Cedar is a fairly common crop that is often used in landscape design. This is due to the high decorative properties of this plant. For the cultivation of a crop to be successful, it needs to be provided with quality care. However, sometimes the tree changes its color. In this case, the question arises, what to do if the cedar needles turn yellow.
Causes of yellowing
Cedar is characterized by rather slow growth. A 5-year-old seedling reaches a height of 25-35 centimeters, and by 10 years it grows to a maximum of 1.5 meters.An adult crop can grow by 35 centimeters per year. This period begins at 15-20 years.
Mature plants usually do not cause problems, while young seedlings require proper care. If the rules of agricultural technology are violated, the tree loses its decorative effect and may even die. This is why it is so important to strictly follow the rules of agricultural technology.
If yellowness appears on the old branches by autumn, there is no need to worry. This process is considered completely normal. At the same time, the young shoots remain green. If more than half of the crown turns yellow, you need to assess the condition of the tree. The main causes of problems include the following:
- Pest infestation. Yellow needles are considered the first sign of a deficiency of useful elements in a tree, as they are absorbed by parasites.
- Young age. At the initial stage of development, cedar cannot boast of strong immunity. Therefore, it exhibits high sensitivity to changes in living conditions and is considered susceptible to parasites and diseases.
- Stress. Problems are most often associated with unfavorable weather conditions or appear during transplantation.
- Incorrect care. Problems are caused by excess or lack of moisture, deficiency of useful elements, and drought.
The main cause of yellowing of needles is still considered to be attacks by parasites. At the same time, other manifestations of problems appear - in particular, streaks of resin on the bark and brown flour. These signs indicate bark beetle activity. As a result, there is a risk of the tree drying out. To save the culture, intrastem injections are required.
If there are a large number of white dots on young shoots, one can judge the activity of Hermes. If green branches are covered with a mass of caterpillars, this indicates a pine moth infestation.When a gray coating forms on young shoots, an aphid attack can be suspected. All this provokes yellowing and falling of the needles. In this case, the tree needs to be saved.
Pest Control
If the yellowing of the crop is caused by insect attacks, this can lead to its death. That’s why it’s so important to take action in a timely manner. To do this, you need to spray the cedar or pour the solution under the root.
Hermes
This is a small pest that is a type of aphid. It attacks coniferous plants and absorbs their juices. These pests can be difficult to spot. However, signs of attacks can be seen. When cedar is damaged, the needles and young branches become covered with white dots. They are Hermes larvae. At the same time, adult insects are distinguished by a brown tint.
In winter, insects are in the larval stage. They absorb tree sap. As a result, the needles become yellow and may fall off. To destroy parasites, you need to remove branches with white coating and spray the shoots with an insecticide solution 1-2 times a month.
In simple cases, the tree can cope with pests on its own. If a young crop is severely damaged by pests, it needs help. To do this, use the following means:
- "Aktara" is an effective product that provides excellent protection against insects. To use the drug, you need to mix 3 grams of the substance with 10 liters of water and water the tree in the circle around the trunk.
- "Actellik" is a powerful insecticide that affects various parasites. To prepare the working fluid, combine 10 milliliters of the product with 10 liters of water. The composition is used for spraying plantings. The procedure is carried out only in calm weather. Treatment of plantings leads to the immediate death of parasites.
When processing crops, you should use personal protective equipment. To do this, wear glasses, gloves, and a respirator. The duration of operation should be a maximum of 3 hours.
Shchitovka
If the cedar has turned yellow, you can suspect an attack by scale insects. They are white-brown insects that settle at the base of needles on young shoots. Parasites are usually noticed when the needles fall off. It can be difficult to cope with these pests, since they are attached to hard-to-reach places and are immobile. In addition, parasites are reliably protected by a wax shield.
Therefore, it is recommended to use soil-based agents to destroy pests. Thanks to this, the plant becomes toxic to scale insects for a couple of months. Effective insecticides include “Antikhrushch” and “Aktara”.
To prepare a working solution from Antikhrushch, you need to take 10 milliliters of the substance in a bucket of water. When using Aktara, 3-5 grams of the substance are mixed with 10 liters of water. For 1 meter of trunk it is required to use 10 liters of working solution.
Products can also be applied by spraying, but they will not be as effective. Actellik is a good choice for this purpose.It is a fairly powerful systemic insecticide. To prepare the working fluid for 10 liters of water, you need to take 10 milliliters of the drug. The resulting product should be sprayed onto all parts of the plant. This must be done in calm weather.
Moth
The pine moth often lays eggs on cedar trees. This occurs from the end of May to the end of July. In this case, the female chooses old needles for laying. It takes approximately 20 days for the larvae to develop. In August, young shoots are attacked by many caterpillars. As a result, the tree turns yellow and dries out. A small plant may even die.
To cope with the moth, you need to use the drug “Decis Profi”. It is an insecticide that has a contact-intestinal effect. To use the substance, you need to mix 2 grams of the substance with 10 liters of water and apply it to the tree in an even layer. The advantage of the product is that it begins to act within a few hours after use.
Aphid
This pest is a small, hairy insect that is gray in color and has an elongated body. These parasites prefer to settle on new shoots and absorb plant juices. To cope with the pest, it is recommended to spray the tree with a solution of karbofos. This needs to be done several times. To prepare the working fluid, you need to mix 90 grams of the substance with 10 liters of water.
It is also permissible to use Fufanon. This universal remedy protects plants from many parasites. In this case, you need to mix 10 milliliters of the substance with 10 liters of water and spray the plantings in the morning or evening. It is important to wet the needles well, but not to allow the composition to get into the ground.
How to care for a sick tree
Cedar develops best in well-lit areas. However, it is recommended to shade young plants to avoid yellowing. It is important to consider that the culture is considered to be very moisture-loving. In summer, the tree absorbs a lot of moisture, so during drought it needs to be watered systematically.
Depending on the height of the trunk and weather conditions, it is recommended to adhere to the following rules:
- for crops up to 10 meters, use 90-400 liters per week;
- for trees up to 5 meters, use 35-150 liters per week;
- for cedars up to 3 meters, use 20-80 liters per week;
- for plants up to 1 meter, use 5-20 liters per week.
At the stage of preparing the crop for winter, watering must be abandoned. Stagnation of moisture and excessive waterlogging can lead to the death of the plant.
When growing cedar, it is important to consider that this crop loves acidic soil. Therefore, the soil reaction needs to be checked. If the substrate does not meet the requirements, the tree trunk circle is watered with a solution of citric acid. To prepare it you need to take 20 grams of the substance per 10 liters of water. After 3 months the tree will recover.
It is recommended to use azofoska to feed cedar. This combined mineral fertilizer increases the crop's resistance to disease and improves its growth. To do this, you need to use 40 grams of the product per 1 meter of tree trunk circle.
The drug “Eco-1” is also considered an effective substance. It improves the growth of culture and ensures its full development. This is achieved due to the increased content of useful elements in the product. In addition, the composition strengthens the culture’s immunity. To prepare the working fluid, it is recommended to take 10 grams of the substance per 1 bucket of water. This solution should be applied at the root. This dosage is suitable for crops above 1 meter.
If a crop is damaged by parasites, it is recommended to reduce the amount of nitrogen in fertilizers. In this case, it is permissible to use liquid substances “Master” or “Activin”. To increase the protective properties of the crop, it is worth using the preparations “Viva” or “Kendal”.
Trimming
It is recommended to prune conifers at the stage of active shoot development. Therefore, when a small number of parasites appear on the branches, they need to be removed and burned. If the damage is significant, you should use chemicals.
Pest prevention
To avoid crop damage by parasites, you must adhere to the following rules:
- Treat the trunk and crown using the hot fog method. This will help the insecticide penetrate the deep structures of the bark, which will prevent the subsequent proliferation of bark beetles.
- Spray the tree by hand. This procedure involves complete processing of the culture. If certain areas are missed, they can become a new source of problems.
- Inject into the cortex. This method helps reduce the frequency of spraying. The drug spreads throughout the crop, making it toxic to pests.
Yellowing of cedar needles may be due to the influence of various factors. However, the most common cause is parasite attacks. That is why it is so important to treat the plant with insecticidal preparations in a timely manner.
