Diseases and pests of conifers - prevention and control measures
Coniferous plants are a spectacular decoration of our gardens. Sooner or later, we all strive to realize interesting ideas of landscape design with the help of various spruces, pines, junipers and other conifers. These plants are considered hardy and quite resistant to disease, but, unfortunately, they also get sick and are affected by pests, especially in the first years of life. We will talk about prevention and measures to combat diseases and pests of conifers in this material.
Prevention of diseases of conifers
As doctors often tell us, any disease is easier to prevent than to treat. This promise applies to all living things and to conifers, including. Therefore, prevention cannot be neglected. And it starts from the moment you select a seedling.
Preventive measures that are necessary for conifers:
- When purchasing a seedling (it does not matter when buying in a store, in a bazaar, in a nursery, or digging in the forest), first of all, you need to assess the condition of the needles and branches. The shoots and the trunk should not have an affected bark and smudges of resin, and the needles just have to be clean - without dried and yellowed areas, without plaque and spots. If the plant is bought at a sale - with obvious defects, but cheap - it will require treatment and quarantine. Such a specimen cannot be immediately planted in healthy plants.
- Even if you brought a healthy, at first glance, seedling into your garden, spray it with fungicide to prevent it from planting. The fact is that many diseases have a long incubation period and the disease does not appear immediately.
- Inspect your young conifers regularly. This is the only way to detect signs of the disease or pests on time. After all, the sooner the problem is discovered, the easier it is to cope with it, and the more chances a plant does not die.
- Healthy, well-groomed trees are less susceptible to attacks of various diseases and pests and are easier to cope with such troubles. Therefore, proper fit and care play a decisive role in disease prevention.
Mandatory but uncomplicated care measures that you will present to your coniferous health when completed:
- timely watering;
- introduction of seasonally appropriate root and foliar top dressing;
- removal of broken or damaged branches;
- preparation for wintering.
Read about the rules for preparing conifers for winter in the article “7 conditions for successful wintering of conifers”.
How to increase the immunity of conifers?
A deficiency of essential trace elements negatively affects not only the appearance of the plant, its general condition, development, but also its ability to cope with various diseases. Conifers suffer from insufficient receipt of the necessary elements as follows:
- lack of nitrogen - grow poorly and have a pale color needles;
- iron deficiency - turn yellow, and sometimes turn white;
- phosphorus deficiency - blush.
To increase the immunity of coniferous plants, it is necessary to apply fertilizers and, best of all, special ones for conifers. The fact is that the usual mineral dressings sold in stores are intended for fruit and berry crops, and application rates are calculated specifically for these plants. Conifers have other needs, and the norms for them are much lower.
When applying fertilizers, it is best to alternate root dressings with foliar, which are often forgotten. But just through the leaf (and the needles are the leaves) the plant better absorbs many trace elements.
Do not forget that fertilizers containing nitrogen are applied only until mid-summer, as this element causes the growth of shoots. From the second half of summer, you can feed phosphorus-potassium fertilizers with other trace elements, excluding nitrogen - they will help the shoots to mature, and the plant will successfully survive the winter.
Such preparations as Zircon, Super Humisol, Immunocytophyt, Epin-Extra, Nikfan will help improve absorption and normalize the balance of trace elements. These biological products also improve root formation, increase the immunity and resistance of plants to various stresses - bad weather, attacks of pests and diseases.
The main diseases of conifers
Signs of disease can be found with regular inspections of plants. Yellowed or dried up needles, dried branches, bald patches and an unkempt appearance indicate a problem that has arisen, regardless of whether it is a pine or juniper, thuja or spruce.
Fungal disease causing early decay of pine needles. Most often, young or weak pines fall ill. You can determine the disease in spring or early summer - the needles turn brown and crumble. When viewed on pine needles, you can see small yellow dots that grow, taking on a brown color. Apothecia, the fruiting bodies of the fungus, are formed on the fallen affected needles. With a large loss of needles, the plant may die.
In terms of distribution and symptoms, it is similar to shute real. With this disease, the pine needles turn yellow or turn red-brown, and black dot fungi appear on the needles. The needles eventually die and fall.
The conditions suitable for the development of these diseases are formed in the warm season, with fogs and dews, as well as during prolonged drizzling rains.
Like other types of this disease, snow shute most often affects pine trees. This formidable disease can completely destroy the young planting and self-sowing of pines. Mycelium of the fungus, growing, captures the neighboring areas of needles, and the resulting spores are carried by air currents. Mycelium is able to grow and develop in the cold and even under snow cover. The needles at the beginning of the disease become bright red, then turn gray and begin to crumble.
The development and spread of snow shyutte is facilitated by a protracted autumn with frequent rains, snowfalls and snowmelt; mild winter with thaws, as well as long, prolonged rains in spring.
Prevention and treatment of shute
Since all types of shute prefer damp, the main preventive measures will be:
- Proper landing - without thickening, with good ventilation and lighting, in places that exclude stagnation of water;
- Increased plant immunity;
- Timely removal of affected parts of plants;
- If there is a risk of a disease - a single spray with copper-based preparations - “Hom”, “Bordeaux mixture”, 1% solution of copper sulfate (100 g of powder is diluted in 10 l of water, heated to 45-50aboutFROM);
- Ill plants are sprayed with preparations - Skor, Chistotsvet, Strobi, but several treatments are used for treatment (the method of preparation of the solution and the number of treatments are indicated in the instructions for the preparations);
- After processing, it is necessary to remove all dead needles and burn.
One of the most common diseases of conifers is rust. There are several varieties of this fungus, but all of them are considered to be “heterogeneous”, that is, they affect not only coniferous, but also fruit crops, and therefore can be transmitted from one to the other.
Pine rust cause several types of fungi at once. They develop in the spring, forming yellow vesicles on the needles. When a disease occurs, the needles turn yellow and crumble, and the tree loses its decorativeness and becomes depressed. Spores of pathogenic fungi are formed on herbaceous plants - thistle, coltsfoot, bluebells, etc.
Bubble and columnar rust, as well as pine sprat excites a diverse mushroom kronartium ribikola. In infected trees, the needles are first affected, then the fungus sneaks into the bark and wood. Young infected seedlings bend into an ugly shape, and bark may crack in adult plants. Resin emerges from the cracks, interspersed with yellow or orange bubbles. At the site of the mycelium, the bark thickens, and the overlying shoot gradually dries out and dies. This mushroom also affects gooseberries and currants, drying and twisting their leaves.
Juniper rust can affect not only conifers, but also hawthorn, pear, apple tree and cotoneaster. On fruit plants, the disease manifests itself in the spring in the form of yellowish growths on the underside of the leaf, at the same time, orange spots with black dots appear on the top. On the needles and shoots of juniper, you can see yellow jelly-like masses of pathogenic fungus spores. The shoots of the affected plant swell at the site of settlement of the mycelium and take the form of a spindle.
In the spring, examining junipers and arborvitae, it is necessary to push the branches apart, since many varieties have a rather dense crown. Outside, there may be no signs of the disease, and inside, closer to the trunk, areas of damaged needles are easily detected.
In the case of horizontal junipers, in preparation for winter, it is necessary to raise the lower branches and place stones or bricks under them. This measure will save them from a long stay in cold water in rainy autumn and with spring snow melting, thereby possibly saving them from the onset of the disease.
Coniferous rust prevention and control
To prevent the occurrence and spread of rust, we can recommend the separate cultivation of conifers and other ornamental and fruit crops suffering from the same diseases. So, it is recommended to plant pines away from poplars, aspen and currants, and juniper should not be adjacent to a pear, quince, apple tree, cotoneaster and hawthorn.
The rest of the preventive and treatment measures are the same as those described above, with schute diseases.
Resin cancer, or pine seryanka (silverfish)
It is manifested by peeling and flaking of the cortex at the lesion sites. Resin, emerging from wounds, forms large cracked growths. It is impossible to cure such cancer, but infected trees can live for decades, although they will lag behind in growth.
If a diseased tree grows on a site near other woody plants, it is better to remove it to prevent the spread of the disease. If it is impossible to remove the diseased specimen, it is necessary to cut off the diseased branches, and clean the wounds on the trunk as much as possible, treat with a solution of copper sulfate or Bordeaux mixture and cover all the cleaned places and saw cuts with garden putty.
The same measures apply in the event of other types of cancer - rust fir cancer, larch cancer, pine and spruce cancer, shoot cancer.
One of the most formidable diseases for representatives of conifers. The causative agents of the pathogenic fungus are in the ground, so the defeat of the plant begins with its roots. Introducing into the peripheral roots, the fungus, gradually advancing, enters the vessels and, growing, fills other parts of the plant with mycelium. By isolating toxins and depriving the roots of the ability to supply the tree with nutrients, the fungus causes irreparable harm to the plant.
The danger of this disease is that the first signs appear when the disease has already affected the root system. The needles turn yellow and fall, and the tree itself dries out slowly. The treatment of fusarium is complex and lengthy because of the inability to start it at an early stage, therefore it rarely leads to healing. Often spraying the crown with fungicides and pickling the soil does not lead to the desired result, and the diseased plant must be removed.
In order to prevent the appearance of fusarium on your site, you need to carry out preventive measures:
- Before planting, soak the roots of the seedling in the Fitosporin-M solution for 2-3 hours or pickle with Trichodermin.
- When planting a seedling on the bottom of the planting pit, lay broken brick, expanded clay or crushed stone. Such drainage will relieve accumulation and stagnation of water and protect the plant from many troubles.
- To prevent thickening of plantings - all plants should receive enough light and be well ventilated, so be sure to maintain the recommended distance between the trees.
- Loosening the soil and removing weeds is not a trifle, but important measures to prevent the appearance of diseases.
- Do not forget that phosphorus-potassium top dressing increases the immunity of plants to fungal infections.
There is an interesting way to detect the presence of mushrooms "by smell." For this, a small portion of the earth is taken from under the investigated tree and sniffed. If there is a smell of pretty foliage and mushrooms, it's probably time to start treatment.
It is characterized by tarnishing and decay of the needles. Slices of branches in this disease are clean, there are no dark rings or spots on them, as with Fusarium, and treatment that is started early will often lead to success.
For treatment, the soil around the diseased tree is shed with a solution of Fundazolum, and after three days - Fitosporin-M. Then after 2-3 days you should water the tree with a solution of "Zircon" or "Epin-extra." After two weeks, you can repeat the cycle. Fundazole can be replaced with Kartotsid, a versatile and highly effective bactericidal antiseptic.
Sunburns on conifers are fairly easy to distinguish from other diseases. They appear, as a rule, in the early spring from the sunny side. The needles in these places turn yellow, and the tips of the branches dry. With large areas of burns, a tree or shrub lose their decorative appearance, since dried branches will have to be cut.
To protect your conifers from the spring sun, it is necessary to cover plants with a special mesh or any breathable material from autumn. If for some reason the shelter is not used, then in early spring you can sprinkle snow around coniferous lands, ash or peat. After all, burns are the result of increased reflection of sunlight from snow.
Pests of conifers
Conifers are no less susceptible to attack by harmful insects than fruit or ornamental crops. Some of them feed on needles, others sharpen wood, but all of them bring undeniable harm to the plant. It is possible and necessary to fight them, but in order to win in this battle, you need to know the enemy in person. In most cases, the pest can be determined by the nature of the lesions on the plant.
Bark beetles are small inconspicuous bugs, no larger than 12 mm in size. Pests make moves under the bark, often reaching wood. Females in the passages lay their eggs, and the hatched larvae continue their dirty work, creating real labyrinths of passages. At the end of each turn, they settle in and pupate. Beetles resulting from this metamorphosis make holes in the cortex and fly out. It is from such holes that you can determine the pest.
It is difficult to fight the bark beetle, but given that it usually settles on diseased and weakened trees, efforts must be made to maintain the overall healthy state of the plants and increase their immunity.
To fight using pheromone traps. They are attached to the trunk, and beetles fly into them from a fairly large distance. Antipheromones are also used, but already to repel the pest. Also used are insecticides in the form of sprayings - “Clipper”, “Bifentrin”, “Krona-Antip” and others. In the absence of a positive result, you have to say goodbye to a tree.
The spider mite is omnivorous and affects almost all cultivated plants. Small insects (they can not always be seen with the naked eye) suck the juice from the leaves of plants, leaving small bright spots on the surface. A spider mite can be detected by a thin web covering needles.
A spider mite appears and actively multiplies in dry warm weather, therefore it is very important to maintain air humidity. For this, plants are often sprayed with ordinary water, in drought every day.
To combat spider mites, acaricides - Envidor, Flumayt, Apollo or insectoacaricides - Actelik, Akarin, Fitoverm are used. Preparations are bred with water, according to the instructions, and sprayed on plants in dry cloudy weather or in the evening. The frequency and frequency of repeated treatments can also be found in the instructions.
Spruce trees of all varieties are favorite pine conifers, but some types of pines - mountain, ordinary, cedar and Weimutov pine can also suffer from this pest.
Larvae of sawflies look like caterpillars and act also - from May to June young growths of conifers gobble up, after which the branches dry out and die.
It is not difficult to get rid of the sawfly, the main thing is to notice the enemy in time. For spraying plants, you can use any insecticides for a complex of pests.
Scaffolds and false shields
Sometimes on the leaves of plants you can see small brown or yellowish growths in the form of a plaque. If the growth is flat - this is a scab, if convex - a false scab. Larvae of both of them parasitize all year round, drawing juice from plants and thereby causing great harm. The plant affected by the scabies grows worse, its needles turn yellow and crumble.
The needles, struck by a false scutellum, grow dull and are often covered with a sticky coating, which wasps love so much. It was the appearance of wasps that should alert in the first place, if other signs went unnoticed.
To combat scabies and false shields, 2-3 treatments are carried out with systemic insecticides - Confidor, Aktara, Bankol and Aktarlik or Fitoverm acaricides. These pests are well protected from external influences by shields, therefore the preparations should be contact-intestinal (systemic). When processing, it is desirable to alternate drugs from the first and second groups.
Pine and spruce are Hermes's favorite treat. There are several groups of these pests, which, replacing each other, parasitize from spring to autumn. All of them form galls on the shoots, which differ in appearance. So, at the beginning of summer, oval small galls can be observed on the needles of plants, in August - green, rather large, and from late August to September - large spherical galls. Hermes females draw juice from plants, and the larvae damage the kidneys.
To combat hermes, you can use the same means as against shields, since they also have protection against external influences, only these are not shields, but a dense, downy cover. Therefore, systemic insecticides will be used.
Conclusion Conifers, like any other plant, are susceptible to various diseases and damage by pests. Many of them are difficult to treat, especially if it is an adult tree, and some - and, in general, impossible. Therefore, preventive measures play a major role in maintaining plant health.
And there are no trifles - proper planting, care and regular inspection of plants will help, if not prevent, then find the problem in time and start treatment. With this approach, the chances of saving a tree increase significantly.