Trees and shrubs are even more vulnerable to diseases and pests than animals, because they cannot somehow indicate their condition. And if you notice that the cedar is turning yellow on your site, know: this is a cry for help from an oppressed coniferous plant.
Cedar turns yellow: causes of the phenomenon and methods of struggle
Possible causes of yellowing
There are several reasons why the cedar may turn yellow, we will consider each individually.
- Insect damage. Yellow needles are the first sign of a lack of nutrients in a tree, since parasites feed on them in the form of tree sap.
- The young age of the plant. In the early period of development, cedar does not have a powerful immune system, which is why it is sensitive to changes in living conditions and is more vulnerable to pests and diseases.
- Stress. Basically, it occurs due to unfavorable weather or a transfer.
- Improper care. Excessive watering or lack of water, a low amount of nutrients, drought - all this can cause yellowing of the needles.
Yellowing due to pests
Insect damage to the tree is one of the reasons for the yellowing of cedar needles.
- An ordinary engraver. In late spring, this beetle becomes a real misfortune. Males gnaw many holes in the bark so that the female can lay the larvae in them. Areas around such “nests” die off, and cedar begins to actively produce resin in an attempt to get rid of parasites. Unfortunately, the tree often dies.
- Hermes is pine. It is small and difficult to detect. As a result of its vital activity, a white bloom is formed on the needles, including the Hermes larvae. The adult insects are brown and feed on cedar sap. With significant damage, the plant begins to experience a lack of nutrients, which manifests itself in the form of yellow needles.
- Aphid. Prefers to live in the area of young shoots. The main food is plant sap.
- The scutellum is a small body with a hard back, brown, sometimes gray. With extensive damage, the needles first turn yellow, then the needles are dropped.
- Moth. The parasite lays eggs on old needles. The incubation period is 3 weeks. The larvae feed on young needles and buds. The pine moth can kill the plant.
Ways to fight
To get rid of parasites, it is necessary to apply insecticides.
Some of them can be used without special training, others are available only from specialists. So, an ordinary engraver cannot be brought out on its own.
To get rid of Hermes pine, twice a month, according to the instructions, are used:
- Fufanon;
- Aktar;
- Actellic.
The affected areas of the tree must be removed
From pine aphids, karbofos has proven itself well. They are sprayed with the crown of the plant. To get rid of the parasite completely, most often one treatment is not enough.
Most insecticides available in stores help with the Scabbard.
Lepitocide is used for the moth.
Please note that it is highly not recommended to water the ground under the tree with drugs, unless otherwise indicated in the instructions.
Such actions can harm those who work or are simply in the garden.
Yellowing due to disease
These diseases cause the cedar to turn yellow:
- Rust. It is especially common in warm, humid weather that persists for a long time. The very first sign of the disease is the formation of yellow blisters on the needles. Later, they become covered with fungal spores, which look like a powder. The most vulnerable are cedars growing next to weeds like sow thistle or coltsfoot.
- Resin cancer (otherwise - seryanka). A fungal disease in which oval growths appear on the tree. By spring, they turn yellow due to plaque. If the integrity of the build-up is violated, spores are removed from it. Resin cancer reduces the cedar's immunity, making it vulnerable to insects. Those trees that grow near currants, mountain ash, gooseberries are in danger.
What to do
In case of cedar disease with pine needles or seryanka, the only way to fight is to remove the affected areas. The cut parts of the plant are necessarily burned so as not to provoke an epidemic.
Preventive measures
To prevent pests and prevent diseases, gardeners recommend performing several actions.
- Treat the trunk and crown using the hot fog method. This allows the insecticide to get into the deep layers of the bark, which will interfere with the further reproduction of bark beetles.
- Spraying the tree by hand. This procedure involves the treatment of the whole, since an unaffected tip or trunk can become a new focus of the disease or a place for the spread of remaining parasites. At the same time, insects develop immunity against the insecticide.
- Give cedar injections. The method reduces the frequency of spraying, but is ineffective against Hermes pine. The drug spreads with sap throughout the plant, making it poisonous to parasites. Even those insects that live in extremely hard-to-reach places are affected.
Cedar crisis. Special report by Alina Temnova
Thuja turned yellow? Do pine trees have yellow needles? Why do conifers turn yellow in autumn?
It is not always that the needles of a cedar turn yellow is a sign of a disease. Perhaps the tree is simply uncomfortable where it grows, or agricultural technology is violated.
So that the cedar does not turn yellow, it is necessary to provide it with suitable living conditions: regular watering and feeding, sufficient light and timely loosening of the soil.