This is how you successfully fight the annoying pests

the essentials in brief

• The Colorado beetle larva in the third and fourth instar causes the worst damage in the vegetable garden.
• Colorado beetles are 7-15 cm tall with light yellow, black-striped wings. Larvae are bright red, later orange-yellow with black spots.
• Natural remedies against Colorado beetles are neem oil, tansy tea, Rock flour,(€ 12.33 at Amazon *) Coffee grounds, nettle liquid and manual collection.

Colorado beetle - profile and life cycle

The Colorado potato beetle is native to North America

The year 1877 is burned into the collective memory of commercial and private potato farmers. That year the first Colorado beetles were sighted in Germany, Holland and England. Within a few years, the beetles became the most dangerous pests for growing potatoes and other nightshades. Colorado beetles are causing such catastrophic havoc that they were even considered as a biological weapon in the middle of the last century.

In order to emerge victorious from confrontations with the Colorado potato beetle as a hobby gardener, you should be familiar with the appearance and habits of the voracious beetles and insatiable larvae. The following profile informs you briefly and compactly about all important aspects:

• Insect family: leaf beetles (Chrysomelidae)
• Beetle species: Colorado beetle, potato beetle, Colorado beetle (Leptinotarsa ​​decemlineata)
• Origin: North America, especially the state of Colorado
• Body length of adult beetles: 7-15 mm
• Appearance: roundish-oval, light yellow wing-coverts with 10 dark brown or black longitudinal stripes
• Appearance of larva: blood-red, later orange-red, black spots on the side and on the head
• Appearance eggs: cylindrical shape, orange-yellow in color
• Volume per year: 1 to 3 generations
• Activity: diurnal
• Lifespan: 2 years with one wintering
• Food plants: nightshade family, primarily potatoes, tomatoes, peppers, aubergines

There is a solid reason for the striking warning look of Colorado beetles. When danger threatens, the beetles excrete a poisonous defense secretion to keep enemies at bay. The toxin is harmless to humans. Birds, toads and other beneficial organisms could of course have a hard time in their stomachs. The pictures below illustrate the unmistakable appearance of Colorado potato beetle and potato beetle larva.

Consequential life cycle

For a successful control it is important to know exactly the life cycle of Colorado beetles. The real cause of the catastrophic crop damage is the voracious larvae in the last two stages of development. A brief foray into the life of a Colorado potato beetle illustrates its ingenious survival strategy, which causes annoyance among hobby gardeners and farmers around the world.

When the first potato plants sprout in spring, the Colorado beetle wakes up in its winter quarters deep in the ground. The beetles have hardly got the Hibernation rubbed out of the eyes, they devote themselves to ripening the delicate leaves. By the end of May / beginning of June, the adult Colorado beetles had strengthened themselves enough to start reproducing. Mated females lay their eggs in packets on the underside of the leaves. In one summer, a hardworking female places up to 1200 eggs in packages of 20 to 80 pieces. Given a two-year lifespan, a single female Colorado potato beetle will produce up to 2,400 offspring.

Bright red larvae hatch from the eggs within 5 to 12 days and immediately attack the leaves. Now we're getting one after the other. The larvae grow rapidly in the course of a total of four developmental stages. At the same time, their cravings for potato leaves steadily increase and in the last phase it takes on disastrous dimensions. After 17 to 20 days the spook is over, because the eating machines crawl into the ground to pupate.

Pupation and hatching in the ground take about two weeks. The vicious circle then starts all over again as the adult Colorado beetles fly out, eat their fill of leaves and bring the second generation to life in July. If the framework conditions are ideal, a third generation will develop in August and give the few surviving potato plants the rest. The beetles of this year's generations overwinter at a depth of up to 50 centimeters in the Garden soil.

Devastating damage

If the infestation is not controlled, Colorado beetles cause great damage

The spiral of annihilation starts when Colorado beetles crawl out of the ground after winter. The damage in the vegetable garden escalates with each development step. The following overview of the damage pattern illustrates why timely intervention plays a key role in the fight against potato beetles:

1. Maturation damage up to oviposition: slight damage to the leaf margins
2. First and second larval stage: moderate damage as edge and pitting corrosion on nightshade plants
3. Third and fourth instar larvae: incessant clearing until the affected plants are completely skeletonized

The primary source of food is potato plants, which is what the name of the pest refers to. In the absence of their favorite plants, Colorado beetles do not disdain other nightshades. These include tomatoes, peppers, eggplant and chilli.

Digression

Ladybugs devour Colorado beetle eggs

Fighting Colorado beetles - an overview of the methods

In the first and second stages, Colorado beetle larvae are particularly susceptible to control measures. Furthermore, the brood is not yet driven by an insatiable hunger, as in later stages of development. If the right resources are used at the perfect time, the third and fourth stage will not be eaten up in your garden. The following table names proven remedies against Colorado beetles:

Chemical sprays are not included in this overview for two important reasons. If you fight Colorado beetles chemically, it cannot be ruled out that your potatoes are contaminated with the insecticide. To avoid this problem, home gardeners invest a lot of time and effort in growing vegetables naturally. Furthermore, Colorado beetles and larvae have developed pronounced resistance to pesticides. Even highly toxic pesticides, such as DDT in the post-war years and pyrethrum in the 1970s, ran out of powder within a short time in the fight against the Colorado beetle plague.

Fight Colorado beetles naturally

When wrestling with the Colorado potato beetle, hobby gardeners give preference to natural products. The focus is on four methods that have proven themselves well in gardening practice. The exact procedure is explained in the following sections.

Collecting

Collection is tedious but effective

In allotment gardens, manual control of Colorado beetles, larvae and eggs cannot be topped in terms of effectiveness. Since the traditional method is associated with a high expenditure of time and effort, primarily small cultivation areas are suitable for collecting the pests. How to do it right:

• Best time: from May at regular intervals until August
• Best time of day: early morning hours
• First step: shake plants, collect fallen Colorado beetles and larvae
• Step Two: Examine the top and bottom of the leaves to crush eggs and egg packets by hand

Manual control raises the question for nature-oriented hobby gardeners: collecting Colorado beetles and then? Unfortunately, there is only one answer to this. Colorado beetles are on the black list of invasive species, the so-called Neophytes. Thus, the beetles move at eye level Brown rats, Nudibranchs, Mosquitoes and other creatures that are feared as biological invaders. It is forbidden to simply release neophytes because they put native species in distress. A tried and tested, gentle method is to throw collected Colorado beetles into a glass of water.

Nettle manure

Organic gardeners certify that nettle manure they produce themselves has the best effectiveness against potato beetles. If the natural product is used regularly from spring onwards, it will strengthen the resistance of young potato plants to pests. Spraying the leaves in good time spoils the brazen females' plan to place their eggs on them. This is how it works:

1. Stack 1 kg of fresh nettle in a wooden tub
2. 10 l collected Rainwater pour over
3. Cover container with wire mesh
4. Stir several times a day with a wooden stick

The fermentation process takes 10 to 14 days. Strain the finished nettle manure. In this state the liquid manure is too concentrated for plants. Before using as a natural remedy against Colorado beetles, dilute one liter of nettle manure with 8 to 10 liters of water. It is important to note that you spray the tops and bottoms of potato and tomato plants at least once a week.

Mint broth

Mint tea helps against young Colorado beetles

As an immediate measure against tiny Colorado potato beetle larvae shortly after egg hatching, mint broth has earned a good reputation. In order not to let the waiting time for finished nettle manure pass by unused, tackle the pests with freshly brewed peppermint tea. The important thing to note is that you are the real one peppermint Use (Mentha x piperita) and not a cultivated mint variety such as pineapple mint or strawberry mint.

Rock flour

There is a wafer-thin layer Rock flour on the leaves, approaching Colorado beetles seek the distance. You should therefore regularly pollinate the foliage above and below so that no eggs and larvae can settle here. Start the measure as soon as the growth starts, ideally before the pests break out of the ground. A positive side effect: rock powder also bends Aphids effectively.

Combating Colorado beetles naturally aims to significantly reduce infestation. Isolated copies will always elude the means. This means that your potato plants can live well and still give you a rich harvest.

Home remedies for Colorado beetles

The home remedies in the table above take the horror of a Colorado potato beetle plague when they encounter the first and second instar larvae. Applied at an early stage, plant leaves are prepared for the invasion of egg-packed female beetles. The following three home remedies ward off potato beetles:

Coffee grounds

Coffee is not only a great fertilizer, it also helps against Colorado beetles

With every cup of freshly brewed coffee, you also produce a powerful natural remedy against eaten potato beetle larvae. How to use the home remedy correctly:

1. Pour the coffee grounds out of the filter onto a plate or sieve
2. Let dry for 1 to 2 days
3. Sprinkle on the ground from the beginning / middle of May
4. From a height of 10 cm dust the plant leaves thinly (top and bottom)
5. Repeat treatment at 4 week intervals

You should not use the home remedy in the vegetable patch at shorter intervals. Coffee grounds have the property of lowering the pH value in the garden soil in larger quantities.

Mondamin

If you are looking for an inexpensive alternative to rock flour, you will find it on the kitchen shelf. Mondamin's extremely fine powder repels Colorado beetles and Colorado beetle larvae just as successfully. Apply the home remedy with a powder syringe when the plant leaves are still damp from the dew in the early morning and Mondamin is sticking well.

Wood ash

Hobby gardeners with their own chimney or grill oven swear by wood ash as a natural fertilizer. Less known is an excellent function as a home remedy for Colorado beetles. In order for wood ash to do its job perfectly, it must not contain any toxic residues, for example from lacquered wood or high-gloss magazines. If female Colorado potato beetles with eggs in their luggage come across plant leaves with a thin layer of wood ash, they turn away in disgust. If the ashes lie on active larvae, the rabble demonstrably dies of their appetite.

Coffee grounds, lunar amine and wood ash are lost as the sole means of control. In combination with natural methods, however, unexpected synergy effects unfold. A good example is treating endangered plants with nettle manure. As soon as the liquid has dried on the leaves, the second wave follows in the form of moon amine or wood ash.

Biological pesticides against Colorado beetles

Effective pesticides against Colorado beetles can be made from neem oil or tansy

Hard-boiled Colorado beetles are still able to get rid of two biological pesticides. A bio-insecticide is thanks to modern research. The alternative already served in the 19th Century as a tried and tested control agent against the dreaded pests and surprisingly has not lost any of its effectiveness to this day. Read the details below:

Neem oil

In the tropical regions of the world a splendid tree thrives, the fruits of which are bulging with much sought-after seeds. Neem oil, a biological insecticide against Colorado beetles, is obtained from these seeds. The natural ingredients are not immediately fatal to the pests. Rather, growth, reproduction and food intake are inhibited. The following products with neem oil as the main ingredient enjoy good reviews from beetle-plagued hobby gardeners:

• Bayer Garten organic pest-free neem
• Compo Bio Insect Free Neem
• Neudorff Neem Plus pest-free
• Natures Organic Pest Free Neem

The best time to use it is in the first five days after oviposition, ideally on the fifth day. In order to determine the exact date, please check the leaves of the nightshade family on the upper and lower sides every day. It's a good idea to have a magnifying glass with you so that the tiny eggs don't escape your attention.

Tansy tea

Ask an accomplished organic plant doctor: What helps against Colorado beetles? The answer comes like a shot from a pistol: tansy tea. Indeed, the biological pesticide has been used since the beginning of the Colorado beetle invasion and continues to achieve considerable success. Tansy is a widespread plant that thrives everywhere along the road. The hallmarks are the yellow cup-shaped flowers that appear from July to September. Its inner values, such as active tannins, lignans and essential oils, cannot be seen. Tansy tea is useful as an anti-potato beetle remedy:

• Put 5 g of dried tansy in a cauldron
• Add 1 liter of boiling water
• stir and bring to the boil
• Turn off the stove, put the lid on and let it steep for 15 minutes

Pour the cooled tansy tea into one Pressure sprayer. Wet potato and tomato plants with the spray as soon as you spot the first beetles or larvae. The efficiency is increased by first pouring cold water over the tansy leaves, leaving them to steep for 24 hours and only then boiling them.

Regularly switching between the bio-sprays is mandatory for optimal control success. Thanks to this strategy, you can counteract the development of resistance in the larvae. Ideally, the change always takes place when a new generation of Colorado beetles is in the starting blocks. If a neem spray was used in May, tansy tea should make life difficult for the beasts in July. The third generation will encounter a product containing neem again in August.

Defense plants against Colorado beetles

Nasturtiums keeps Colorado beetles away

Green protection in the fight against the Colorado potato beetle provide you with various defense plants. By creating a bulwark from these plants around the potato or tomato patch, you can optimize the control success of natural methods, household remedies and organic pesticides. The following species scare the Colorado beetle with floral vitality:

• Perennial flax (Linum perenne), height 30 cm, suitable for sunny locations with sandy, dry soil
• Nasturtium (Tropaeolum), height 15-30 cm, with climbing aid significantly higher
• Horseradish (Armoracia rusticana), height 30-50 cm, suitable for sun up to Penumbra with nutritious garden soil

as Border or green fencing, these types of plants exude special fragrances above and below ground, which disrupt approaching Colorado beetles. As a result of the irritation, the pests avoid the garden as a precaution and look elsewhere for locations for reproduction. Scientific arguments do not support the resistance to the pests. Since the perennials inspire with beautiful flowers, a test planting in the vegetable garden is definitely worthwhile.

Preventing Colorado beetles - tips & tricks

You can avoid confrontations with the Colorado beetle and its immensely greedy brood if you heed the following three tips. How to effectively prevent a plague in the potato bed:

• Dig up: Before planting seed potatoes, dig the bed at least 50 cm deep
• Wet the soil: Catch potato beetles crawling out of the ground with close-meshed protective nets
• Crop rotation retain: Ideally, change the cultivation area annually, at the latest every 2 to 4 years

The Colorado potato beetles that hibernate have preventive measures in their sights. By making the vegetable patch two in the spring spade dig deep, catch the pests in hibernation and kill them. With close-meshed soil nets as a reception committee, you deprive the hungry beetles of the option of immediately attacking the tender plants. An annual bed change removes potato and other nightshade plants from the reach of starved Colorado beetles that crawl out of the earth. In addition, a crop rotation during the year is useful. By planting other vegetables after the new potatoes, the development of a second generation of beetles stands on shaky legs.

frequently asked Questions

Can Colorado beetles fly?

Colorado beetles can fly very well

With its 6 thin legs, a Colorado potato beetle can walk badly. This handicap is balanced out by stable wings and endurance. In fact, potato beetles are excellent fliers that can easily move from one garden to the next for grazing. If a potato bed is crowded, Colorado beetles rise into the air and look out for new pastures.

What damage does the Colorado beetle do?

The Colorado potato beetle larva causes the greatest damage to the harvest, not the adult beetle. In the course of four developmental stages, the red larvae eat continuously on the leaves of potato plants and other nightshade plants. It is not uncommon for entire fields and vegetable beds to be completely bare. Particularly in the third and fourth instar larvae, Colorado beetle larvae are real eating machines that only leave the skeleton of a plant.

What does a Colorado beetle look like?

A Colorado potato beetle is 7 to 15 mm long and has a rounded, oval, hairless body. Distinctive identification are two shiny, light yellow cover wings, each with 5 dark vertical stripes. Black spots can be seen on the yellow-orange pronotum. The beetle has 6 thin legs and two easily visible antennae horns. The underside of the body is reddish brown. Males and females are visually indistinguishable for laypeople.

Where does the Colorado beetle come from?

The Colorado potato beetle is a leaf beetle and is one of the neophytes. This is how biologists refer to those animals that have been introduced from their homeland to other regions and have made their home there. Original origin is the state of Colorado in North America. This is what his second name Colorado beetle refers to.

Why do Colorado beetles not have natural enemies like most other pests?

Basically, any Colorado potato beetle would be a welcome treat for birds or frogs. These beneficial insects of course avoid the Colorado beetle due to the brightly colored warning clothing with the distinctive stripes. Likewise, the red larvae are consistently avoided by potential beneficial insects. Indeed, the warning is justified, because Colorado beetles are armed with a slightly poisonous defense secretion.

Tips

With a vital growth advantage, pre-germinated potatoes are well prepared for Colorado beetles and their insatiable larvae. The time window opens in mid-February for delicious early varieties such as “Cilena” or “Sieglinde”. Egg cartons, fruit crates and multi-pot plates are well suited for cultivation. In a bright, cool location at 12 ° to 15 ° Celsius, germination progresses quickly for planting at the end of March / beginning of April.