Don’t be fooled by the pretty appearance of this little beetle. The Colorado potato beetle is an invasive pest on several crops, and mainly affects potato plantations. If you are a producer of potatoes or other solanaceous plants, you already know how formidable it can be. Its insatiable appetite for the foliage of your plants, coupled with its ability to multiply quickly, makes it a particularly difficult adversary to manage. Let’s discover this pest in detail and find the effective natural solutions developed by Agrobiotop to get rid of it.
- Presentation of the Colorado potato beetle
- Physical description and identification of the Colorado potato beetle
- Colorado potato beetle life cycle
- How does the Colorado potato beetle spread?
- What are the host plants of the Colorado potato beetle?
- What damage does the Colorado potato beetle cause?
- What methods of prevention against the Colorado potato beetle?
- What methods are there to combat the Colorado potato beetle?
Presentation of the Colorado potato beetle
The Colorado potato beetle is a beetle that is present worldwide. Originally from Mexico, it then colonized potato crops in the United States at the end of the 19th century before reaching Europe at the beginning of the 20th century.
Today it is a serious threat to our potato crops.
| Common noun | Colorado potato beetle, ten-striped spearman, |
| Scientific name | Leptinotarsa decemlineata |
| Order | Beetle |
| Family | Chrysomelidae |
| Origin | Mexico |
| Target cultivated plants | Potato and other nightshades (tomatoes, eggplants, etc.) |
Physical description and identification of the Colorado potato beetle
The adult Colorado potato beetle is easily recognizable. Here’s how to recognize it at its different life stages:
Adult
The adult Colorado potato beetle is between 10 and 12 mm long . Its body is rounded, longer than it is wide, and decorated with clearly visible yellow-orange and black stripes. Its head is yellow, marked with a V-shaped spot.
Larvae
The larvae, in their final stage of development, reach about 12 mm. They are distinguished by their red-orange color, punctuated with small dark spots and a black head. Equipped with robust mandibles, they are voracious towards the leaves of your crops.
Eggs
Colorado potato beetle eggs are small, about 2 mm, and orange-yellow in color. They are laid in clusters under the leaves, usually in groups of 20 to 50, making them easier to spot when inspecting plants.
Colorado potato beetle life cycle
Under ideal conditions, the Colorado potato beetle can produce up to four generations per year , although this frequency is generally limited to a single generation per year north of the Loire in France, where the climate is less favourable.
During the winter, adults burrow deep into the soil to hibernate, sheltered from the cold. With the return of spring and when temperatures exceed 10 °C, these adults emerge and begin a new reproductive cycle. Females are particularly prolific, laying up to 1,500 eggs in their lifetime. After mating, they lay their eggs in clusters of 20 to 50 under the leaves of your potato plants, thus providing protection for future larvae.
The eggs hatch quickly, in seven to fifteen days depending on the temperature, and give birth to larvae that are immediately active and ready to feed. For about fifteen days, these larvae consume the foliage of the plants with an insatiable appetite. At the end of this growth phase, the larvae leave the leaves to bury themselves in turn and enter pupation, a transformation process that lasts a few weeks. They then emerge as adults ready to continue the cycle.
How does the Colorado potato beetle spread?
The Colorado potato beetle moves efficiently, either by flying over long distances or by natural elements, such as wind or water. This mobility allows it to quickly invade new plots of crops, even those isolated from infestation sources. Its ability to disperse explains its success as an agricultural pest in many countries.
What are the host plants of the Colorado potato beetle?
The Colorado potato beetle feeds mainly on nightshades: potatoes, tomatoes, eggplants and peppers are the main victims of its voracious appetite. It can also attack secondary hosts, such as black nightshade, a wild plant that offers it an alternative refuge when agricultural crops are less accessible.
What damage does the Colorado potato beetle cause?
When Colorado potato beetles invade your crops, their damage can be quickly visible and very destructive. Larvae and adults attack the foliage, devouring the leaves until sometimes the stems are bare. This defoliation can seriously weaken your potato plants and, in severe cases, compromise the harvest.
The tubers themselves are not immune. When exposed, the larvae do not hesitate to feed on them. Their action reduces the quality and quantity of production.
In addition to direct damage, the Colorado potato beetle makes plants more vulnerable to bacterial diseases , such as brown rot ( Ralstonia solanacearum ), which spreads more easily on weakened plants.
These repeated attacks make the Colorado potato beetle a particularly formidable adversary for your crops because it impacts the health of the plants, but also the final yield of your production.
What methods of prevention against the Colorado potato beetle?
To limit the invasion of Colorado potato beetles in your fields, here are some simple and effective preventive practices:
- Monitoring : Regularly inspect the foliage and especially the underside of the leaves to quickly spot eggs, larvae and adults. This vigilance will allow you to detect the first signs of infestation and take action before the damage gets worse.
- Crop rotation : Rotate crops each year to disrupt the Colorado potato beetle life cycle. By changing the environment each season, you reduce the risk of a lasting establishment.
- Row spacing : Spacing out rows of potatoes makes it easier to detect Colorado potato beetles early and collect them manually if necessary.
- Association of repellent crops : certain plants, such as peas, beans, garlic, castor oil plant, mint, eggplant or tomato, can help mask the smell of potatoes, thus reducing the attractiveness of your plots for Colorado potato beetles.
- Encourage the presence of natural predators (lacewings, ground beetles, etc.)
What methods are there to combat the Colorado potato beetle?
While manual collection remains an effective method on small areas, it remains impractical on large plots.
At Agrobiotop, we have developed natural solutions that effectively combat this potato pest:
