I have a lemon that has recently been attacked by the cochineal. I managed through the use of white oil and pesticides to eliminate, even mechanically, the parasites. I noticed that however many leaves and some branches have blackened, presenting black dots that are quite widespread that I believe are fumaggini.
How can I fight them? I removed the leaves most affected but the branches remain attached.
Could you give me some indications?
Thank you for contacting us about your plants.
Lemons, Citrus Limon, are arboreal plants belonging to the citrus genus. They originate in India and were introduced to the Mediterranean by the Arabs. The plants have irregular branches, evergreen ovate leaves and white flowers with purple hues that produce yellow fruits (+ large in the cedar) with an aromatic peel thanks to essential oils and juicy pulp. There are natural hybrids "Cedar lemons" which have intermediate characteristics between the 2 species.
Mealybugs are insects that live on the underside of the leaves and live by sucking the sap up to cause the total decay of the plant.
Although the struggle is difficult, it is normally carried out with foliar treatments with insecticides based on white oil.
These insects emit a sugary honeydew which turns out to be an excellent substrate for the development of fumaggini, fungi that cause the formation of blackish crusty spots that smear fruit and branches. The fight is carried out with cupric products that block the spread of the fungus.