Hi, I have twenty cherry laurel plants in large pots in the garden. Every year I have to fight because they always get sick in the same way:
the gnawed leaves and the yellowed tips then dry and crumpled. You see so many small black animals that if they eat them, they look like small cockroaches.
What product should I use?
Change all the earth of the pots because it is infested? I no longer know what to do, I thank and greet
unfortunately the prunus laurocerasus tends to be affected by a series of pests and diseases; among the most widespread insects, surely the cochineal, which generally does not nest on the shoots, but prefers the thin stems, or the base of the petioles of the leaves. In addition to cochineal, in spring, the buds are attacked by aphids: insects with a mouthpart that stings the leaf blade and sucks its lymph; in addition to ruining the leaves mechanically, aphids are often also carriers of viral or bacterial diseases, which penetrate the plant through their saliva. By eating the sap, the small insects also tend to expel the excesses of sugars, which then flow onto the healthy foliage, where they are colonized by dark mushrooms, giving rise to a classic or disorder, called fumaggine. Because of all these problems, it is important to eradicate the aphids as soon as they are noticed on the plants, also because they can produce more generations during spring and summer. So we tend to vaporize the plants with products based on pyrethrum, or even specific insecticides, such as imidacloprid, already in early spring, in order to kill the first insects, without giving rise to subsequent generations. I remind you that insecticides are preferably used in the evening, and possibly when there are no flowers in the garden, so as to avoid hitting bees and other useful insects. Aphids often tend to disappear from the plants when the heat arrives, but not always; however, they are often removed from the plants simply by vaporizing the foliage with water; clear that this method, although completely natural, does not prevent the possibility of a rapid return of insects. And even if they do not come back, somewhere they will go, and if it is not on the other plants of our garden, it will be on the plants of the garden of our neighbors…. If we dislike them, it can also have an interesting implication, but I don't think that in the long run it will be completely positive.