A member of the Coccoidea family, the mealybug is a pest that is particularly feared by gardeners, as it attacks vegetable plants as well as other garden plants, fruit trees and houseplants. And once established, white mealybugs, mealybugs or shell mealybugs (black shells) are difficult to dislodge and tend to spread. For the sake of your plants, you must act quickly once the infestation is declared. Discover the plants targeted by these pests and what they risk, but also the symptoms of an infestation and the natural solutions to eliminate them in accordance with the environment.
What are the risks of a mealy bug infestation and the plants at risk?
These biting insects are after the sap of our green plants, trees and shrubs. They can attack the foliage, stems, roots, trunks or branches as well as the fruits of plants. This will then have the effect of weakening your plants and altering their good development, even going so far as to kill them. On fruit trees and vegetable garden plants, it can also compromise the harvest if not treated. In addition, these small beasts secrete a honeydew that attracts fungi. They can therefore cause the appearance of fumagine. This cryptogamic disease will leave a black layer on the plants and slow down their growth.
Plants at risk are fruit trees as well as succulents, ornamental shrubs and indoor plants if the latter are too humid and poorly ventilated. Mealybugs are particularly to be watched on :
-Citrus, grapevine and fruit trees (apple, fig, etc.)
-Oleander and laurel
-Cacti and succulents
-Hydrangea, bougainvillea or hibiscus
How to recognize a mealy bug infestation?
You suspect an invasion, but want to be sure? Here are a few signs that you can’t go wrong:
-The presence of tiny insects in the leaves, visible especially along the veins or at intersections when you have good eyes
-Cottony, sticky or mealy, whitish clusters (the insects are hiding underneath)
-Small waxy shields or brown hulls
-Viscous and sticky honeydew droplets secreted by this insect after consuming the sap of a plant (it attracts ants)
-The foliage becomes more and more yellow and the young shoots become deformed
-Flowering is stopped
-The trunk dries out and the bark cracks
-A black deposit appears (fumagine).
If you recognize these symptoms, do not delay in treating the plant, as it can quickly contaminate the rest of the garden. If the plant in question is too badly affected, it may be necessary to burn the most infested parts or even the entire plant. Never add it to the compost bin, however, as this can infest the compost. If the plant can still be saved, because it is neither too infested nor dead, try the natural solutions below, which are as effective (if not more so) than the phytosanitary products available in garden centers.
Home remedies against scale insects
Whatever treatment you choose, you will have to repeat it 7 or 8 days later. In fact, it is essential to carry out several spaced applications. This allows you to get rid of the mealy bugs, but also the larvae and eggs!
1) A recipe based on black soap against mealy bugs
You can simply brush the affected parts with a small brush induced organic liquid black soap. If you need to treat a larger area or several plants, it may be more practical to concoct a spray product for more convenience. In this case, to a liter of water, we will add a teaspoon of black soap (or dishwashing liquid), a teaspoon of methylated spirits or white vinegar and a teaspoon of rape oil. You can also add 2 drops of essential oil of sweet orange for more effectiveness against these parasites.
2) The alcohol at 90 °
The alcohol at 90° is excellent to limit their progression. To do this, simply clean the foliage with a cloth soaked in rubbing alcohol. Then, take care to rinse the leaves with water. You can also use the same recipe as above and replace the rubbing alcohol with rubbing alcohol. The result will be just as effective.
3) Potassium permanganate
Potassium permanganate is very dangerous for the environment and aquatic organisms. It is therefore forbidden to use it in the garden. On the other hand, it can be used carefully and episodically for your indoor plants. To do this, you can buy bags of potassium permanganate at a dose of 0.5 g in a pharmacy. Two of them are then diluted in a liter of water and a tablespoon of black soap or dishwashing liquid is added. Then spray it on the infested plants.
4) Nettle manure and garlic infusion
For outdoor plants, nettle manure is a very effective and natural solution. You can also use an infusion of garlic heads. To do this, you must immerse them for 5 minutes in hot water, then let them sit for a day to infuse the water. This decoction can then be filtered and used to treat the affected plants. The mealy bugs will not resist!
5) Biological control of scale insects
Invite natural predators of mealybugs into your garden to drive them out of your green spaces for good. The ladybug in its larval state is your best ally here. In the trade, look for the species Chilicorus nigritus and Cryptolaemus montrouzieri, which are formidable in case of invasion. And in addition, it will bring a little life to the garden!
6) The water jet
Hosing down an infestation will not stop it. However, it is very effective and very useful to destroy any insects invisible to the naked eye on large plants.
And in garden centers? You will find specific anti-cochineal treatments, including pyrethrum-based insecticides, as well as pheromone-based male traps. However, our ecological recipes based on black soap will be effective enough to avoid these unnecessary purchases!
I have 30 years of experience and i started this website to see if i could try and share my knowledge to help you.
With a degree a Horticulture BSc (Hons)
I have worked as a horticulture specialist lead gardener, garden landscaper, and of course i am a hobby gardener at home in my own garden.
Please if you have any questions leave them on the article and i will get back to you personally.