Content
Boxwood, or buxus, as it is also called, is a very beautiful ornamental plant. It is quite unpretentious in care. But, at the same time, it is often exposed to various diseases and pests, which can lead to the death of the bush. If the appearance of the boxwood has changed, and its foliage has begun to dry out, turned yellow, or become covered with spots or holes, then it is necessary to find out the cause of this condition as soon as possible. To correctly identify boxwood diseases, photos and detailed descriptions of signs of infection will help gardeners take timely measures to save it.
Boxwood diseases and their treatment
Like many other ornamental plants, boxwood often suffers from various diseases. Most of them are fungal in nature and are caused by spores of a certain type of fungus. There are several main most common diseases.Below are the signs of various boxwood diseases, methods of treating them and photos.
White spotting of boxwood leaves
The disease has another name - septoria. The causative agent is many varieties of fungi of the genus Septoria. Light spots with a bright black edge grow on the leaves and shoots. The process continues with the proliferation of fungal spores, causing the leaves to turn brown. Boxwood becomes greatly weakened and vulnerable to other diseases and pests. Affected leaves fall prematurely, young shoots die, and bushes stop blooming.
The fight against the disease is carried out in 3 stages:
- Affected leaves and shoots are removed in such a way that the healthy part of the boxwood is captured when cutting.
- The resulting sections are disinfected.
- The plant is sprayed with fungicidal agents - Profit, Ridomit Gold or Bordeaux mixture.
Cool, wet weather promotes the spread of fungus through wind, rain, and insects. Spores of the fungal pathogen can survive for a long time in seeds, shoots and garden tools. To stop the activation of the fungus, it is necessary to destroy plant debris and disinfect all tools.
Dying of foliage and shoots
The disease manifests itself in spring, during the period of growth of shoots and young foliage. This occurs as a result of damage to the plant by the fungal pathogen Volutella buxi. The leafy tips of the shoots begin to change color. At first they become red, after a while - bronze, and at the end of the process - yellow. Branches affected by the disease die. If diseased shoots are cut, peeling bark and circles of dark color will become visible, alternating with colorless wood.Leaves and stems become covered with a pink coating in humid weather.
The fungus is almost impossible to remove. It is resistant to various chemicals designed to combat such pathogens. Boxwood can only be saved if damaged stems are removed. To do this, they are cut off, and the fallen leaves are collected and taken outside the site. In case of severe damage to the entire boxwood bush, you can resort to the help of fungicidal agents that contain copper.
Dropping leaves
This is a more serious and dangerous leaf shedding fungus that invades new surfaces with amazing speed. The foliage, and behind it the young shoots, die and fall off. At the same time, oblong spots of a dark shade first appear on the shoots.
The disease becomes more active mainly in the summer, in bad weather conditions. As a result of the disease, boxwood may completely or partially die. In order to combat the pathogen, it is necessary to destroy all infected leaves and branches, including those that have already fallen. To carry out preventive protective measures, bushes are treated with fungicides before the onset of bad weather. The photo shows the successive stages of boxwood disease.
Rust
It is transmitted by air by spores of the fungus Gymnosporangium sabinae. When infected, brown pads appear on the upper and lower surfaces of the leaves. Affected foliage should be collected. The plant must be treated with Agipa-Pic, Topah or Bordeaux mixture.
Fungal spores infect pear leaves and can fly very far. Therefore, both plants should not be planted next to each other. Affected boxwood shoots must be carefully trimmed and removed.
Rot of the stem base
White rot is the most severe disease of boxwood, which can develop very quickly and is characterized by the following symptoms. The top of the bush withers, the lower part of the stem rots. The leaves lose color and become watery. A white coating may form. Large black growths appear on the surface of the stem - fungal sclerotia. They can also be seen in a section of the shoot.
The pathogen enters the plant from the soil through the lower part of the stems. The disease is especially active in conditions of high air humidity, at low temperatures of 12 – 15 °C. Fungal spores spread with the wind.
To strengthen the plant and prevent its infection, it is recommended to use foliar fertilizers:
- urea – 10 g;
- copper sulfate – 2 g;
- zinc sulfate – 2 g.
All components should be dissolved in 10 liters of water.
Cytosporosis or decaying burn of boxwood
This is a very dangerous infectious disease of the plant bark. The affected areas become dry and begin to crack at the border with healthy ones. The bark is covered with a large number of dark tubercles containing the fungus that causes the disease. Damaged areas take on the appearance of “goose bumps”. Leaves and flowers dry out, but do not fall off for a long time.
If the fungus penetrates into the deeper layers of the tree, gum flows out of the resulting cracks, the hardening of which leads to disruption of the conductivity of the boxwood vessels. The infection enters the plant through any violation of the integrity of the bark, regardless of the nature of its origin - wounds, cuts, scratches, cracks. The death of the branches occurs after 1 - 2 months. Gradually multiplying, the fungus covers an increasingly larger area of the bush and, getting into the wood, can lead to the death of the entire plant.
In the early stages of the disease, before the fungus has gone deep into the bark, it is removed with a knife, leaving only healthy tissue. The remaining wounds are disinfected with 2% copper sulfate and covered with nigrolic putty or garden pitch. It is recommended to additionally bandage very large wounds.
Root rotting
This destructive process and many other painful conditions of boxwood can be caused not only by fungal pathogens and improper care. The ornamental plant does not like excessive soil moisture. Frequent watering, especially during cold periods, leads to the root system suffocating, overcooling and rotting. The plant ceases to receive the required amount of moisture and nutrients and, ultimately, dries out.
To prevent the occurrence of such a disease, watering boxwood must be reduced in autumn and winter.
Boxwood pests and their control
In addition to the listed diseases, various boxwood pests that attack the plant cause a lot of trouble and trouble for gardeners. How to deal with them depends on their type and the degree of harm caused. The most common boxwood insects are:
Boxwood gall midge
When attacking a boxwood, this mosquito-like parasite creates growths that hide inside orange larvae no larger than 2.5 mm in size. Noticeable convex yellow spots with swollen nodules at the bottom appear on the leaves. The affected plant very quickly turns yellow and dies.
At the first symptoms of the appearance of gall midges, boxwoods are treated with Bitoxibacellin, Fufanon, Molniya, Actellik, Karbofos-500.Treatment is carried out 2-3 times a week, from the second half of May to mid-June, during the appearance of insects from pupae.
Leaf flea (psyllid)
This small yellow insect infects the leaves, causing them to swell, curl, curve in the shape of a spoon and become covered with a white coating. The sticky secretions of fleas form a waxy coating under which the larvae live. Pests feed on boxwood sap.
These insects can be controlled using insecticides. The affected foliage is removed, and the boxwood is sprayed with mineral oil. In most cases, the damage caused by these psyllids does not cause significant harm to boxwood bushes.
Spider mite
Spider mites are most common in areas characterized by warm climates. It actively shows its effect in conditions of high temperature and dry air. Small insects no larger than 0.5 mm in size settle on the underside of leaves. Boxwood branches are entangled in cobwebs. As a result of punctures by mites, the leaves first become covered with small yellow specks, then become discolored and die. Boxwood is losing its strength.
Spraying with chemicals such as Fufanon or Actellik will help get rid of a large number of ticks. If there are few insects, they can be washed off with a soapy liquid prepared from 120 g of laundry soap and 4 liters of warm water. Then the boxwood should be treated with an oil spray.
Boxwood felt weed
The sucking insects, called hair lice, are visible to the naked eye. They form whitish secretions on the veins and cuttings of leaves, similar to waxy traces, in which colonies of these pests develop.Scale insects lay numerous eggs, wrapped in felt-like bags, on the underside of leaves. The period of active development occurs in June and the second half of August. Boxwood foliage turns yellow and falls off. If timely protective measures are not taken, the death of the plant occurs after 2–3 years.
In order to combat felt weeds, first of all, it is necessary to remove damaged branches and leaves of boxwood. The bushes are sprayed with mineral oils, which form an oil film. Insects suffocate under it and die. You can also treat boxwood with methyl bromide.
Boxwood moth
The moth causes significant harm to boxwood. Lime-green caterpillars envelop the entire tree in a thick web and feed on its leaf pulp. The leaves change their color. The bushes dry out quickly, which is accompanied by an unpleasant odor.
Boxwood is sprayed with biological insecticides, depending on the level of development of the larvae. Not only the plant itself is treated, but also the soil around it within a radius of 40 - 50 cm. In the fight against boxwood moth, drugs such as Bi-58, Decis, Fastak, Shar Pei, Vega, Atom, Fury have proven themselves well. These potent agents should be used with extreme caution. In the early stages of the disease, it is better to use the insecticide Dimilin, which is safe for people and animals.
Scale insects (false scale insects)
Insects that look like white and golden-brown tubercles live on the surface of boxwood stems. Microscopic pests can often be picked off with a regular needle. You can also remove them with an old toothbrush. This method is completely safe for boxwood.
After treatment, the stems are wiped with kerosene using a piece of cotton wool.The resulting kerosene film causes insects to suffocate and die. Spraying boxwood with an oil spray will restore the lost shine to the leaves. If there are a significant number of pests or if a large number of boxwood bushes are infected, it is better to treat the plantings with insecticides.
Gall (four-legged) mite
When attacked by a pest, the buds and growing leaves of boxwood are damaged. Pubescent elongated growths appear on them - galls, which creates the impression of their swelling. Although mites rarely cause significant damage to boxwood, they are quite difficult to control.
Treating the effects of diseases and pests on the growth and health of boxwood takes quite a long time and requires some knowledge and skills. To prevent this, regular implementation of certain preventive measures is recommended.
Prevention of diseases and pests of boxwood
Under the influence of pest attacks and the negative manifestations of various diseases, a beautiful ornamental boxwood plant can very quickly lose its strength and subsequently die. Timely implementation of certain preventive measures will help avoid such severe consequences.
The main measures to prevent the occurrence and development of boxwood diseases include:
- proper care - fertilizing, pruning, treatment with drugs;
- disinfection of instruments;
- removal of damaged parts of the plant;
- maintaining stable temperature and humidity levels when growing decorative boxwood indoors.
Often the cause of plant diseases is simple non-compliance with the rules of care and growth. A change in the appearance of the bushes may indicate the following:
- Drying and curling of leaves due to lack of moisture. Boxwood should be watered more often and abundantly.
- Loss of green color intensity in foliage - in case of excess sunlight. It is necessary to create shade conditions.
- The appearance of yellowness indicates a change in low temperatures. The plant needs additional heating.
- The leaves acquire a reddish hue when there is insufficient nitrogen supply. Boxwood bushes should be fertilized regularly.
In the fight against pests and diseases of boxwood, you can take advantage of the influence of their natural opponents. Insects such as ladybugs, earwigs, predatory mites, hoverflies, lacewings and others eat aphids and fungal spores. To attract these helpers to the garden, you should sow dill, mustard, phacelia, parsley, cilantro, cumin, and plantain.
Compliance with the basic rules of care and the creation of favorable conditions for the growth and development of boxwood are the best means of prevention against diseases and pests.
Conclusion
Having studied boxwood diseases, photos of pests and ways to combat them, you can safely acquire this wonderful ornamental plant on your site. With proper care and original formation of the crown, it will make an unforgettable impression and delight the owners and guests of the garden plot with its appearance.
Healthy. But why does a white border appear along the edges of almost all leaves? The bush was planted in May. Rostov region.