Cultivating coniferous trees, gardeners often face problems with the loss of decorativeness, when the needles burn out, crumble and, as a result, die. Why does pine turn yellow and how to fix this problem?
Pine needles yellowing: causes and treatment
Natural causes
Slight yellowing of the needles on old shoots 3-4 years old is a natural phenomenon in the fall.
This is how the culture reacts to changing weather conditions - it partially becomes whitish or yellowish, sheds needles.
Pines also turn yellow after transplanting to a new habitat. Thus, the seedlings go through a stage of adaptation on the site, and after 1-2 months they are completely restored.
In the winter season, the tree can turn yellow from severe frosts. Usually young conifers, not insulated before wintering, are susceptible to this. Therefore, a month before the onset of cold weather, it is necessary to spud the near-trunk zone with peat, tie the twigs to the central conductor, wrap it in burlap or cover it with spruce branches.
If the color has changed in the spring, this is a sign of damping. Often, due to inexperience, gardeners cover the needles with dense material through which air does not penetrate.
As a result, the pines suffocate, and the needles on them begin to turn yellow en masse. The same reaction can be given by shoots that have frozen over the winter.
The summer phenomenon is caused by sunburn during crown sprinkling or foliar feeding at lunchtime. To avoid this problem, both procedures are performed in the evening.
Incorrect fit
Planting them correctly is an important step in the successful cultivation of pines.
Often, novice gardeners deepen seedlings into the soil along with the root collar. After a while, it begins to rot, and the needles on the crown turn yellow and crumble.
One simple rule must be observed - plant the plant so that the near-stem neck remains 5-6 cm higher than the soil surface.
The second moment that provokes such a phenomenon is landing in a swampy place. Ephedra does not like stagnant moisture.
There is a high probability of yellowing of pine trees growing in the open sun. The scorching rays burn out the tender and juicy needles, as a result, it looks like burnt, dries up and falls off.
Choose a shaded area with good access to daylight.
You can plant a pine next to tall trees with a wide spreading crown.
Density of plantings is another reason when pines turn yellow in a garden area. In crowded conditions, plants begin to compete for space, moisture and nutrients, the weakest change color, dry and crumble.
Depending on the variety, it is worth observing a certain distance between the seedlings, taking into account the dimensions of an adult tree.
Improper care
Only with proper care will the pine always be green
There are several reasons why the pines at their summer cottage dry, turn yellow and die.
Lack or excess of moisture
In the first and second cases, the needles turn yellow, the process of necrotization develops.
To eliminate the problem, it is necessary to adjust the irrigation scheme - for young plants, 10 liters of water is enough once a week, for adults - 40-50 liters three times per season.
This regime is valid in case of dry and hot summer. With frequent precipitation, moistening is carried out only as the soil dries to a depth of 6-7 cm.
Poor illumination
Due to the lack of sunlight, the needles begin to turn yellow, while the tree grows slowly and looks faded.
Plants growing in full shade should be transplanted to a well-sunlit area or, if possible, cut branches of closely growing and shading crops.
Air pollution
Growing near roads and gas-polluted places can lead to an undesirable process of yellowing of the needles.
Some varieties do not tolerate such an atmosphere, as a result, first the top turns yellow, then the whole crown. After that, the needles crumble.
Before buying, check with the seller if the tree can be planted in a contaminated area. Pine, which loves clean air, should be grown in a summer cottage away from dusty and gassed areas.
Lack or excess of fertilizer
Usually pines turn yellow when nitrogen is deficient.
Signs - slow growth and development, the needles acquire a chlorotic color.
The problem can be eliminated if you feed with nitrogen-containing preparations - nitroammophos or azofos at the rate of 30-40 g per 10 liters of water. Fertilize in early spring.
The color change of needles to yellow often occurs in plants with a lack of iron. The needles can be whitish.
To eliminate the problem, you need to feed with drugs in a chelated form - Quadris, Epin or Heteroauxin. They are used for foliar nutrition three times per season.
Pests
Yellow pest needles
If the pine has turned yellow, it may be due to an infection with harmful insects. This ephedra has several dangerous enemies.
Spider mite
A small insect braids with a thin cobweb the nodal parts, buds, young shoots and needles. The pest loves to feast on the juice of young organs, the affected tissues begin to turn yellow and die off.
In the fight and for prevention, acaricides are used - Actellik or Aktara. Remove damaged parts before spraying.
Aphid
This sucking insect settles in colonies and in a short period of time can destroy all the needles.
Affected buds, needles, young twigs turn yellow, dry and fall off.
- At an early stage of infection, folk remedies will help to cope with the pest: ash-soap solution, infusion of tobacco, garlic or hot pepper.
- At an advanced stage, it is necessary to use pesticides - Fundazol, Skor or Actellik.
Bark beetles
You can identify these parasites on pines by the numerous holes in the central conductor and skeletal branches.
A depleted plant begins to turn yellow, dry and die as a result. To fight, it is required to regularly dig the site in the fall in order to destroy the larvae wintering in the soil.
Additionally, trapping belts made of sticky materials are installed on the trunks.
Hermes
The larvae massively infect the needles, covering them with a white coating, later the needles turn yellow, dry and massively crumble. In the fight against these parasites, chemicals are used - Calypso, Confidor Maxi or Mospilan.
Red pine gall midge
A small dipteran insect can lay more than 100 eggs in one clutch, from which sucking larvae hatch. They gnaw the needles, which leads to their yellowing and drying out.
For the fight, several effective drugs are used - Engio, Aktaru, Mospilan or Calypso.
Mealybug
These pests damage, first of all, the root system, and later move to the aerial part.
In infected needles, the needles twist, acquire a yellowish tint. With a strong defeat, the shoots are covered with frost.
Folk remedies will help to get rid of insects at an early stage of infection - three times spraying with a solution of green soap with an interval of 7 days (10-15 g of substance per 1 liter of water). You can also spray the crown with tobacco infusion, garlic or cyclamen broth.
At the initial stage, only chemical preparations can cope - Tanrek, Confidant, Aktara, Mospilan, Calypso or Confidor. Spray twice at intervals of 10 days.
Shield
It is easy to identify pests - small reddish colored plaques stick to young shoots, needles, suck the juices out of them and lead to yellowing and drying out.
An effective drug Decis will help to get rid of the parasite. Irrigation of the crown is carried out twice with an interval of 5 days. Adults can be harvested by hand.
Diseases
In addition to harmful insects, yellowing of pines can provoke all sorts of diseases.
Rust
Fungal disease, the peak of which occurs during the hot summer season. Weakened specimens, as well as conifers growing in thickening, are most susceptible.
Signs of damage are the appearance of convex growths of a red or orange color on the surface of the trunk and skeletal branches. The diseased plant turns yellow, then throws off the young growth and needles.
At an early stage, you can cure:
- cut out all damaged organs;
- process the crown with a solution of copper sulfate, Bordeaux liquid or ready-made store preparations - Ridomil Gold, Tilt or Skor.
During the treatment of the fungal sore, watering should be reduced to a minimum. Sprayed in cloudy and dry weather to avoid burns.
Brown shute
The peak of the development of a fungal disease occurs at the beginning of summer.
The needles turn yellow at the tips, then turn yellow along the entire length, turn red and fall off en masse. At the end of August, numerous small black dots appear on the branches and needles - the sporulation of mushrooms.
The tree quickly dries up and dies, therefore, at the very first signs, high-quality treatment is necessary - remove all damaged organs, collect fallen needles under the crown.
Carry out three times treatment of pines and soil with a solution of copper sulfate, Bordeaux liquid or Ridomil Gold.
Preventive measures
Any problem is easier to prevent than to eliminate, so simple preventive measures will help you grow a strong and beautiful tree.
To do this, it is necessary to follow agrotechnical techniques, planting and care rules.
- Plant in a sunny place with little shade, where there is no swampiness and strong winds. When planting, it is important to avoid thickening and to use high quality and healthy seedlings.
- Adjust the watering regime to prevent drying out or waterlogging of the root system, and as a result, yellowing of the crown.
- Adhere to the frequency, scheme and dosage of fertilization - the first feeding is carried out in the second year after planting and only twice in the spring with nitrogenous, and in the fall with phosphorus-potassium. Additionally, the crown is irrigated with chelated products three times over the summer.
- Provide good access to light so that the needles fully develop and have a rich green color.
- Before wintering, insulate to protect against freezing in winter and damp off by spring.
- Regularly inspect for disease and pest infestation, and provide appropriate treatment if necessary. For prevention purposes, disinfectant treatments with fungicides and insecticides are carried out.