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Mealybugs, also known as mealybugs, are among the pests that can infest both indoor plants and a wide variety of plants in the garden. These pests usually colonize areas of the plants that are difficult to see. An infestation is often only detected when it is already advanced. If we do not act immediately, these mealybugs can multiply explosively and the more severe the infestation, the more difficult it is to combat successfully.

Characteristics

  • Class: Insects
  • Insect Family: Mealybugs (Pseudococccidae)
  • German names: Mealybugs, mealybugs, root lice, blood lice
  • known species: more than 1000
  • Differences: The type of hair and length of the tail threads vary depending on the species
  • Body size: 1 to 12 mm
  • Body Color: Pink with white smeary hairs
  • Plant damage: sucking damage, release of poison and honeydew

First steps

If you notice an infestation with mealybugs or mealybugs, you should act immediately to prevent them from spreading. The earlier an infestation is recognized and treated, the more promising it is to combat it. First, affected plants should be isolated. Then you shower them with as strong a jet of water as possible, provided they can tolerate it.

If necessary, cut off particularly affected parts of the plant. Plants that are heavily infested with pests should be cut back completely if possible. Of course you can also collect isolated pests, but this is very tedious. Mealybugs also lay their eggs in the substrate of indoor plants. As a result, affected plants must be potted and the substrate renewed. Rinse the roots thoroughly with cold water to completely remove old remains of soil and eggs.

The pot is also thoroughly cleaned and additionally disinfected with alcohol. Of course, the drainage material used must also be thoroughly cleaned or replaced. Then you can pot the plant in fresh substrate.

In the case of particularly susceptible plants, it is advisable to incorporate rock flour into the new substrate. Most of the time, these measures are not enough to completely eliminate a mealybug infestation, so further steps are required. This can be the use of natural predators, household remedies or chemical agents, whereby the latter should only be used in extreme emergencies.

Tip: If you want to be absolutely sure that the new substrate does not contain any germs, spores, larvae or pests, you can disinfect it for 20 minutes in the oven at 180 - 200 degrees or for 5 minutes in the microwave at 800 watts.

Mealybug on an orchid plant

control options

There are many ways to combat it. Beneficial insects are generally a great help, but usually cannot cope with a stronger infestation without additional measures. In addition, e.g. the use of home remedies is recommended. Systemic agents from the trade are very effective, but they are not entirely harmless, especially when used in the living area.

Natural predators

Like most creatures, mealybugs have natural predators. Most of the pests live on the trunks, branches and leaves of plants. Of the many mealybug species, the citrus mealybug and long-tailed mealybug are the most common. The citrus mealybug in particular can be combated very well with suitable beneficial insects.

For plants indoors, conservatories and greenhouses, the Australian ladybird and lacewing larvae are suitable. There are several species of parasitic wasps in the garden. In order for these to work effectively, they must be deployed precisely according to the instructions.

Australian ladybug

  • the Australian ladybug or its larvae only use indoors
  • deliver as soon as possible after receipt
  • keep windows and doors closed for a few hours after application
  • Ladybugs need temperatures between 22 and 30 degrees
  • air humidity of 70 to 80 percent is just as important
  • Open the packaging directly at the point of application
  • Deploy beneficial insects according to the sender's instructions
  • do not touch or squeeze the animals
  • best time during twilight
  • now they are less active
  • Depending on the severity of the infestation and the culture, repeat the whole thing after 2 - 4 weeks
  • under ideal conditions, they will eat up to 400 pests in a day

lacewings

The larvae of lacewings can also fight mealybugs. They have a relatively wide range of prey and their larvae are extremely voracious. These twilight-active beneficial insects can be used all year round in the house, in the conservatory or greenhouse.

In order to become active, the larvae need temperatures of at least 12 degrees, increased humidity is not required. After pupating, the adult lacewing finds a way out. Here, too, repeated use is usually necessary. Lacewing larvae destroy about 100 pests per day.

parasitic wasps

Leptomastix dactylopii, Leptomastidea abnormis, Anagyrus pseudococci and Coccidoxenoides perminutus are suitable for combating mealybugs and mealybugs. They are mainly used outdoors. They need temperatures above 21 degrees and humidity of 60 to 70 percent.

Mealybugs on an orchid leaf

It gets difficult at temperatures below 15 and above 35 degrees. Leptomastidea abnormalis also needs strong light, provided it is not too cold. In addition, they should not be used in strong sunlight. In the case of a heavy infestation, they can also be used together with lacewing larvae or the Australian ladybird.

Tip: In the greenhouse, it can make sense to fight ants at the same time, because they would fight the beneficial insects to protect the mealybugs. Mealybugs are coveted sources of honeydew for ants.

Pros and cons of beneficial insects

Advantages and disadvantages of using beneficial insects

Benefits:

  • Use and deployment of beneficial insects simple and uncomplicated
  • only naturally occurring insect species are used
  • leave no chemical residue
  • Application does not pose any risk of chemical vapors, mists or dusts
  • environment is protected
  • Beneficial insects used also occur in nature

Disadvantage:

  • limited shelf life of beneficial insects obtained from the trade disadvantageous
  • not all pests are always reached
  • as a result, repeated use is usually required
  • not to forget the purchase price

It is all the more important to naturally settle beneficial insects in the garden or to encourage their settlement. You can do this, for example, by sowing wildflower mixtures, planting hedges and shrubs, installing nest boxes or insect hotels and creating piles of leaves, stones or bark. All of this offers numerous useful insects shelter and hibernation opportunities as well as winter feeding places.

chemical preparations

Many hobby gardeners resort to chemical, systemic agents to combat pests. The effect of this occurs quickly and lasts for several weeks. Nevertheless, such means should only be used if nothing else has helped. They are offered in liquid form, as powder or granules and applied by spraying, pouring or dusting.

The most common means against mealybugs include special granules that are spread on the substrate, sprays or insecticide sticks that are stuck into the ground. These agents are usually very aggressive. In addition, there is a risk that the pests will get used to certain active ingredients and the effect will consequently decrease or not occur at all.

Mealybugs on the back of an orchid flower

In addition, one should keep in mind that these substances not only kill pests, but also beneficial ones. Their breakdown products accumulate in the plants and thus get into the food chain, where they endanger the health of humans and animals as well as the environment. After application, a longer waiting period must be observed, especially with fruit and vegetables, before they can be harvested.

They must be stored and disposed of properly. After chemical treatment, many use additional beneficial insects. Here, too, a waiting period of at least 6 weeks usually has to be observed. So why not try conventional home remedies first, which can be very effective depending on the severity of the infestation.

home remedies

There is a large selection of home remedies that are suitable for combating mealybugs. In this way, very effective solutions for spraying or spreading can be produced from different agents and substances or plants without exposing yourself or others to any danger. In addition, some home remedies can be easily combined with the use of beneficial insects. Preparations containing oil are said to be particularly effective in the fight against mealybugs, but not all plants tolerate them.

soap solutions

  • For a pure soap solution, dissolve 2 tablespoons of soft or curd soap in 1 liter of water
  • Moisten a cloth with it and wipe off infested parts of the plant
  • or apply the agent using a spray bottle
  • very suitable for sensitive plants such as orchids
  • Dish soap not recommended instead of soap
  • they are very aggressive
  • cover the substrate with foil before spraying
  • this is to prevent the soap solution from getting into the substrate
  • higher effectiveness by adding 20 ml of high-proof alcohol (spirit)
  • Alcohol dissolves the waxy outer covering of mealybugs
  • this allows the soft soap to act on the pests and dry them out
  • Mist the top and bottom of the leaves, twigs and stems with the mixture
  • Solution must also reach hard-to-reach places on the plants
  • This is the only way to kill pests and their eggs
Mealy bugs on orchid buds

Due to the alcohol, this variant is unsuitable for particularly sensitive plants. This home remedy should also not be used in direct sunlight. Both methods require repeated use to get rid of the mealybugs completely.

alcohol

Pure, high-proof alcohol without any additives is also suitable for combating mealybugs and mealybugs. However, since not all plants tolerate such strong agents, it is advisable to first test their tolerance on a small, hidden spot. Incidentally, cacti tolerate the alcohol without any problems.

For an initial infestation, the alcohol can be dabbed directly onto the lice using a cotton swab. If it is already advanced, spray it on or wipe the pests off with a cloth soaked in alcohol. This treatment method must also be repeated until no more infestation is detectable.

Oily agents

Oil-based products are said to be particularly effective in combating mealybugs. But not all plants tolerate them either. Soft-leaved species in particular are very sensitive to this, including orchids. Preparations containing mineral oil should be avoided if possible. Rapeseed, neem and olive oil are better tolerated.

For a sprayable solution, mix about 2 tablespoons of oil with 1 liter of water and some soft soap. The soap acts as an emulsifier, allowing the water and oil to mix. The mixture is then best applied with a brush or sprayed onto the plant. Here, too, the addition of about 15 ml of alcohol can intensify the effect. This should be repeated at intervals of 2-3 days.

There is a solution especially for the garden that can be used both to ward off and to combat sucking and biting insects. You need 10 drops of lavender oil, 1 liter of lime-free water and a tiny drop of washing-up liquid. Instead of lavender oil, you can also use the same amount of tea tree or neem tree oil.

The ingredients are mixed together and infested plants are misted with it. After 2 - 3 days you repeat the whole thing, if necessary more times. As a preventive measure, the plants can be sprayed with this solution once a week from April to August.

Tip: If possible, you should avoid applying oily products to large areas, because the oil clogs the pores of the plant, causing additional damage and, in the worst case, even dying.

Vegetable brews and broths

nettle brew

For a nettle decoction, put 1 kg of fresh herb in a container, pour 10 liters of boiling water over it and cover the container. The mixture is left to infuse for 3 days and stirred once a day. Then it can be poured through a sieve or a cotton diaper and the plants sprayed with it.

Tansy or wormwood decoction

To prepare a suitable brew, pour 5 liters of boiling water over 150 g of chopped up tansy leaves or wormwood and let it steep for 10 minutes. Then pass the mixture through a sieve again, let it cool down and spray on infested plants. As a rule, at least three repetitions are necessary at intervals of 8 days.

tobacco brew

For a corresponding tobacco brew, mix 200 g of tobacco with 1 liter of hot water and leave the brew in a closed container for about an hour. Then strain and apply the mixture to the pests, preferably with a brush.

Mealybugs on an orchid bud

garlic broth

To make a garlic broth, pour 1.5 liters of boiling water over 50g of finely chopped fresh garlic. This concoction is then allowed to steep for 30 minutes and then poured through a fine sieve or alternatively through a gauze or cotton diaper. After cooling, the brew can be applied to the plants using a spray bottle.

Saponins - Sud

Saponins (lat. 'sapo' soap) are natural substances found in ivy and chestnuts, among other things. When added to water and shaken, a soap-like foam is formed, hence the name saponins. To prepare a suitable spray, heat about 45 roughly chopped ivy leaves or about 2 handfuls of halved chestnuts in one liter of water and leave the whole thing covered in the boiling water for half an hour.

Then let the brew steep for half an hour. After it has cooled down, pour it through a cloth or fine sieve again and use it on the spot. This brew has the additional advantage that it is also said to be effective against ants.

Tip: Regardless of which plant broth you choose, multiple applications are usually required until the last pest is gone.

homeopathy

Homeopathy can also be very helpful in pest control. A corresponding homeopathic remedy for mealybugs is Sulfur C 200. Good results have been achieved with orchids, among other things. Dissolve 5 of these homeopathic globules in 2 liters of lukewarm water, mix well and the remedy is ready to use. Affected plants can be sprayed, sprayed or doused with it. If no improvement is visible after three days, repeat the whole thing.

causes

Unfavorable site conditions are usually the cause of pest infestation. Too low humidity is the most common cause. A lack of light and excessive nitrogen fertilization can also be the cause of pest infestation. Already weakened plants are particularly vulnerable.

Indoor plants are infested mainly in winter. Houseplants that are commonly attacked are orchids, cacti, palm trees, ficus, cypress grass and gardenias. In the garden, fruit trees, mallows, hydrangeas and boxwood, among others, are affected. Another cause can be the purchase of an already infested plant, so that the pest is brought in with the new plant.

damage picture

For many plants, the damage is almost the same. Mealybugs or mealybugs suck the plant sap and release a toxic secretion into the plant. In addition, the plants are covered with sticky honeydew. The consequences are yellow and wilting plant parts, stunted growth and restricted vitality. These pests and their larvae also colonize the root area of the plants. If the damage is not recognized as a pest infestation, an infestation can spread very quickly and lead to the total loss of one or more plants.

Mealybugs on an orchid

prevention

In order to avoid a pest infestation in the first place, attention should always be paid to optimal site conditions and avoiding an under- and oversupply of water and nutrients. Fertilization that is too nitrogenous is often problematic. In the garden it is advisable to encourage the settlement of beneficial insects. Plants should be checked extensively for pest infestation and possible diseases when you buy them.

By regularly spraying the plants with a cold water extract from yarrow, nettle or field horsetail, you can strengthen them and make them more resistant, because healthy plants are less susceptible. In addition, neighboring plants such as savory, nasturtium, chervil or lavender can help keep pests away.

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Garden maintenance