If you are like most gardeners in northeast Ohio, you may be noticing some damage to your cucumber plants at this point in the season. Holes and brown spots on leaves like this…

or chew marks like these…

on your cukes themselves are telltale signs you are dealing with one of several common cucumber pests.

Insects can cause damage by feeding on your plants, but even more importantly, they can transmit diseases such as bacterial wilt that can do your cukes in altogether! But don’t worry, there are ways to keep pest insects in check and ensure that you will have more cucumbers than you can handle this and every season. (Keep in mind, these pests love other members of the cucurbit family, including squash and pumpkins, too!)

 

Culprit #1: Squash bugs

Squash bugs are grayish brown and shaped like an elongated shield.

They can be pretty big – I’ve seen some that are an inch long! They like to hide on the underside of leaves and are often seen attached at the butt like this (which means they are mating – no bueno!)…

If you see a squash bug on your plant, you can pick it off and squish it, or if you are too squeamish to do that, you can blast it with a puff of diatomaceous earth. Diatomaceous earth (DE)  is a powder made of the skeletons of tiny aquatic organisms called diatoms. Their fossilized remains are made of mostly silica, which kills hard bodied insects by absorbing the oils and fats from their exoskeletons. What a way to go!

Anyway, it works well on squash bugs with a few caveats. First, make sure you buy food grade DE and not the stuff they sell for treating swimming pools..

Second, wear a mask when you are applying it because this stuff is not good for human lungs, either. Last, diatomaceous earth can kill beneficial insects like bees, too, so never apply it to flowers that are in bloom. Using an applicator like the puffer shown here can help you target where the dust is going.

Perhaps the safest way to keep squash bug populations in check is by getting rid of their eggs before they even have a chance to hatch. The eggs look like little gold balls…

and are usually found on the underside of leaves along the veins. They can be tricky to pick off. I like to use a little stick to scrape them off, but some people swear by duct tape!

 

Culprit #2: Cucumber beetles

Cucumber beetles are yellow with black marking and come in two varieties: spotted or striped. We have both at Old Trail Farm, but I’m mostly seeing striped ones like these…

DE works on cucumber beetles, too, but they are much faster than squash bugs so that is not my preferred method of dealing with them.

A yellow bowl filled with water and one drop of dish soap like this…

is a simple and effective trap for cucumber beetles. They are attracted to the yellow color (which is the same as the flowers of their favorite plants), and when they fly into the water they can’t get out because the dish soap has broken the surface tension. As you can see…

the trap works, but it also affects other insects based on the same principle. It’s up to you to decide if the casualties are worth it.

My favorite method of insect pest control is to create a healthy garden ecosystem and let predatory insects control pest populations. Here we see two beneficial insects, a common ladybug larva…

and a couple of mating pink spotted lady beetles…

happily living their lives on our cucumber plants. Both of them eat soft bodied pest insects like aphids and mealy bugs, and also the eggs of other insects like our foes described above!

It’s important to note that you don’t need to eradicate pest insects completely in order to have healthy plants. Just make sure to keep their populations in check and your plants will be just fine.