sending up the “true” leaves that come after the first leaves. The first leaves that come out of a seed rarely look like the leaves on a mature plant.
For carrots, the first leaves are narrow and strappy. They are the ones that unfolded out of the seed, which is why the first leaves are often called seed leaves.
Do you see the seedling on the far right in the photo? The one leaf that is wider and more feathery gives a clue what the mature leaves will look like.
Also in the garden, there are tiny caterpillars on the pipevine plant. I planted the pipevine with these caterpillars in mind. If all goes well, a few of them will survive to become pipevine swallowtail butterflies, which are beautiful.