There is nothing more disappointing than doing all the work of planting and tending potatoes for them to be a large healthy meal for the Colorado Potato Beetle rather than you. Before we began gardening organically we fought these hungry pests with a barrage of noxious chemicals. Every old gardener I know told me “Dust those potatoes with Seven.” Well we did…and it didn’t work. This was around the time we were discussing going organic. The more I read about the pesticides and commercial fertilizers we were using the more scary my vegetables seemed. So we just quit using them.
I will never forget the last time we used commercial pesticides; it was a desperate attempt to save the potatoes. Those potato beetles ate the Seven dust and my beautiful plants. There were so many of them; we had been over run. The garden seemed a large mess to me when the idea to clean it flashed through my mind. I dug out the shop vac and towed it to the garden. My husband gave me the look he gives when questioning my sanity; but, he said nothing and fetched the extension cord. Within thirty minutes the hungry horde of beetles were snug in the vacuum and we were able to eat potatoes at the end of the season. As much fun as vacuuming your garden can be; there are things that can be done to prevent such excessive methods.
The Colorado Potato Beetle is a very adaptive insect. Despite Colorado getting all the blame, this insect likely came from Central America and it has been all over North America for a long time. They prefer the warm weather so they go underground for the cold months. In warmer areas they may have as many as 3 breeding cycles. Wherever you plant your potatoes they will show up; however, you can cut down on the infestation by practicing crop rotation. The potato beetle prefer plants of the nightshade family so it is best to rotate your tomatoes and potatoes together if you have limited rotation space. The suggestions on space of rotation vary depending on what you read; .3 miles or .5 kilometers is a safe distance. However if you have more limited space just rotate the best you can. The goal is to hinder these pests because really there is no stopping them completely. The other benefit of crop rotation is that you will be able to keep your soil nutrients more balanced. Each type of plant takes particular nutrients to grow; so if you keep the same type of plant in the same location the ground will get robbed of that nutrient over time.
As with crop rotation, mulching is just good practice. Mulching slows the weeds down and heavy mulching will keep you from having to till the rows. Every time you till the soil, nutrients are lost so less tilling means healthier soil. Mulching also keeps the ground from getting hard and holds moisture. If you are not sold on mulching at this point there is more. Mulching also attracts the insects that eat your plants; it is a natural pesticide. Beneficial bugs like Ladybugs love hay and they also love to eat the Colorado Potato Beetle’s eggs.
When it comes down to it hand removal of the Colorado Potato Beetle is the best method to protect your plants. The potato beetle is a slow mover so getting a hold of them is not an issue. If you have bug phobia wear gloves. These critters also cannot swim so as you pluck them from your plants put them in a can with an inch or two of water in the bottom. The adult beetles move a little faster than the young ones so you may have to tap the side of the can ever so often until you are finished and can dispose of them. The adult beetles and younger ones are easy to spot because they are bright colors that stand out against the leaves; however, you will have to look under the leaves for the yellow eggs and the newly hatched. The adults are striped and the younger ones are red. Be aware that if you dump the freshly picked beetles anywhere near your garden or your neighbor’s garden they will seek and destroy any potato and tomato plants they can get to. We have chickens. So I usually take the can of beetles far from the garden, in the barn where the chickens are fed and I place it next to their feed for a little extra treat.
Chickens are some of the most neurotic and hungry animals on the planet. Our chickens are true pasture range which means they do not have any fences and have the run of the place. There are issues with free running chickens such as sometimes they dig up your lovely mulch, eat your tomatoes and cucumbers, or follow you all over asking for more food; but, the benefits clearly outweigh all of that. Chickens eat bugs from sunrise to sunset. And while they are eating bugs out of the garden they scratch around and act as miniature rototillers. All that labor and then they pay you in eggs. Eggs from pasture raised chickens are much more nutritious than free range eggs.
BT and Neem Oil
Bt or Bacillus thuringiensis is a bacteria that attack the larva of the potato beetle and can be used in the early stages of breeding. And Neem Oil can be used on the adults to prevent their breeding cycle. Be cautious however with the usage of Neem Oil because you can harm pollinators such as bees that are necessary for your plants. The last thing we need is for bees not to reproduce. If you do use Neem Oil choose a time of day when the bees are not around and giving ample time for the oil to dry before they show up.
An excellent article on the entomology of the Colorado Potato Beetle from the University of Florida: