Content
Juniper is a popular crop in landscape design and is widely used for gardening and urban landscaping. There are more than a hundred species and varieties of this evergreen plant - trees of various shapes and sizes, medium-sized, dwarf and creeping shrubs. Junipers go well with deciduous trees and flower beds; they can be used to create various compositions. Undemanding to care and soil composition, they can be affected by pathogenic microflora and parasites. How to identify plant diseases and harmful insects, what drugs to treat the plant for treatment and prevention will be discussed further.
Juniper diseases and their treatment
Juniper is rarely damaged by diseases and pests. This is a strong plant that is not afraid of unfavorable climatic conditions. Juniper is most susceptible to infection by diseases and pests in the spring, before warm weather sets in. At this time, the juniper is harmed by sudden changes in temperature, which causes frostbite of the roots or burns and drying out of the crown.The crop does not easily tolerate stagnation of moisture in the roots that forms after snow melts, or, on the contrary, long-term drought after a snowless winter. As a result, the juniper's immunity weakens and it becomes defenseless against various pathogens. Immature young plants are also susceptible to infection. It is very difficult to visually diagnose juniper diseases; common symptoms for them are yellowing, browning and dying of needles, drying out of branches, and thinning of the crown. The following will provide an overview of the most common juniper diseases with photos and recommendations for their treatment.
Rust
Juniperus rust disease is caused by the fungus Gymnosporangium, which requires two host plants for its full life cycle. Juniper is a winter host, Rosaceae (apple, pear, quince) are summer hosts. The fungus lives on branches, trunks, needles and cones, causing branches to die and bark to dry out and crack. The disease manifests itself in the spring: brown formations form in the wounds of the plant, which after rain or dew swell and become covered with mucus. Spores germinate from them, forming an orange coating. The wind carries them to fruit trees. They parasitize on the leaves, form growths on which spores mature, which subsequently infect the juniper. Infection occurs within a radius of 6 km.
To control the disease you should:
- prune infected branches in early spring and winter;
- do not plant both host plants next to each other;
- treat juniper from rust with Arcerida solution, Bordeaux mixture.
Favorable conditions for the spread of the disease are dampness and coolness.During periods of prolonged rain, you should regularly inspect the juniper. Having discovered orange growths on the above-ground parts of the plant, you need to rush to treat it.
Juniper rust disease is shown in the photo:
Cortical necrosis
This juniper disease is also called nectriosis or nectria canker. The causative agent, the fungus Netctriacucurbitula, penetrates into a wound on a tree resulting from mechanical damage to the bark. The disease is manifested by the formation of local and ring necrosis of branches and trunks without changing color. In spring, brick-red, convex, smooth pads up to 2 mm in diameter appear in cracks in the bark. These are stroma - plexuses of mycelium, on the surface of which spores develop. Over time, they turn black and dry out. Subsequently, the needles begin to turn yellow, the bark is torn off, the branch dies, and the juniper dies. To prevent the development of the disease on the plant, you need to take measures:
- remove diseased branches;
- thin out thickened plantings;
- treat with a copper-containing preparation.
When destroying a plant, it is important to thoroughly clean the soil of plant debris and treat it with the fungicide “Quadris”, “Tilt” - this will prevent re-infection with the disease.
Biatorella cancer
The disease occurs in the same way as nectriosis - spores of the fungus Biatorella difformis settle in damaged juniper bark and wood. The penetration of infection is facilitated by the activity of insects that destroy the integrity of the bark. The disease spreads quickly, causing necrosis of the bark: its browning, drying out, cracking. Subsequently, the wood gradually dies and longitudinal oval wounds form in it.The ulcers are deep, stepped, with ragged edges, more concentrated in the middle part of the branches and trunk, often on the north side. The disease affects junipers growing in unfavorable conditions and greatly weakens them, leading to drying out of the crop and reduced resistance to snow blowing. For treatment you should:
- cut out the affected parts of the plant;
- treat the juniper with an antifungal drug, paying special attention to the cut areas.
Alternaria blight
If the branches and needles of the juniper become brown and covered with a black coating, this indicates infection with the fungus Alternariatenus Nees. Subsequently, the needles fall off and the branches die. To combat the disease, juniper needs to be treated with the preparations “HOM” or “Abiga-Pik”, Bordeaux mixture. Affected branches must be removed by smearing the cut areas with garden varnish or oil paint on drying oil.
Fusarium
This juniper disease is also called tracheomycosis wilt. It affects plants of any age. The causative agents are anamorphic fungi of the genus Fusarium that live in the soil. They penetrate first into the roots of the juniper, causing their partial rotting, then into the vascular system, preventing the movement of juices. By the time the disease appears in the aboveground part, the plant will already be affected by the disease to a significant extent. The presence of whitish or reddish fungal spores in the area of the root collar and a dark ring on the cut of the branch will help to identify a hidden disease of juniper.
At the first symptoms, the soil should be treated with solutions of biological preparations “Fitosporin-M”, “Agat-25K”, “Gamair”, “Fundazol”, “Alirin-B”. You can try to save the juniper from the disease by cutting out the affected branches and treating the cuts with copper sulfate.
Schutte
Schutte is a group of diseases that affect conifers. It manifests itself as redness, drying out and death of the needles. The cause is pathogenic fungi of various genera. On juniper there are 2 types of schutte.
Brown
The causative agent of the disease is the fungus Herhpotrichianigra. Infection occurs in the fall, development occurs in winter under snow cover at a temperature not lower than + 0.5 ˚С. The disease appears in the spring, in March-April. After the snow melts, yellowed needles are visible on the branches, covered with a snow-gray coating reminiscent of a cobweb. Over time, it darkens, becomes black-brown, dense, and “glues” the needles together. The needles turn brown, but do not fall off, held together by mycelium. In autumn, round spores appear on them.
Juniper Schutte
The disease is caused by the fungus Lophodermium macrosporum. Symptoms: in the spring, the needles of last year acquire a yellow-brown color and do not fall off for a long time. By the end of summer, it becomes overgrown with mushrooms up to 1.5 mm in diameter.
To treat both types of schutte, the same measures must be taken:
- cut out diseased parts of the plant;
- treat with fungicides “Strobi”, “Skor”, “Ridomilgold”, colloidal sulfur.
Juniper pests and their control
Juniper is attacked by pests to a lesser extent than other conifers; there are not many species of insects that have adapted to the specific feeding habits on it. However, their vital activity can lead to loss of decorativeness and death of the plant. Parasites that harm juniper are divided into sucking and pine-eating. It is important to identify the infestation at an early stage and treat the plant in a timely manner to prevent insects from multiplying and causing severe harm.
Juniper sawfly
The adult sawfly is green in color, with a brown-green head. The larvae, false caterpillars, are green, with stripes on the body. They eat needles and young shoots. Lives in the ground, in the tree trunk circle. The fight against insects consists of digging up the soil in the root zone, destroying larvae and nests manually, and using adhesive belts. For the best result, the plant must be treated with insecticides “Bi-58” and “Kinmiks”.
Juniper scale
Lives in needles and cones. The larvae are light yellow in color, up to 1.5 cm in size, and suck juices from the bark. This leads to its death, infection with fungal spores, decreased immunity and slower growth of juniper. A 0.2% solution of Karbofos is effective in combating them. If last year there were already problems with scale insects, in the spring the juniper must be treated for preventive purposes.
Spruce spider mite
Its presence is indicated by the cobwebs densely entangling the branches of the juniper, yellow spots on the needles, and their shedding. The insect reproduces very quickly: it reproduces up to 4 generations per season.During the growing season it can destroy the plant, especially young seedlings. To destroy spider mites, it is recommended to treat the crop with acaricides “Sumiton”, “Aktellik”, “Karate”.
Pine moth
The moth is a lepidopteran butterfly that destroys juniper needles in the summer-autumn period. The wings of males are dark brown, while those of females are red-brown with whitish or yellowish spots. The caterpillars are initially green with a yellow head, later becoming blue-green or yellow-green with 3 longitudinal white stripes. It reproduces intensively in hot, dry summers and warm autumns. In October, the larvae descend into the litter, where they pupate and overwinter. Infection is diagnosed by inspection: eaten away grooves and notches appear on the needles.
Larvicides that are effective in the fight against larvae are: “Methyl-nirofos”, “Baytex”, “Arsmal”, “Parisian green”. To treat plants against moths, you should use the products only in special clothing and using respiratory protection. Early autumn frosts can completely destroy their population on juniper.
Gall midges
Gall midges are small mosquitoes up to 2.2 mm in length. As a result of the bites of the larvae (yellow-orange in color), cone-shaped galls appear, consisting of 3-4 whorls of needles. Galls are used by insects for food and shelter from entomophagous predators. As the larvae grow, the tops of the needles bend outward. Treatment: treat with Fufanon, Actellik, Komandor, Iskra, Intavir.
Ants
Ants are equally beneficial and harmful. They loosen and structure the soil, eat the larvae of harmful insects, and enrich the soil with organic matter and humus. The significant harm that comes from them is the breeding of aphids on the above-ground parts of the juniper and in the roots.The plant receives damage, which slows down its development and growth. The activity of ants can lead to the death of juniper. Ants also cause harm by transferring diseases from plant to plant. To get rid of insects, you need to find an anthill and treat it with Actellik and Fufanon.
Aphid
A small wingless insect of brown color with two longitudinal stripes on the back. It feeds on juniper juices, weakening it. Young shoots and seedlings are especially affected. The fight against aphids begins with the destruction of ant nests. For best results, juniper should be treated with toxic compounds:
- solution of anabasine sulfate (20 g per bucket of water);
- "Rogor";
- Mospilan;
- "Decis";
- “Confidor;
- "Calypso".
Also against aphids, juniper can be treated with a soap solution (250 g per 5 liters of water). When treating the crown, you need to ensure that the composition does not get into the root zone.
Preventive actions
It is easier to prevent a disease than to treat it. Preventive measures taken in a timely and regular manner can ensure the health of the juniper and protect it from diseases and pests. The basis of juniper care is:
- Compliance with the rules of agricultural technology - site selection, soil composition, mulching, loosening, fertilizing.
- Timely application of fertilizers and immunomodulators. “Super-humisol”, “Epin-extra”, “Siliplant”, “Nikfan” have proven themselves well as root and foliar fertilizers.
- Regular sterilization of garden tools, soil, containers for seedlings.
- Liming of acidified soils. Excessive soil acidity contributes to the occurrence of fungal and viral diseases.
- Complete nutrition of juniper, forming immunity, sufficient supply of potassium, phosphorus, nitrogen.
- Using healthy planting material and carrying out measures to quarantine new plants.
- Destruction of harmful insects - carriers of diseases.
- Soaking the roots before planting in Fitosporin, Vitaros, Maxim.
Favorable conditions for the development of diseases are dense plantings, excessive shade, high humidity, and soil acidity. When choosing a place to plant juniper, you need to choose lighted and ventilated areas with light, well-drained soil. To prevent diseases, the plant should be treated twice a year with solutions containing high copper content, colloidal sulfur, and systemic fungicides. Removed branches, bark and needles that fall off during illness must be burned.
Conclusion
Juniper diseases arise as a result of the plant being in unfavorable conditions, which initially impair its development. In this case, the gardener needs to pay increased attention to the crop - provide adequate nutrition, loosen the soil, remove weeds, inspect for the appearance of parasites and pathogenic microflora, and attract beneficial insects to the site. Then the juniper will be a real decoration of the garden for many years.
