The mealybug: how to fight and treat your plants


Some plants are particularly vulnerable to attacks by mealybugs. These are able to completely cover a plant or shrub in just a few days, creating considerable damage. It is therefore imperative to treat the plants concerned to fight against the mealybug. But the beast could not be more tough and the fight is difficult. Sometimes it is even hell. Zoom on the mealybug and the best solutions to get rid of it effectively.

What is the mealybug?

The mealybug belongs to the family of Pseudococcidae which consists of over a thousand species of mealybugs. Mealy is the one we see on many of our plants (indoor and outdoor). One would have to live in Antarctica or in the Arctic to be more or less free from this scourge – at least outdoors – because the cochineal is everywhere in the world. She likes them hot and humid atmospheres where it is developing at full speed. In France, the mealybug is ubiquitous.

This biting-sucking hemiptera insect settles on certain plants and the female feeds on their sap. It is therefore a polyphagous insect. We quickly identify its proliferation by the presence of a kind of white cottony mass on the leaves, armpits and stems.

What plants are most popular with mealybugs

These are undoubtedly the citrus who pay the costs of the scale insect invasion. And this citrus-loving strain ranks among the worst pests. But the mealybug spares neither orchids, nor Anthurium, nor shrubs with red fruits. It also attacks ferns, crotons, different species of ficus, papayas, cacti, roses, kalanchoes, and even (it’s a shame) certain varieties of carnivorous plants! This list is unfortunately far from exhaustive.

There are different mealybugs like that of the vine (Pseudococcus affinis) which also ravages passionflower and tomato plants, that of the orange tree (Planococcus citri) devastating citrus fruit but also fruit trees, many leguminous plants as well as some ornamental plants, or even that of greenhouses (Pseudococcus longispinus) which is also called the long-tailed mealybug.

We must in any case be aware thatit only takes one infested plant at purchase to contaminate all those in the house or garden that are susceptible to attacks by mealybugs. So you have to be particularly vigilant when choosing plants in a garden center or other because there is no question of introducing this sworn enemy into its plant setting …

The different forms of mealybug control

We must act at the first signs that suggest the invasion of a plant by mealybugs. There are three ways to get rid of it, namely:

  • By chemical control,
  • Through biological control,
  • By homemade solutions.

Chemical control of the mealybug

Here, it is a question of resorting to a chemical product of the type systemic insecticide. In this category, we find for example:

  • Thiacloprid, an organochlorine insecticide,
  • Imidacloprid, a powerful pesticide that Agriculture has been using around the world for about thirty years,
  • Dimethoate, an insecticide which belongs to the category of organophosphate products and which is none other than a neurotoxic.

These treatments penetrate the shell of the pests and attack their nervous system. It goes without saying that these mealybug control chemicals are certainly efficient, but are not without causing ecological problems. They are in fact toxic to beneficial insects and animals in general as well as to humans.

However, using this type of product is possible provided that it is not on a large scale, and that theuse either only punctual. For example, we can eradicate all the mealybugs that invade indoor plants. This saves your plants and as a result, many hours of work spent looking after them so that they are beautiful and healthy.

Biological control of the mealybug

In order to spare human health, that of animals and more generally our environment, it is strongly recommended to give preference to natural solutions to get rid of mealybugs. It’s possible. To do this, we then opt for biological control using for example:

  • The Green Chrisope (Chrysoperla carnea), a neuroptera which, in the larval state, attacks adult mealybugs. It is a sacred predator of cochineals that we can therefore invite with open arms… There are around 300 lacewing eggs to biologically treat between 6 and 12 plants.
  • The Ladybugs, beetles which feed on mealybugs but also aphids among others (just to kill two birds with one stone if necessary),
  • The hymenoptera among which :
    • Pseudaphycus maculipennis
    • Anagyrus fusciventris,
    • Anagyrus pseudococci,
    • Metaphycus flavus,
    • Encarsia citrina,
    • Coccidoxenoides perminutus,
    • Coccophagus scutellaris…

The use of these garden friends can hardly be done in the house or the apartment. We therefore reserve this biological control for all plants that are grown outdoors, on the terrace, the balcony or in the ground and which cochineals are fond of.

Treating mealybugs naturally gives excellent results if the right predators are chosen. It is therefore imperative ask a specialist in a garden center, for example, or with a passionate and serious landscaper to be oriented towards the most effective solution possible.

Homemade recipes for treating plants invaded by mealybugs

There are many homemade recipes known for ages that can be prepared in a few minutes to eliminate, at least in part, this type of vermin that inexorably attacks plants. Here’s how to do it:

  • 1time solution: Dip a cotton swab inrubbing alcohol mixed with a small amount of water and then pass it on the affected plant parts.
  • 2th solution: Pour into a spray bottle exclusively reserved for this use 100 cl of lukewarm water, 2 tablespoons of methylated spirits, 2 tablespoons of vegetable oil. Shake well then after the preparation has cooled completely, spray the plants invaded by mealybugs. The application must be repeated several times until the disappearance of hemiptera insects. Note that methylated spirits can very well be replaced by White vinegar and vegetable oil with real black soap.

Finally, in case of very strong attack of mealybugs, and if the various control solutions that we have adopted have not made it possible to destroy all of these pest insects, it is necessary – even if it is heartbreaking – cut back very severely the plants concerned. This is essential to eliminate infested branches and twigs and to prevent contamination of other plants.

Photo credit: Chamaiporn Buamas, Department of Agriculture, Thailand

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