Hello. The blackish powder present on some branches and needles is called sooty mold and is a fungus that develops on the sweet secretions released by certain pests. Considering the biology of these pests and the period in which we are, it is recommended to remove the affected parts of the plant (as far as possible – from the lower part of the crown), with well sharpened and disinfected tools (e.g. ). The removed parts are recommended to be destroyed by burning. Subsequently, it is recommended to carry out a copper-containing treatment with a fungicide such as , in a dosage of 20 g/10 L water, according to the instructions on the label. As the tree is tall, in order to ensure a more uniform distribution of the solution, it is recommended to use a sprayer such as , to which a rod such as or is attached. It is important to prepare a volume of solution corresponding to a single treatment (respecting the mentioned dosage), because the already prepared mixture does not have a shelf life longer than 24 hours. More information about the optimal application of plant protection treatments can be found in our article: Phytosanitary treatments - environmental and labor protection.
If during the pruning you notice the presence of pests (including larvae, pupae, growths, very fine webs, white fuzz or others), please come back with details of their appearance and behavior, as well as clear, focused photographs.
Also, during this period we recommend the use of a fertilizer with a high potassium content, , as recommended in the product description. It has the effect of increasing the resistance to frost and improving the water balance of trees and shrubs.
Additionally, at the beginning of the growing season (April-June), it is recommended to carry out treatments with an insecticide with a wider spectrum of control, such as (in a dose of 1.5 ml/ 10 l of water), by spraying. You may consider applying two to three treatments, spraying the solution as close to the stem and branches as possible, at an interval of approx. 15-30 days – especially if you notice pests on the conifer. To increase the effectiveness of the insecticide, it is recommended to add to the solution an adjuvant such as , in a dose of 2 ml/10 L of insecticidal solution.
In order to detect the presence of potential pests and to monitor and control certain insect populations, during the next growing season you may consider using adhesive traps, such as . The pests are attracted by the color of the paper and stick to the special adhesive.
More information on this topic can be found in our articles: Sooty mold – Symptoms and treatment and Spruce, pest information and treatment. The future evolution of the conifer cannot be predicted.