I found Colorado Potato Beetles on my potato plants today. These pests eat the leaves of the plant, which can diminish yields after the plant is flowering. The bugs love nightshades ( Solanaceae), which includes potatoes, tomatoes, and eggplant. They also supposedly eat peppers and other plants.
Please check your plants for beetle adults and larva, which are easily visible. Also check the undersides of leaves for orange egg clusters. I’ve found some on vine weed near the potato plants as well.
Recommended treatments are spraying beetles and eggs with soapy water, gently scratching off eggs, sprinkling diatomaceous earth around the plants (only effective when dry), mulching, and allowing ladybugs to eat them. See the resources below for details.
Use discretion with removing eggs and larva, as ladybugs look similar to potato bugs at this stage. Potato beetle eggs are more yellow while ladybug eggs are more red
And thats the catch with diatomaceous earth. It kills potato beetles AND ladybugs. Everything has a cost. I wait until i feel like I have to, and potato bugs ARE a have to. One is too many…
When a pest gets bad enuf,
I apply DE with an old sock knotted shut after filling it with DE. The light patting on the undersides of leaves gives a better application than my hand crank dust fogger, and limits the dust to the plants i want it on. I swing the sock with my right hand, while using my gloved left hand as a bounce backstop for the leaf that im treating.
I recently bought a red tube trap for cabbage looper butterflies - the pretty white butterflies that lay their eggs on any brassica. It seems like Any given green looper caterpiller can consume an entire leaf of Kale. And I cant catch them or fund the green eggs. Ive heard that each egg laying might have up to 12 eggs. So between leaf eating beetles that leave paper punch looking holes, and the loopers, we are back to buying our kale.
So I saw a Cabbage Looper Trap at Johnsons Garden Ctr - and despite the high price, decided to give it a try. It hasnt caught a single white butterfly yet, after a week above my kale. But the attractant in the sticky trap, has already attracted and trapped HUNDREDS of leaf eating beetles. The are close to the shape of ladybugs, but black, and smaller than a small ladybug. Tiny. I had no idea we had so many leaf beetles. Or DID have them. Im looking forward to more or prettier kale.
Both pests will leave alone my spinach, peas, and other flora. Ok the tiny beetles started in on my arugula.
UPDATE:
After 1 week of monitoring and intervention, I have seen far fewer bugs - 2 adults today from 12 last Saturday. I’ve also seen signs of a healthy ladybug presence that should help keep them under control. Working on mulching and planting herbs, beans, and marigolds to deter further infestations.
Great work Matthew! I have not seen any potato bugs on my plants or the community plants, although I did that something had been chewing on my sweet potato.
Update: found a bunch of larva (~24) yesterday. They live to hide under leaves but will be easily seen when it’s sunny out. Seems like I will need to stay vigilant
Another update: found a handful last Sunday, and I see larva periodically. Going to harvest soon and dispose of the plant matter to hopefully root out the infestation