Fighting Colorado beetles – pests on potatoes

The Colorado beetle occurs all over the world. It was brought in from the USA. The first finds in Germany date back to 1877. Even then, the danger of the beetle was recognized and numerous efforts were made to destroy it. The reason is simple. I feed the beetles and their larvae from the potato plant. The beetles can destroy entire fields in a short time by eating all the leaves. With up to three generations of beetles per year (under good conditions) everyone can imagine that the Colorado beetle will quickly become a nuisance. Colorado beetles not only eat the leaves of potatoes, but also of almost all crops, e.g. tomatoes, eggplants, tobacco and a few more.

Colorado beetles hibernate deep in the earth. In June, eggs are then laid on the underside of the leaves of the potato plant. Each female can lay up to 1,200 eggs. After 3 to 12 days, the larvae hatch, which are reddish and have black spots on the sides and on the head. The larvae grow quickly. They molt three times in total. After 2 to 4 weeks they pupate in the soil. The beetle is ready after just two more weeks. It stays in the ground for a week before coming out.

The fight against the Colorado beetle

In the garden you can get the Colorado potato beetle under control quite easily. It is much more difficult for large agricultural areas. Chemistry is not the ultimate, either, because the beetles are increasingly developing resistance to the known agents. That is why there is a lot of experimentation with genetically modified potato varieties. These are said to be resistant to the Colorado potato beetle. In Russia and Eastern Europe in particular, there is hope in these potatoes.

prevention

The ultimate means of prevention has not yet been found. However, there are a few things that can be helpful. It’s best to try them out once. This is always the best way to form an opinion.

• Pest control nets are very cheap. They not only protect the plants from beetles, but also from caterpillars and maggots. At the same time, such a net offers protection from the sun and is still water and air permeable.
• Avoid mineral fertilizers containing nitrogen! Although they ensure higher yields, the plants are driven in the process. This seems to favor the Colorado beetle infestation.
• Determine the cultivation sequence every year!
• Appropriate choice of potato variety
• Early varieties have a growth advantage over the beetle. They are usually a little more resilient.
• Mixed culture also helps against the infestation. Caraway seeds, peas and spinach are cheap.
• Caraway seeds are said to be particularly effective. You just plant it in between.
• Mulching with fern and peppermint has proven to be a good measure.
• Nettle algae or rock flour help to strengthen the plants so that they can defend themselves better and do not lose their weight straight away.
• Natural enemies are ground beetles, caterpillar flies and toads

Home remedies

There is also no such thing as the ultimate home remedy. While researching the topic, I came across some interesting reports that mention means that really promise help. Here, too, you can only try out and test.

• Mint broth – depending on the size of the growing area, boil a lot of mint with water and then strain. This brew can be sprayed after cooling. It is beneficial to also spray on the leaves at the bottom.
• Coffee grounds – dry (heating or sun) and collect. When the young potato plants are about 10 to 12 cm high, sprinkle the coffee grounds over the plants. The process is repeated after 4 to 6 weeks. In time you can collect sentences again. The best time to distribute it is early in the morning when there is still dew on the leaves. The coffee grounds can stick to it. The beetles don’t like that.
• Planting peppermint between the potatoes – it really helps, but it is also dangerous. The mint spreads and at some point you can no longer get a grip on it. If you can, you should leave the mint in pots and plant it between the rows.
• Dust the larvae with rock flour

Best measure against the Colorado beetle

It is still best to collect the beetles, larvae and egg packets. When the females start to lay their eggs in mid-May, you should look under the leaves of the potato plant. The egg packets, which contain 20 to 80 eggs, are quite easy to see. Then it should be sprayed with the aforementioned mint broth. Both together should be an effective protection against the Colorado potato beetle.

In any case, it makes sense to always keep an eye out for beetles and larvae and to collect them regularly. This works best in the early morning hours, when the insects are not yet as agile.

It is also effective to use chickens or ducks, but this is not for everyone and is also not possible everywhere. These animals contain the beetle’s spread well.

Means for organic cultivation

Anyone who cannot keep up with the collection because the cultivation area is simply too large can use pesticides. Since many hobby gardeners want to do without chemicals, it is advisable to use organic preparations. They should be approved for organic cultivation. Recommended are:

• Natures Pest Free Neem from Scotts Celaflor – however, it has to be sprayed shortly after the eggs are laid. No longer shows great effect on adult beetles. Not dangerous to bees, broad spectrum of activity, product made from natural, renewable raw materials, active ingredient azadirachtin (main component of the seed of the neem tree).
• Spruzit pest free from Neudorff – based on rapeseed oil, spray against sucking and biting insects, also combats larvae and eggs, not dangerous for bees, but dangerous for the environment
• Natria fruit and vegetables pest-free from Bayer – combined active ingredients pyrethrins (obtained from chrysanthemums) and rapeseed oil, fights eggs, larvae and adult pests, protects beneficial insects, against sucking and stinging insects, only permitted in commercial gardens
• Garden organic pest-free Neem from Bayer – spray in the larval stage, against sucking and biting insects, but only helpful against the larvae, agent based on neem, but very toxic to aquatic organisms with long-term effects, only permitted in commercial horticulture
• Novodor FC – based on Bacillius thuringiensis. Contains Bt proteins (protein poisonous for eating insects) as food poison, against larvae, not effective against the beetles, larvae stop eating very quickly, die after 4 to 6 days, particularly effective with young larvae

Conclusion
The Colorado potato beetle is a nuisance and can cause great damage. It seems to appear en masse every few years. Otherwise, the population is likely to be limited. From the simplest it is safe to collect the beetles, larvae and eggs. Every egg that is destroyed means one voracious larva and one beetle less. However, if you want to free a larger acreage, you are usually at a loss. Coffee grounds and mint broth don’t do much for that either. In this case, you should resort to sprays. We recommend products that are approved for organic cultivation, i.e. natural products. They usually have their price, but ultimately you want to eat the tubers with pleasure. There are several remedies available, but not all are approved for household use. The best thing to do is to inquire at a specialist retailer.