Have you found small dots resembling cotton balls on your garden or house plants? Then you have discovered mealybugs. These plant suckers can do a lot of damage and must therefore be fought. In this article, we will tell you how this works best.

Mealybugs infest ornamental and crop plants alike

Table of Contents

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  1. Identify mealybugs and mealybugs
  2. Effectively combat mealybugs
  3. Beneficial insects against mealybugs
  4. Effectively prevent mealybugs - the pests don't stand a chance
  5. frequently asked Questions

    6. Identify mealybugs and mealybugs

    There is no such thing as "the" mealybug, instead - like its close relative, the scale insect - there are around 1000 different species. Around 65 are classified as plant pests in Germany, with the citrus mealybug (Planococcus citri) being particularly common. This not only affects leaves and shoots with preference, but also likes to nest in the roots. That is why this variety is also called root aphid. You can recognize them by the numerous "cotton balls" on the root neck and in the root area.

    damage and symptoms

    Mealybugs are usually easy to see with the naked eye

    The specific type of pest - which in any case cannot be determined by laypersons - is not relevant for successful control. You can recognize an infestation with all mealybugs by these symptoms:

    • Lice sit under a layer of white wax with cotton ball-like threads
    • are often found on the underside of the leaves
    • or in the drive axils
    • often also on the roots and the root neck
    • Leaf spots, stunted and curled leaves
    • Leaves later dry up and fall off
    • Stunted growth and dying of the plant when heavily infested
    • white, greasy residue on and near the plant
    • sticky honeydew

    The sticky residue is the sweet excretions of the pests called honeydew. These cause further problems because they attract ants and are colonized by sooty mold and sooty mold. So if you notice increased ant activity on certain plants, especially in garden plants, an infestation with mealybugs or other plant lice such as aphids or scale insects is not unlikely.

    tips

    Simply wipe away sticky leaves and soot

    If the leaves of the plants affected by mealybugs are covered with a blackish film, it is sooty mold. This is a fungus that feeds on honeydew and only attaches superficially to leaves and shoots. You can therefore simply wipe the surface carefully with a cloth dipped in lukewarm water. You should do the same with the sticky residues of the pests so that the photosynthesis of the affected crop is not disturbed.

    These plants are particularly often affected

    Mealybugs particularly like to sit on citrus plants such as lemon or orange trees. But the pests can also often be found on orchids, cacti, palm trees and other indoor plants. In the garden, in addition to hydrangeas, other herbaceous perennials and herbs are threatened by infestation.

    Healthy and strong plants can usually defend themselves, but if the plants are weakened by an unsuitable location or incorrect care, an infestation is likely. Mealybugs and mealybugs occur mainly in warm, dry weather, such as in the summer months or, for houseplants, towards the end of winter.

    Combat Mealybugs Effectively - What Really Helps?

    "Why should I resort to toxic (and expensive!) chemicals when there are effective antidotes growing in the garden?"

    When it comes to combating mealybugs and effective crop protection, you have a number of options. Don't jump to the chemical bludgeon, even though it may seem easier at first - toxic chemicals have a host of subsequent problems. Instead, we have put together some home remedies that have been tried and tested against the plant suckers here.

    First Aid Measures

    With a moderate infestation, it is often sufficient to rinse the infested plants thoroughly at regular intervals

    As soon as you have identified a mealybug infestation, you must isolate the affected plants - otherwise other houseplants will quickly become infected. Furthermore, these first aid measures help to counteract further spread:

    • Rinse affected plants with a strong jet of water
    • Cut back heavily infested parts of the plant
    • Collect isolated mealybugs, e.g. B. with the help of a toothbrush
    • Pot out severely infested plants and remove remains of soil

    Once these steps are completed, take further action. You can find out which ones make sense and how to use them in the following section.

    Make spray yourself - this is how it's done

    Spray cures based on easy to produce have proven to be particularly effective

    • Soft soap (44.90€) and alcohol
    • garlic
    • fern
    • and nettle

    exposed.

    Soft soap and alcohol

    youtube

    A spray made from liquid soft soap and denatured alcohol is almost a classic in the fight against mealybugs and other pests. This home remedy is very effective, but is not suitable for all plants. Therefore, before use, carry out a compatibility test in which you initially only apply the solution to a small area. Then wait a few hours: If the plant shows no reaction and no changes can be seen in the area, carry out the spray treatment. If, on the other hand, spots appear or the treated leaves curl, it is better not to treat them.

    Prepare the soft soap-alcohol mixture as follows:

    1. Stir in a tablespoon of liquid soft soap or dish soap
    2. in a little warm, lime-free water.
    3. Add a tablespoon of denatured alcohol.
    4. Caution: denatured alcohol is highly flammable! No open fire and no heat source nearby!
    5. Dissolve everything in a liter of soft water.

    Now fill the spray into a suitable spray bottle and spray the infested plants with it extensively. Do not forget the undersides of the leaves and the leaf axils - this is where the mealybugs like to sit. Alternatively, you can dip a cotton swab into the solution and dab each louse individually.

    vegetable brew

    Plant extracts based on garlic, nettle or fern are much better tolerated by many plants, especially orchids. You collect the latter two ingredients in nature, where both are found in abundance. For stinging nettles, be sure to collect leaves and stems from specimens that are about to flower - these have the highest percentage of active ingredients.

    And that's how it works:

    • You need 200 grams of nettles or 100 grams of fern or garlic.
    • Use whole bulbs of garlic with the skin.
    • Chop all parts of the plant as small as possible.
    • The better the active ingredients can be extracted.
    • Pour hot water over the plant material.
    • However, the water must no longer bubble.
    • Let the brew steep for about 24 hours.
    • Strain off the plant parts.
    • Pour the brew into a spray bottle.

    Then use the agent as a spray or water the affected plants with it. It is important that you do the cure several times at intervals of several days. This is the only way to catch all mealybugs, especially those that have just hatched from the eggs.

    Mealybugs on the roots - what to do?

    If the roots are infested with mealybugs, they should be thoroughly cleaned and potted in fresh soil

    On the other hand, if the mealybugs are on or in the roots, first pot the plant. Subsequently

    • remove any adherent substrate
    • and dispose of this
    • thoroughly clean the planter
    • and disinfect it with alcohol
    • rinse the roots thoroughly in the shower;
    • and immerse them in a garlic or nettle broth for about 15 minutes

    After this treatment, place the plant in fresh substrate and keep an eye on it. If the mealybugs appear again, repeat the treatment.

    digression

    Which biological pesticides also help?

    Biological pesticides, for example based on pyrethrum (obtained from chrysanthemums) or neem (obtained from the seeds of the Indian neem tree) reliably help against many pests, just not against mealybugs. At least that applies to externally applied agents. These do not penetrate the solid protective layer under which the harmful insects are located. Instead, you can buy special products that you simply add to the irrigation water or stick into the substrate as sticks. The plant absorbs the active ingredients so that they get into the plant sap - and thus attack the mealybugs from the inside.

    Take action against mealybugs and mealybugs with beneficial insects - completely naturally

    Beneficial insects - i.e. useful because they are predatory insects - have proven to be very effective in combating mealybugs and other pests. But be careful: You must not use them together with plant protection products (not even based on neem etc.!), as the beneficial insects are also killed by them. Help against mealybugs:

    • ladybug
    • lacewings
    • parasitic wasps
    • hoverflies
    • predator beetle

    You can get the natural predators of the mealybugs in specialist shops where the animals are sold as larvae. Apply according to the package directions provided, paying particular attention to the recommended temperature and light levels. This is the only way for the beneficial insects to develop as desired. After treatment, the insects will disappear on their own.

    In the garden you should ensure a healthy ecological balance in which useful insects and other animal helpers such as bees, bumblebees, butterflies, birds and hedgehogs feel at home. This way you keep the pests in check from the start. Cultivate many umbelliferous plants, as these are among the preferred food plants of beneficial insects - usually only their larvae are predatory.

    digression

    Never scratch off mealybugs!

    One often reads the “tip” to simply scrape off the mealybugs and mealybugs, at least in the case of a small infestation, and thus remove them. It is better not to do this, because under the protective layer there are not only the actual louse but also their eggs and young larvae. If you scrape the layer, you will only kill the adult louse - but you will pass on its tiny eggs and larvae unnoticed. As a result, the little animals continue to multiply happily.

    Effectively prevent mealybugs - the pests don't stand a chance

    Too much or too little water favors a mealybug infestation

    To prevent an infestation with mealybugs or other pests in the first place, these preventative measures are useful:

    • Pay attention to optimal site conditions for each plant.
    • Avoid over- or under-supply with water.
    • Avoid over- or undersupply with fertilizer.
    • In particular, nitrogen-rich fertilization weakens the plants.
    • For indoor plants, keep the humidity high.
    • Overwinter them - depending on the type and variety - as cool and light as possible.

    Garden plants are strengthened by regularly spraying or watering them with nettle or horsetail stock. You should also avoid monocultures, as they encourage pest infestation. Plant neighbors such as lavender, nasturtium, savory, garlic, onions, leeks (ornamental leeks) and chervil keep many pests away.

    frequently asked Questions

    Are mealybugs also dangerous for humans?

    Don't worry, mealybugs are not dangerous to humans or pets. The pests feed exclusively on nutritious plant juices, which is why only garden and house plants are at risk.

    Where do the mealybugs come from anyway?

    In most cases, the pests are dragged home with newly purchased or gifted plants. Well-hidden individual specimens are not even noticeable when making a selection, and plants that are only slightly affected often still look very healthy. However, if the conditions at home are right, the plant lice multiply explosively. A dry, warm room climate is particularly beneficial for their development.

    When are mealybugs most common?

    Mealybugs appear on indoor plants all year round, in the garden you will only find them during the growing season. In winter, the pests go into hibernation, just like the plants, after all, no plant juices flow in the cold season. This is different with indoor plants, at least if you cultivate them warm all year round.

    Can mealybugs tolerate cold? Does it maybe help to put the infested houseplants out on the balcony?

    Unfortunately, mealybugs and scale insects are quite insensitive to climatic changes. They occur in both dry and humid room air and can even tolerate frosty temperatures. Therefore, it is pointless to put infested indoor plants on the balcony in winter - the pests will certainly survive the cold shock. Only your plants will die, since most exotic plants come from the tropics or subtropics and are therefore not frost hardy. During the summer months, however, it can be advantageous to place infested plants outside - this makes control easier.

    Can mealybugs actually fly?

    In fact, mealybugs can fly, usually only males. Outwardly, they resemble the whitefly, so confusion is sometimes possible. The male mealybugs and mealybugs die after mating, while the females build a protective cocoon and thus become immobile. But beware: These pests can reproduce by virginity, fertilization is not necessary!

    tips

    Also worth trying is paraffin oil, which you apply directly to the mealybugs with a swab. You can then carefully remove them.

Category:

Animals in the garden