Yellowing of the sea buckthorn leaves compared to the original color becomes an alarming sign for the gardener. If in time to determine the cause of the disease, then the plant will be able to return to normal. Check out the factors that can cause the leaves of a plant to turn yellow and how to eliminate them.
Lack of nitrogen nutrition
Plants need nitrogen as an essential component of chlorophyll. Without it, the process of photosynthesis is impossible. If the sea buckthorn is deficient in nitrogen, then photosynthesis in the leaves slows down and they turn yellow.
A deficiency condition can occur even if there is enough nitrogen in the soil. Dry and cold weather on light and sandy loam soils makes it difficult for the plant to absorb nutrients.
If the weather conditions are normal, then you can replenish the nitrogen content during the growing season by introducing the following funds at the root:
- ammonium nitrate 20 g per 10 liters of water;
- urea 120 g per 10 liters of water.
Leaf top dressing with urea of 30 g per 10 liters of water will also help.
To prevent nitrogen deficiency in autumn, 100 g of urea is embedded in tree trunks to a depth of 7-8 cm. In spring, another 50 g of urea is buried under the same tree. In cases where compost or humus was introduced into the soil, the amount of urea is halved.
Diseases and the fight against them
Yellowing of sea buckthorn leaves may be associated with diseases. The task of the gardener is to quickly determine the disease and carry out therapeutic measures. If you promptly react to the manifestation of signs of a threat that has arisen, then it is often possible to safely overcome the dangerous state.
Scab
It is caused by a microscopic pathogenic fungus that infects leaf tissue, shoots and fruits. In the beginning, tuberous spots of yellow-brown color appear, which gradually blacken and become brilliant. The foliage dries up and turns yellow ahead of time, the fruits are mummified.
Diseased leaves and fruits are harvested and burned. If not treated, pathogens will overwinter in fallen leaves and mummified fruits. In the spring, in wet weather, the fungus will quickly spread again.
Control measures:
- Spray the sea buckthorn with a copper soap solution (8-10 g of copper sulfate + 2 tablespoons of a neutral type washing powder) per 10 liters of water. Treat at least 3 times every other day.
- Treat the plant with Avixil once (20-30 g per 10 l of water).
Verticill wilt (wilt)
A dangerous disease is caused by the fungus Verticillium dahliae, which clogs the conductive system of the sea buckthorn with its threads. This leads to the death of plants in one or two growing seasons. Fruiting specimens at the age of 5-8 years are more often susceptible.
In early August, on individual branches or on the entire tree, green leaves remain only on the tops of the shoots. The rest of the leaves turn yellow and fall off. The fruits are brightly colored, but do not pour, wither and wrinkle. Bulges appear on the bark, and then cracks.
What to do:
- remove the affected branches and burn;
- do not allow thickening of sea buckthorn;
- carry out preventive spraying with Bordeaux mixture in spring and autumn;
- spray in the summer with any modern remedies for fungal diseases.
If the treatment does not help, unfortunately the tree will have to be completely removed and burned. In the vacant place, it will be possible to plant sea buckthorn only after 5 years.
Fusarium wilting (fusarium)
This disease already in July-August causes yellowing of trees or individual branches entirely. It provokes earlier leaf fall, their drying and premature color of the fruit. The infected sea buckthorn plant dies the next season, not having time to recover.
Fusarium is one of the most common and dangerous plant diseases. Because of it, 10-20% of sea buckthorn trees, both seedlings and adults, die every year. It is almost impossible to cure a plant from fusarium.
There is only one method of fighting the disease - you need to immediately remove and burn the affected branches.
Agricultural techniques for disease prevention
Proper agricultural practices and disease prevention help protect sea buckthorn from various diseases.
What exactly needs to be considered when planting sea buckthorn in order to prevent diseases:
- Do not plant sea buckthorn in an area where strawberries used to grow, because these plants have the same type of disease.
- When planting yearlings place seedlings at a distance of 2 m from each other... In loose earth, make a shallow hole, pour a little mixture of humus and sand on its bottom, spread the roots of the plant on this hill, cover them with sand. Pour on top and add 10-12 cm of earth.
- Timely get rid of sick and broken branches.
- Fight the weeds, remove root shoots.
- Loosen the soil in near-trunk circles to a depth of 10 cm.
- Spend preventative spraying.
Pests and the fight against them
Sea buckthorn leaves can turn yellow under the influence of pests. Insects are functioning rapidly, and in order to notice the problem in time, one must observe the plantings daily.
Sea buckthorn aphid
It spreads especially strongly in moderately humid and warm years. Sea buckthorn aphid larvae winter on branches next to the buds. At the end of May, the larva turns into a wingless female founder, which gives rise to numerous offspring. They feed on the sap of young foliage.
Leaves turn yellow prematurely, curl up and fall off. The plant weakens and cannot prepare well for the winter.
Control measures:
- Take a decoction or infusion ash and tobacco, husks of onions, garlic, tops of tomatoes and potatoes, dandelion leaves. Add 30 g of laundry soap to 10 liters of water. Spray with the resulting composition.
- Spray with any modern insecticide. Use the dilution indicated on the packaging instructions.
Sea buckthorn sucker
Winged insect 3 mm long. In early August, the female lays spindle-shaped eggs in groups of 5-12 eggs. They hibernate in the buds of plants, and larvae emerge from the eggs during the budding period. With the appearance of leaves, the larvae move to their lower side and feed on the deciduous sap of the sea buckthorn.
Leaves turn yellow, wither and fall off.
Control measures:
- at the end of May, spray the crown with a solution of kalbofos 20-30 g per 10 liters of water;
- also in the spring, spray 100 g of colloidal sulfur in 10 liters of water.
Prevention
Regular preventive spraying is the most effective protection against pests. Insects, in the struggle for their existence, will definitely attack the plants in your garden, and the chemicals adhering to the tissues of the sea buckthorn make the living conditions on it unsuitable for parasites.
To prevent pests:
- spray sea buckthorn in late autumn and early spring with a Bordeaux mixture;
- spray the sea buckthorn with a solution of karbofos 30 g per 10 liters of water at the end of May;
- keep insecticides such as Confidor ready for treatment as soon as you notice pests.
If you notice that the leaves of sea buckthorn suddenly began to turn yellow, do not despair. The main thing is to determine the cause in time, then the plant, with a high probability, can be cured. And so that there is no need for future treatment, do not forget to carry out prevention and follow the rules of care.