If you’re trying to grow potatoes (or any member of the hemlock family or solanaceous crops) one of the most often encountered problems is the Colorado potato bug or beetle.
Larva and adults beetles prey upon potato plants by eating both the blossoms and the leaves.
In addition to potato plants, these voracious little beetles also lay waste to other members of the hemlock family, such as peppers, eggplant and not to mention creates tomato plant problems.
When plants loses a great number of leaves, its vigor and ability to produce fruit are hampered. All of these plants will suffer reduced production levels if potato beetles continue to consume your plants.
What Is a Potato Bug?
Colorado potato beetles (leptinotarsa decemlineata) are most commonly found in the southwestern areas of the United States. You will begin to see the adults emerge late in the spring time when you’re potatoes are just beginning to establish themselves and grow well.
Adult potato beetles, potato bugs or Jerusalem crickets are easy to spot because they are quite dramatically marked. Their wings are black and striped with a yellow-orange color, and their heads are orange with black spots.
You’ll find the adults amongst the foliage of your potato plants. Unless you intervene you will soon see clusters of reddish potato beetle larvae on the tips of your potato plant branches.
If you are growing eggplant, the potato bug larvae will be gray. As they get larger, you will notice the potato beetle larvae beginning to sport black dots on their sides.
How To Recognize Potato Beetle Damage
During the potato beetle larval stage these bugs are hungry little critters but where do potato bugs live?
They first go for the tastiest and most tender parts of plants. You can find them infesting gardens with solanaceous plants or those that are from nightshade family.
For this reason, they will usually eat the flower buds from potato plants before eating the leaves.
They move very quickly, and if interfered with they will strip all foliage from your potato plants.
It is important to note that this is more likely to happen when you plant a mono crop.
In other words, if you have all potatoes, tomatoes or other hemlock type plants you are more likely to lose your whole crop.
Crop Diversity Is Key
If you have a mixed crop, colorado bugs may ignore some plants and focus on others, so it’s a good idea to keep a diversified organic garden.
This type of garden is more likely to attract beneficial insects which are natural predators of potato beetles.
When you have a good assortment of beneficial fauna in your garden, you can be sure that potato beetle eggs, larvae and even adult beetles will be consumed.
You want to have a good mix of ladybugs, ground beetles and small wasps. In this way you can be certain that eggs, larvae and beetles will have to fight to survive.
The Lifecycle Of The Colorado Potato Beetle
Adult potato beetles can live through the winter by hiding under the bark of trees or other cover to protect them from freezing.
When the weather warms up in the middle of the spring time, they come out of hiding and seek out potato plants or other hemlock type plants.
Once they find the type of plants they need, they eat, mate and lay eggs.
Within a couple of weeks, the eggs hatch and the larvae will begin feeding on the plants. This goes on for another couple of weeks until the larvae become pupa.
From the laying of eggs to the time the pupa become adults can take 30-45 days.
The amount of time is dependent upon the weather. In cooler weather, this transformation takes longer. In warm weather the entire process usually takes about 30 days.
When you live in a warm climate, you may get a double dose of potato beetles every year!
When the cycle of metamorphosis takes only 30 days, it is entirely possible for it to be completed twice in a growing season.
How To Keep Your Potato Plants, Eggplants, Peppers & Tomatoes Relatively Free Of Potato Beetles
Organic control is most effective for pest management. You might think spraying pesticide would be a good idea, but you’d be wrong.
You will have far more success fighting off potato beetles with an arsenal of natural weapons.
There are a number of organic ways of controlling potato beetles and maybe some other pests such as tomato fruitworm, aphids, and others. Among them include:
- Pick the potato beetles off from the soil or plant as you see them.
- Attract beneficial insects to your garden.
- Line trenches between rows with plastic.
- Mulch the soil and plants heavily with straw.
- Practice crop rotation
These natural solutions are far better than chemical insecticides because as time has passed, the Colorado potato beetle has developed commercial insecticide resistance from a vast majority of brands.
For this reason, it is more effective to use a variety of organic methods to catch potato beetles off-guard.
One example is making use of essential oils such as a neem oil, which is known as an effective solution against garden pests.
Diatomaceous earth also does a great job of eliminating insects and other harmful insect pests in your potato fields.
Attract Helper Beneficials
The best beneficial fauna or natural enemy to help you in your fight against potato beetles include:
- Predatory Stink bugs (hemiptera pentatomidae)
- Double eyed soldier bugs (perillus bioculatus)
- Parasitic Wasps
- Domestic Fowl
- Ground Beetles
- Box Turtles
- Spotted lady beetles (coleomegilla maculata)
You can attract a lot of beneficial insects for biological control by planting flowers amongst your potato crops.
In addition to insects that will help you fight potato beetles, planting flowers will also attract pollinators such as butterflies and bees so it’s a win-win all around.
How To Get Rid Of Colorado Potato Beetle
Along with forming an alliance with beneficial fauna, there are a number of steps that you can take to keep potato beetles at bay. Among them are:
1. Rotate your crops. This is a very effective way to baffle potato beetles and to prevent them from being able to find your crops. It’s a good idea to alternate grains with tubers to prevent having potato beetles establish themselves.
2. Dig trenches between your rows of potato plants. These trenches should be a foot wide and dug at a 45 degree angle. Line each trench with black plastic. When the potato beetles fall into the trench, they will be trapped.
3. When your young potato plants have emerged and are growing well, mulch around them with straw or hay. Be sure to do this early enough that potato beetles have not yet found your plants. When they come looking and make their way across the straw or hay, they are very likely to encounter the one of the natural predators you have cultivated.
4. Use floating row covers to protect your potatoes once you have mulched them. Open them up once a week and examine your plants to be sure that potato beetle larvae or adults are not present. If they are, remove them by hand.
5. Keep chickens, ducks, geese and/or guineas. Once your potato plants are fairly mature (one foot tall) you can let your flock wander through them from time-to-time to pick off potato beetles.
6. Carry a bucket of warm soapy water with you when you examine your potato plants. It’s also a good idea to carry a little mirror with you so that you can easily examine the undersides of your potato leaves.
If you see larvae or adult beetles, remove them and drop them in the soapy water. Doing this every day will greatly reduce the number of potato beetles in your garden. Using an insecticidal soap is a good potato bug killer and will make killing pill bugs, sow bugs and potato bugs easier.
7. Plant potato beetle resistant varieties of potato such as “King Harry”. This type of potato plant has a great many leaf hairs, making them undesirable to potato beetles.
8. Mix buckwheat plants into your garden. Potato beetles don’t like them, but predatory wasps do. The blooms of the buckwheat plants will attract these beneficial garden insects at just the right time to help you battle potato beetles.
9. If you see lots of larvae on your plants, you may want to spray with organic spinosad insecticide. This organic pesticide is produced using fermentation.
It is save for indoor and outdoor plants, fruit trees, flower gardens, lawns and veggie gardens. It is listed as safe for use in organic food production by the USDA National Organic Program.
Another natural potato beetle control option is Bacillus thuringiensis. Learn more about Bacillus thuringiensis (bt) here.
10. Throughout the growing season, continue to add coarse mulch around your potato plants. This can be straw or hay or even grass clippings or leaves. This type of mulch provides habitat for natural potato beetle predators.
Potato Beetles Are Garden Enemy #1
Because they are so adaptable, reproduce so prolifically and wreak havoc with all kinds of hemlock crops, potato beetles are the scourge of many a gardener’s existence.
The challenge of coping with their notorious ways has spurred many a scientist into action.
You can find lots of interesting information at the websites of several major universities. Additionally, there is even a website dedicated entirely to the contemplation of the potato beetle problem.
It is Potatobeetle.org where you will find articles, tips, studies, anecdotal information and even potato beetle haiku and artwork submitted by young organic gardeners in the making.
The main thing you should remember when battling potato beetles is that you will probably never overcome them.
However, if you adopt a Wile E. Coyote sort of approach to them and keep devising one fiendish plan of attack after another, you have a good chance of keeping them at bay and having a bit of fun doing it!