Almost every gardener knows the annoying, itchy bites of flea beetles that inevitably appear after working in the vegetable patch. The little creatures are even worse for many vegetable and ornamental plants, because their appetite for fresh, juicy leafy green is huge. Typical signs of an infestation are pitting in the leaves, and vegetables and flowers grow only hesitantly. Fortunately, flea beetles can be easily controlled or even prevented with non-toxic, simple measures - here we will tell you how this works best.

Fleas leave behind ugly feeding damage, which can lead to complete crop failures

Table of Contents

Show all
  1. the essentials in brief
  2. Fight
  3. damage picture
  4. prevention
  5. What are flea beetles?
  6. way of life
  7. frequently asked Questions

    8. the essentials in brief

    • Fleas can be fought with strips of glue or beneficial insects
    • Adult flea beetles are only 4mm in size
    • Fleas leave countless tiny holes in the affected leaves
    • Weeding not only helps against weeds, it also prevents flea infestation

    Combat flea beetles effectively

    Especially in spring you should keep a close eye on your seedlings and young plants and regularly check for flea infestation - a quick reaction is important at this point in time to save the plants. Later in the year the main concern is to prevent the larvae from pupating and the adult beetles from overwintering. To do this, it makes sense to regularly loosen the soil in the vegetable patch, remove weeds and keep the soil slightly damp - but never wet! - to keep. The measures described below also help.

    Especially in the garden, the principle "a lot helps a lot" does far more harm than good.

    glue strips

    This simple remedy is quite effective in controlling adult flea beetles, but needs to be repeated throughout the growing season. Buy a bucket of caterpillar glue from a garden store, coat several wooden boards with it and place them at regular intervals between the vegetable plants. The flea beetles jump on it when there is a problem, stick and can finally be collected and disposed of together with the boards.

    Natural enemies

    The favorite hiding places of flea beetles (genus "Phyllotreta") such as piles of leaves and wood also attract many animal garden helpers, where the small beetles, their larvae and other pests are on the menu. Bring these beneficial insects into the garden in a targeted manner (some insects can be purchased from specialist retailers, for example) and create pleasant habitats for the animals, such as hiding places or an inexpensive insect hotel. (11.33€)

    These animals target flea beetles:

    • Hedgehog
    • shrew
    • ground beetle
    • predator beetle
    • parasitic wasp

    attractants

    Also quite simple and easy to implement is a lure plant that is planted in the middle of the bed and is supposed to keep the flea beetles away from the other plants. Use a type of plant that is particularly popular with the animals - such as broccoli or radish - which should be slightly larger than the other bed dwellers. Plant them in the bed together with their pot so that you can later dispose of the eggs and larvae at the same time. In contrast to the other bedding plants, keep the attractant dry and do not hoe it. Once the bugs have settled on it, on a hot and dry day, wrap the plant in a plastic bag and remove it from the bed. But don't wait too long, otherwise the animals will look for another food plant.

    This is how you recognize flea beetles in good time

    Due to their small size of only up to four millimeters in length, adult flea beetles are difficult to recognize. However, the animals leave a characteristic damage on the leaves and stems of the plants they have eaten, which makes them easy to recognize. The leaf surfaces are riddled with numerous round, tiny holes. These are usually smaller than four millimeters. The greatest damage occurs when large numbers of overwintering flea beetles attack young plants between April and May and literally eat them up. The long hind legs of flea beetles are characteristic.

    tips

    A flea infestation should also be combated because the feeding sites on the leaves and other parts of the plant serve as an entry point for certain fungi, such as those from the genus Phoma, and thus cause additional damage through a fungicidal infection.

    Which plant species are most affected?

    Due to the large distribution of the large oilseed rape flea beetle, plant species from the cruciferous family (bot. Brassicaceae) are particularly badly affected in the garden. This plant family includes numerous important vegetable and ornamental plants, as the following table shows:

    vegetable plants ornamental plants
    Radish, rocket, broccoli, kohlrabi, white and red cabbage, cauliflower, radish, Chinese cabbage, pak choi, tomatoes, potatoes, peppers Levkoje, gold lacquer, night violet, blue cushion

    But not only cruciferous plants, other plant species are also affected. For example, flea beetles are often found on basil or hollyhocks. As a rule, flea beetles only eat the leaves of the plants, but in rare cases the tubers in the soil can also be affected. For example, the larvae also find the radishes, which are often sown early in the year, very tasty.

    Prevention is better than fight

    Effectively preventing an infestation with flea beetles is actually not that difficult - but with a little effort. At best, you deprive the animals of their livelihood and ensure that the conditions favorable for an occurrence are not given in the first place. You have to know that the leaf beetles appear mainly in warm and dry weather - and also attach great importance to rest.

    An infestation can be significantly reduced or even completely prevented if you only regularly hoe through the vegetable patch, weed and disturb the animals with this work. They quickly look for a quieter environment. Furthermore, you should keep the soil moist by regular watering and/or spraying - of course only to the extent that it is conducive to plant growth, waterlogging is also harmful after all - and cover the root area with a layer of mulch. This keeps the moisture in the soil, so that the larvae on the roots are also hampered in their development.

    Anyone who hacks regularly hides a flea infestation

    The right time

    The measures mentioned are to be carried out from the end of March / beginning of April and then regularly during the summer months. In the spring you disturb the overwintering adult beetles, and between June and August you finally prevent the larvae from pupating. However, be careful not to destroy the roots of the plants.

    Mixed culture in the vegetable patch

    In a mixed culture, the gardener plants different types of plants together in one bed instead of occupying it with a single variety. The advantage of such a mix is that the different plants strengthen and complement each other - and the entire harvest is not immediately endangered, as is the case with a monoculture. Just as cabbage plants attract cabbage fleas, certain plants, most notably onions and garlic, also deter them. Therefore, plant both vegetables close to the cruciferous vegetables - but be careful, brassicas and onions or garlic are not necessarily ideal planting partners, as they in turn hinder each other in other respects.

    Regular watering with plant manure

    Instead of cultivating a mixed culture with cabbages and onions, you can also water the plants with plant manure that you have prepared yourself. This is a tried-and-tested biological household remedy that is easy to produce and, in contrast to chemical sprays, has no undesirable side effects. This method not only repels flea beetles (and other pests and pathogens, too), but also provides fresh, easily accessible nutrients to the vegetable crops. In addition to onions and garlic, tansy (also known as wormwood), which is often found along the wayside, and wormwood (bitter mugwort) are also suitable for this purpose. You can find all the ingredients either in your own garden or in the great outdoors.

    How to make your own plant manure

    The production of an effective plant manure requires one thing above all: a lot of time. The mixture has to ferment for at least ten to 14 days, which is why you should let it grow in a warm but dark place in the garden - and because of the odor development, above all, secluded place. Do not fill the mixture into a metal container, but preferably into a plastic or enamel bucket. Use a wooden stick to stir.

    Step-by-step instructions for effective plant manure

    1. harvest one kilogram of suitable plant material freshly
    2. chop it up carefully and put it in a bucket
    3. Pour ten liters of fresh water over it
    4. add a handful of rock flour (14.13€) to create the smell
    5. Cover the container only with a jute net
    6. stir daily

    The liquid manure is ready when the liquid no longer foams when stirred. Now dilute it with water in a ratio of 1:10 and water your plants with it.

    digression

    Mulch as a low-odour alternative to liquid manure

    Unfortunately, the production and use of plant manure is quite an odor-intensive affair. Alternatively, you can use onion skins, minced garlic, and shredded tansy to mulch vulnerable vegetable beds. The following video shows this very well using nettle mulch as an example.

    youtube

    What are flea beetles?

    Contrary to what their name might suggest, flea beetles are not fleas. In fact, behind the misleading name are different types of leaf beetles (lat. Chrysomelidae). However, the little creatures, which are only between one and a half to three millimeters in size, have one thing in common with their namesakes: Thanks to their powerful jumping legs, the adult beetles hop away like fleas when disturbed.

    Both the adult animals and their larvae are phytophagous, as biologists call herbivores. The insects feast on the leaves of various plant species as well as on their roots and therefore cause great damage both in commercial agriculture and in domestic vegetable gardens. While the larvae live underground, the adult beetles are on the surface after pupating and multiplying very diligently. There are several generations per year, which annoy the gardener considerably throughout the growing season.

    Adult flea beetles eat leaves, the larvae damage the roots

    Different types

    However, not every flea is the same, because it is a genus comprising around 200 different species. Psylliodes, as the flea beetles are scientifically called, are represented in Europe alone with around 100 species and their subspecies. These have mostly specialized in certain plant genera and species and can only be found on these. Since it is not a single species, the leaf beetles have a very different appearance. They can be bluish-black or bronze, blue, grey, yellow or even striped - the variety of the oval, elongated beetles is extremely large.

    These three types are particularly difficult for garden owners:

    Flea Art Latin designation Look Preferred plant species
    Potato Flea Psylliodes affinis dark brown carapace, yellow vertical stripes Potatoes, tomatoes and other nightshades
    Large rapeseed flea Psylliodes chrysocephalus shiny, blue-black to dark green carapace Arugula, radish, radishes, various types of cabbage and other cruciferous vegetables
    hop flea Psylliodes attenuatus bronze to metallic green lustrous carapace, yellow-red legs and antennae Hops, hemp and nettles

    The most common is the large rape flea, which likes to make itself comfortable in the vegetable patch and find all kinds of delicious food there.

    way of life and reproduction

    Flea beetles become active with the warm spring temperatures, with the female animals laying their eggs primarily in small holes in the ground on the roots of the preferred plant species, but also on their leaves. The white larvae hatch about ten days after the eggs are laid and feed underground on the delicate filamentous roots of the plants. The damage caused here initially remains invisible, but is not yet too serious. After about three weeks, the larvae pupate in a soil cocoon and finally hatch between June and August. Only the adult beetles cause considerable damage through their feeding activity, which manifests itself as follows:

    • leaf tissue: is scraped off with the mouthparts
    • leaf surface: primarily young plants are destroyed
    • scuffing: The damaged tissue dries, turns brown and tears

    The older, well-established and therefore more robust plants are less at risk than the young plants. Seedlings and seedlings in particular do not yet have enough resistance to withstand flea infestation and die off quickly.

    While an infestation of kohlrabi or broccoli does not appear too dramatic - after all, plant parts other than the leaves are consumed here - clearly visible flea tracks on leafy vegetables such as rocket or savoy cabbage are not very appetizing.

    Adult flea beetles overwinter in the garden

    The adult flea beetles overwinter in the garden and mainly find shelter in the soil, but also in layers of mulch and leaves, under plant remains (also on the compost!), in piles of stones and wood, and in hedges. From here, given the right temperatures, they start their campaign of destruction early in the year and should therefore be combated in a sustained manner.

    digression

    Fleas in the flowerpot

    The most annoying leaf beetles can occur not only in the garden, but also in the greenhouse and even on indoor plants. Fleas in the house are a particularly annoying matter, after all they cannot be fought here with the usual means such as hoes and plant manure. Instead, there is an old household remedy that reliably helps: Put a few matches in the flower pot with the sulphur-head side down and keep the substrate slightly moist. The leaf beetles cannot tolerate the sulphurous material and disappear.

    frequently asked Questions

    How can I protect my young plants from pests?

    Healthy, strong plants are usually very well able to defend themselves against pests and pathogens. Strengthen your plants with an adequate supply of nutrients. In particular, the regular application of compost (starting early in the year) has proven to be useful and plant-strengthening. You should also cover young plants in spring with a close-meshed insect protection net (mesh size 0.8 mm) or garden fleece.

    Is it true that flea beetles also avoid spinach and lettuce?

    Experience has shown that flea beetles also like to eat lettuce plants, which is why these are not really suitable as an avoidance strategy. The animals really don't like spinach. Try mulching with shredded spinach leaves - but be careful: snails also like to eat the leafy greens. Therefore, a snail fence or another defense strategy makes sense to keep the voracious animals away.

    Can't I also fight flea beetles with insecticides?

    In principle, it is of course also possible to get rid of the annoying flea beetles with insecticides from specialist shops. There are some suitable preparations for this, but they all have a serious disadvantage: They not only poison flea beetles, but also other insects and also ensure that your vegetables are also contaminated. Better are plant protection products on a biological basis, such as the plant protection products already mentioned or neem oil.

    Is it true that rye flour helps against flea beetles?

    In fact, rye flour is an old household remedy against flea beetles and drives them away. To do this, dust the plant completely with the flour, and good results can also be achieved with algae lime.However, both are only effective against the adult animals and not against their larvae, and powdering can also prevent the plant from photosynthesizing and thus impair growth and development.

    tips

    Always wear gardening gloves and long clothing when working in the vegetable patch, as flea beetles like to bite. The bites cause an itchy rash and can be dangerous for allergic people.

Category:

Animals in the garden