How to treat brown spots on iris leaves. Diseases and treatment of irises
Many growers are of the opinion that irises do not give their owner any trouble at all. But is it? In recent decades, iris breeding has made great strides. Iris varieties, amazing in their beauty and sophistication, were bred. Experience has shown that the more original and beautiful the variety, the more attention it requires in terms of the exact observance of the basic agricultural techniques. Take a closer look at the area where you have irises. If there is strong shade, stagnant water, if the winter was little snow and frosty - such plantings can be susceptible to diseases! Many amateur flower growers tend to buy an iris with a flower and transplant it to their site. From a purely human point of view, you can understand them - a person sees what kind he buys, but from the point of view of elementary agricultural technology of irises, this is unacceptable! The flowering period of iris is the time of maximum use. nutrients... During this period, even the foliage stops growing. If we disturb the peace of the iris during this period, then we will damage it. root system and thus reduce the intake of water and other nutrients. We disrupt the development of new daughter blades of irises, thus harming the breeding process of the bush. Various harmful microorganisms multiply very actively during this period and, penetrating through the plant tissue damaged during transplantation into the root system, cause plant decay.
I would like to note that the development of iris diseases is greatly influenced by geographical position site and, accordingly, the climatic conditions of growth. Already, the list of iris diseases is quite large and impressive. Is there a way out of this situation? Is it possible to protect our pets from bacteriosis of rhizomes, bear, rust, finally? You can and should!
If the florist observes the basic rules of agricultural technology, then he will be able to grow a healthy and viable planting material... First of all, I would like to draw the attention of our lovers of irises to the need to reproduce irises only from healthy bushes. If you notice signs of a viral disease on irises, immediately discard (destroy, in other words) such iris bushes. It is necessary to carefully monitor the plantings and promptly remove the decayed remains of the bushes. Delay in this case threatens mass infection of the entire iridarium. Very good results in the fight against such a disease of irises as Fusarium are given by the use of the drug Fundazol. They can water the plants (0.2% solution) under the root, and also pickle individual rhizomes in it before planting. If there were prolonged rains in the summer, use a solution of potassium permanganate after each such "wet" period. A solution of Bordeaux mixture will help you combat iris spotting.
The florist is not only bothered by iris diseases, but also by pests - gladiolus thrips, slugs, wireworms, hover flies, bear, iris scoop.
Winter moth and Iris scoop. These pests eat away the bases of irises flower stalks, which leads to their yellowing and rapid death. After the scoops have ruled the bush, the iris can be affected by bacterial rot. To prevent scoops, treat the iris bushes with karbofos (10% solution) several times.
Thrips. Although this insect is small in size, it does very significant harm. Thrips settles in dense, unopened iris leaves, which makes them turn brown and dry. This pest loves not only iris leaves. After a while, it moves to flowers. The buds of such plants bloom very sluggishly or do not bloom at all. Thrips thrips well in hot dry weather. Against him, you must use the same solution of karbofos. Alternatively, you can offer an infusion of shag (about 0.5 kg) in a bucket of water. For better adhesion of this solution to iris leaves, you can add laundry soap to it.
Medvedka is a great danger for planting irises. The insect itself feels good underground, on the ground and even in the air, causing significant harm to plants, especially in the south of our country.
Ways to deal with a bear
If you add a little washing powder to a bucket of water and pour this solution into the holes where the bear moves, you can force it to crawl out to the surface where it can be easily collected by hand.
Do not throw away eggshell in winter. Collect it in sufficient quantity, grind it into powder in spring, add for smell sunflower oil and place one teaspoon at a time in the wells. Medvedka most often dies after having tasted such a "treat".
Slugs. This clam has a great appetite. By the way, he loves it very much bearded irises... The signal that slugs have appeared is the presence of silvery mucus on the leaves and oblong holes on them. Reproduces well in wet weather. Fallen, affected by diseases, iris leaves eats with great pleasure. Then, crawling onto healthy plants, infects them. To minimize slug damage, spread damp rags in your garden beds. The slug is nocturnal, so during the day it will probably use a damp cloth as a hiding place. You will be able to assemble it manually. Good results are obtained by using granular metaldehyde.
Wireworm. Signs of a pest in the garden are long passages in the rhizome of the iris. The beetle itself is black, the larva is yellow or brown. To combat the wireworm, tinctures of insecticidal plants (bitter pepper, pyrethrum) are used. Tinctures must be kept for 24 hours before use. For greater effect, add laundry soap to the solution.
Still, irises are more disease resistant than other plants. However, a few words should be said about them. One of the most dangerous diseases is bacteriosis or soft rot of rhizomes. Signs of the presence of the disease: browning of the tips of the leaves and, as a result, their drying, stunting in comparison with other iris bushes. The diseased leaves are easily pulled out of the fan and give off an unpleasant odor. The spread of the disease is facilitated by poor wintering of iris plantings, high humidity and thickening of plantings. Do not apply manure under irises - this also provokes the development of bacteriosis! If you notice such plants, immediately discard them. Before planting, pickle the rhizomes in a weak solution of potassium permanganate. If you transplant irises, then after dividing the bush, sprinkle open cracks with ash and allow the iris blade to lie in the shade for 2-3 days so that the wound from the fracture dries up and heals. Do not plant irises in the same place all the time, observe the crop rotation.
Fusarium and gray rot. Signs of diseases: decay of roots and drying of rhizomes, transient yellowing of leaves and peduncles. Poor wintering, high humidity and excess nitrogen in the soil lead to these symptoms. To avoid this, it is necessary to plant irises in well-ventilated and sunlit areas, timely remove heavily affected bushes, pickle the rhizomes before planting and treat the plants with fungicides.
Heterosporia (leaf spot). I think that every iris grower observed signs of this disease in his area: brown-yellow spots are formed on the leaves, which leads to the drying of the leaves. Fortunately, the disease is not as dangerous as the previous ones, but it greatly spoils the appearance of irises. What can be recommended as prevention? Remove iris leaves in a timely manner if the first signs of the disease appear on them. You can spray the affected plants with copper preparations.
On the site, you can encounter iris diseases such as rust, ascochitis, septoria. As a prophylaxis, it is possible to recommend crop rotation (return of iris plantings to their original place not earlier than after 5 years), as well as spraying with copper-containing, zinc-containing preparations and a suspension of colloidal sulfur.
Mosaic. This is a viral disease of irises. Light shading becomes visible on the leaves, the petals become variegated. It is impossible to cure this disease. However, if you adhere to the basic rules of agricultural technology, you can try to hide the consequences of the disease. However, the plant will remain a disease carrier for healthy shrubs. It is necessary to discard the affected specimens in a timely manner and fight against disease-carrying insects.
An important factor in the fight against iris diseases is the disinfection of the cutting tool. The use of contaminated cutting tools is considered the main mechanism for the spread of iris diseases. This occurs during the period of division and transplantation of overgrown bushes, when the old rhizomes, roots and the upper part of the leaf fan are cut off on many plants of the existing collection with the same knife or pruner.
To completely exclude the possibility of such an infection, it is necessary to accustom yourself to divide each separate bush with a separate disinfected tool. Let me remind you once again that on the surface of cutting blades in dried cell sap, viruses retain their virulence for about 3-4 days, and the temperature of their death is approximately + 72 ° C.
Antiviral disinfection methods for cutting tools:
- Calcination of the cutting part (blade) on an open fire for 1–2 minutes;
- Sterilization in boiling water for at least 30 minutes;
- Sterilization in pure (96%) industrial or ethyl alcohol for at least 15 minutes;
- Excerpt in a 5% solution of potassium permanganate (pharmacy potassium permanganate) for at least 15 minutes (5 grams of KMnO4 per 100 ml of pure water);
- Excerpt in pure 40% formalin for at least 15 minutes.
When dividing and transplanting, use as little as possible cutting tools... It is better to simply break off the fan with a part of the rhizome from the old part of the bush. Leaves do not need to be shortened, and this will not in any way affect the survival rate of the cut. In this case, do not touch with your hands oozing wound surfaces (cuts, cuts or fractures). Cutting the peduncles can be done with the same tool, but - with the subsequent immediate manual breaking of the remainder of the flower shoot. Rhizomes that decay during the growing season are cleaned to a healthy part and immediately sprinkle the entire wound with dry potassium permanganate and rub it over the entire wound surface.
With my article I am not trying to scare iris lovers and plant a grain of doubt about the correct choice of irises as an attractive crop for growing. I can only say one thing: there are no problem-free cultures at all. I try to act according to the principle: forewarned is forearmed. Our family has been dealing with irises for at least ten years and is quite successful. Iris is one of the most beautiful flowers that deserves your attention and admiration. I will be glad if the material presented in this article will help you to consolidate in this very thought.
Irina Orekhova was with you
Tel .: 0662862622, 0952090093
Email: [email protected]
Measures for the control and prevention of bacteriosis. Plants are regularly examined, especially at the end of winter, after the snow melts, as well as during the period of active summer growth of young daughter divisions. It is necessary to ensure the outflow of melt water from the site. It is good if the area with the planting of irises has a natural slope, if it is not there, then the way out of the situation will be the placement of raised ridges. In the summer - the destruction of insects and soil pests that are carriers of diseases. In autumn - the use of sulfur in combination with fertilizers. In winter - protection against frost damage to iris rhizomes.
Treatment. The soil is removed around the base of the diseased bush. The affected rhizome is carefully examined. The areas affected by bacteriosis are cut out and scraped up to healthy tissue.
If the lesions are voluminous, then the bush is completely dug out. The trimmed parts of the plant are etched in a pink solution of potassium permanganate and treated with a fungicide or washed in a 10% solution of bleach.
Over the past years, for disinfection of wound surfaces affected by bacteriosis, I have been using 10% hydrogen peroxide, which has proven itself very well. Peroxide is a more effective antiseptic and acts not only superficially, like bleach, but penetrates deep into plant tissues.
If the lesions are small and local, then the holes in the iris rhizome (the rhizome is not completely dug out) cleaned out, carefully scraped out of putrefactive tissues, are treated with any antiseptic (chlorine-containing powder products, hydrogen peroxide, brilliant green, etc.) and covered with ash.
The treated wound surface of the rhizome remains open to the sun's rays until complete recovery. Every few days, the wound is carefully probed at the time of new decay. If necessary, the processing is repeated.
One of the most effective effective means prevention and treatment of irises affected by bacteriosis are antibiotic treatment of plantings. This advice was once received by me from the famous flower grower and collector Vasiliev OL (Moscow, Russia), for which I always remain very grateful to him. Antibiotic spraying and compliance preparatory activities to wintering have significantly reduced our losses of planting material of irises and sometimes practically reduce them to zero.
For preventive treatments of plantings in early spring (when the temperature rises above 10-12C), it is necessary to dissolve 2-3 g of antibiotic - streptomycin, neomycin, tetracycline or ampicillin in 5 liters slightly warm water(no higher than 55C!). Clean the plantings after wintering from plant debris and spray the irises, carefully shedding the backs of the rhizomes. During the extension of the peduncles, it is good to shed their base and sinuses between the leaves. If necessary, the processing can be repeated.
When the ambient temperature rises from 20C to 25C, the activity of the ervinia bacterium increases, therefore, with the threat of a bacterial epidemic, the concentration of the solution can be doubled - 1 g of antibiotic per 1 liter of water. Usually 2-3 sprays of such a concentration with an interval of 4-5 days is enough to stop even a very strong outbreak of bacteriosis.
The only rule is that you cannot abuse antibiotics, as over time the bacteria become resistant to a number of antibiotics used!
Additional preventive measures to combat Erwinia.
In spring - spraying on green foliage with a composition of urea and 12% sulfur.
Autumn - dusting plantings with colloidal sulfur - preventive long-term help.
A sharp change in day and night temperatures during the growing season, precipitation, high air humidity, May fogs and dews contribute to a strong damage to irises fungal diseases- botrytis, rhizoctonia, fusarium, etc.
Rhizoctonia
The causative agent is an imperfect mushroom Rhizoctonia solani... The disease is especially harmful in cold, rainy springs, when the fungus, infecting sprouts in the soil, causes their decay and premature death, which leads to plant losses and sparse plantings.
In young plants, rhizoctonia causes rotting of stems and roots. In adult plants, the leaves become darker in color and dry out. On the lower part of the stem and in the axils of the leaves, brown depressed spots appear, which are covered with a felt bloom, first white, later brown. Spores are oval, colorless, mycelium is brown, thick, multicellular. The disease is observed in early spring, in years with frequent winter thaws. It is spread by foci by contact-mechanical method.
Prevention and control measures for rhizoctonia
Preplant etching with MAXIM®, KS. Use of healthy tuber-rhizomes. Compliance with the rules of crop rotation. Cultivation of varieties with increased resistance to rhizoctonia. Timely spring planting of tuber-rhizomes in sufficiently (> 8 ° C) warmed soil.
Planting depth, taking into account the mechanical composition and moisture content of the soil (shallower on heavy soils, deeper on sandy loam). Loosening of row spacings during crust formation on heavy, floating soils. Autumn cleaning of the garden from weeds and dead plant residues.
In case of illness, water the soil in the lesions with potassium permanganate (3 g per 10 l of water).
"Penncoceb"- this broad-spectrum contact fungicide is able not only to protect plants from different forms rhizoctonia disease, but also contribute to the significant strengthening and growth of the leaf apparatus. As a result of treatment, plants can remain protected from rhizoctonia for up to two weeks. Wherein active substances the drug begins to act on the very first day after getting on the leaves.
As part of the fight against rhizoctoniosis, Penncoceb can be combined with most fungicides and insecticides (except for highly acidic and strongly alkaline ones) without harm to human health and the cultivated crops. However, on a case-by-case basis, it is strongly recommended that a compatibility check is carried out. Treatment for rhizoctonia should be carried out by spraying with a 0.2% solution 3-4 times during the growing season with an interval of 7-10 days.
Fusarium or Fusarium rot
Fungal disease ubiquitous. It affects tuber-rhizomes and stems at a height of 10 - 20 cm from the soil, often leading to the death of the plant. The harmfulness of fusarium increases with an excess of nitrogen in the soil, mechanical damage to the tuber-rhizomes of irises and depends on weather conditions. Obtaining infected planting material leads to the progression of the disease in favorable conditions for its development.
The spread of the causative agent of the infection occurs during the division of rhizomes. The infection persists in the soil and its development intensifies with increasing moisture. Infection occurs due to the infectious principle of the fungus, which remains in the infected soil particles. The larger the tuber-rhizome, the higher the likelihood of infection.
The development of the disease occurs at a wide temperature range from 2C to 32C, the maximum - at 12-17C.
The disease manifests itself on iris tubers. A focus of decay can be found in any part of the tuber. The first sign of the disease is the appearance on the surface of the tuber of a grayish-brownish dull spot, slightly depressed inward and characterized by slight wrinkling of the integumentary tissues. The flesh of the tuber under the stain becomes loose, dry and becomes brownish in color. With increased air humidity in the early stages of the development of the disease, the affected tissue may have a watery consistency, remaining loose. Later, the diseased tissue becomes almost black, and the tuber becomes light.
Prevention of fusarium.
Use of fertilizers with the correct combination of plant nutrients. Prevention of trauma to the root system of irises. Chemical treatment with contact fungicides. You can also apply the treatment of planting material with a 5% solution of bicarbonate of soda or 0.02 - 0.1 - solution copper sulfate... Systematic disinfection of agricultural equipment.
Botrytis
Disease caused by two types of fungus Botrytis convoluta and Sclerotium rolfsii Penetrates into the rhizome through damaged or weakened plant tissues. Infected rhizomes become dark brown and soft. Large dull black sclerotia are formed on them. The disease occurs under inappropriate storage conditions for planting material with high humidity and insufficient ventilation. Subsequently, with the onset of rains and cold weather, the disease progresses, develops and has a detrimental effect on irises. Heavily infected specimens lag behind in development
Prevention of Botrytis
Correct storage of planting material. Disinfection of rhizomes before planting.
Application of systemic fungicides of the triazole class - "Davidand" for dressing planting material.
Heterosporium or leaf spot
The disease is caused by mushrooms Heterosporium iridis and Mycosphaerella macrospora... It affects the leaves and stems of irises. The lesion begins noticeably with the outer aging leaves of the iris bush. Whitish-gray spots with a yellow, slightly watery border are formed on them. The spots grow and merge together. Infected leaves gradually turn brown and dry out. Soon, the disease affects the entire bush.
Prevention of heterosporiasis.
Excessive supply of potassium, phosphorus and trace elements. Preventive treatment with fungicides, starting from the appearance of the first signs of the disease with an interval of 7 - 10 days. Weed control. Removal of diseased leaves followed by burning. To increase resistance to the disease, spring spraying of foliage with a solution of calcium chloride or calcium nitrate is recommended. Calcium helps to increase the immunity of plants to diseases.
Rust
The disease is caused by a fungus Puccinia iridis and came to us from South America. The optimum temperature for the development of the fungus is 12C. Leaves are affected, yellowish-brown or dark-brown pustules form on their surface. The tissue around the pustules is dying off. Later, the leaves dry out. The disease leads to deformation of the stems and twisting and death of leaves. The fungus remains in plant debris and soil.
General preventive measures against bacterial and fungal diseases
1. Do not fertilize the soil with poorly prepared and not rotted composts from plant residues. Do not use fresh manure to fertilize irises!
2. Whenever possible, follow the rules of crop rotation and use disease-resistant varieties.
3. Observe good air circulation in the landings.
4. Periodic cleaning of plantings with removal and burning of affected plants is necessary.
5. Planting and transplanting plants into warm, deeply dug soil.
6. Autumn mulching of iris plantings.
7. Compliance with the planting depth, taking into account the mechanical composition of the soil and the climatic conditions of the growing area.
8. If necessary, adjust the acidity of the soil.
9. Sufficient comfortable surface watering.
10. Avoid stagnant melt and irrigation water.
11. Avoid any extreme stressful situations for the plant (drought, transplanting during flowering, etc.)
12. If infected leaves are found, seasonal sanitary pruning of foliage (1/3, 1/2) and cleaning of bushes is necessary, especially in monoculture gardens.
13. Fight against insect pests - carriers of various diseases.
14. Sanitary treatment of agricultural tools and devices.
15. Application of corrective doses of fertilizers and micronutrients.
16. Application of a wide range of chemical and biological plant protection products throughout the growing season.
Preventive spraying and dusting.
Including the use of copper-containing fungicides: "Bordeaux liquid", "Copper sulfate", "Copper oxychloride", "Kuproksat", "Kuprosil"... The mechanism of action of copper-based drugs is only prophylactic and protective. Therefore, fungicides of the copper group should be used in accordance with the forecast of the spread and development of phytopathogens. Plants must be sprayed with working mixtures of preparations from the beginning of the flight of the spores to the possible infection of the tissues of the host plant. When a pathogen enters plant cells, drugs of this group are not able to destroy it. The duration of the protective action of copper-containing fungicides is 10-20 days. Therefore, the subsequent use of drugs is due to weather conditions, the intensity of the development of the disease and the duration of the protective effect of the fungicide.
At the first symptoms of fungal diseases (at least on one of the plants), all plantings must be treated with fungicidal preparations of enhanced action, such as Fundazol, Quadris, Ridomil Gold, Bravo, Tatu, Fitosporin-M, Champion... If the disease has already developed enough, then it is important to carry out several treatments of irises at intervals of 6-8 days.
There are many more fungal diseases that also spread to irises.
Subject to the methods of correct agricultural technology and keeping the plantings in a clean state, as well as the observance of the above listed methods of control and prevention, will avoid these diseases.
viral lesions, viroses
Among the infectious diseases of irises are viral lesions in the form of various mosaics, deformations, chlorosis, growth inhibition, and the death of certain parts of plants or tissue sites. These lesions are caused by viruses, viroids and mycoplasmas, which, differing in biology and the nature of their effect on irises, have much in common (transmission of infection to subsequent vegetative reproductions, transfer characteristics, etc.), in connection with which a unified system of measures to combat these infections has been developed. One of the main carriers of viral infections are ubiquitous aphids, leafhoppers, bugs and, to a limited extent, nematodes, thrips, ticks, etc.
One of the most characteristic features virozov is the appearance on flowers of uncharacteristic folds, wrinkles, blistering over the entire surface of the petals. The color of iris petals changes, it becomes variegated. The edges of the petals seem to melt. Light-colored varieties take on a dirty, oily paper-like color with noticeable chaotic strokes. A general suppression of the iris bush is visually observed. Peduncles become brittle.
Methods for the control and prevention of viroses
Fight against the main virus carriers, pests of irises. Obligatory systematic disinfection of agricultural tools. The introduction of quarantine measures. Complete destruction of infected planting material. Preventive use of fungicides on plantings against phytopathogenic fungal diseases.
Functional diseases are noted in case of disturbances in the balance of plant nutrition (signs of a lack or excess of nitrogen, potassium, phosphorus and trace elements), high temperatures, lack of oxygen in the soil, low and negative temperatures, disruption in normal tissue metabolism, air pollution.
A set of measures aimed at protecting iris plantings from diseases, as well as the leading role assigned to prevention, allow us to suppress pathogens and pests in the soil. Measures aimed at suppressing weeds with the use of herbicides are of great importance.
Iris pests
I will briefly describe the characteristics of the main pests and methods of chemical protection of iris plantings from pests.
When determining the need to use pesticides, environmental thresholds of harmfulness should be taken into account. Prevention plays a leading role in pest control. Prophylactic methods of various content and orientation allow us to suppress pathogens and pests in the soil. There are no specialized pests for irises.
In some years, wireworms, bears and slugs multiply and harm in mass. Sucking insects - thrips, aphids, spider mites and nematodes living freely in the soil, which are active carriers of phytopathogenic viruses and mycoplasmas. Disease and pest control measures should be aimed primarily at suppressing or destroying their complex in the most vulnerable phases of development.
TRIPS
Small insects 0.5-1 mm. The oral apparatus is piercing and sucking. The color is inconspicuous: black, gray and brown colors prevail. The larvae of thrips are colored in light white-yellow, grayish or greenish tones. This makes them hardly distinguishable on the surface of the leaf blade.
They feed on plant cell sap. Causes deformation and discoloration of iris leaves. The rhizome of the plant is also damaged, on which brown spots are formed as a result.
The most common are decorative, variegated, western floral (Californian) and some other types of thrips. All of them prefer a secretive way of life - in the stamens of a flower, in buds, or in the axils of leaves. For wintering, they descend into the soil on the roots and in the scales of the bulbs. Thrips reproduce very quickly at their optimum temperatures (+ 20 ... + 25 ° C). During the growing season, irises give several generations.
thrips adult-flight phase
Prevention and control measures
Digging up the soil. Destruction of weeds on which thrips multiply. Watering in hot dry weather. Autumn sanitary cleaning of plantings with cutting off part of the foliage.
With a massive appearance, spraying with organophosphorus preparations. Considering the biological development cycles of thrips - eggs, nymph larva, adult flying specimen, three times treatment with an interval of 7-10 days with such preparations as - "Mospilan", "Regent", "Vertimek", "Aktelik", "Marshal", " Aktofit ". Use the recommended spray rates for spraying.
Against thrips on irises, the drug BI-58 has proven itself well. To increase the effectiveness of the action, it is advisable to add a surface-active substance (surfactant) of the "Trend 90" type to the working solution. Repeated spraying with a 10% concentrate of karbofos emulsion (75-90 g per 10 liters of water) helps with thrips. Spraying with approved insecticides at intervals of 7 days.
APHID
Insects are 2-3 mm long. They accumulate in masses on young leaves and flowers. It multiplies very quickly. It sucks juices out of plants, often strongly deforming the leaves, oppressing and weakening the plants. Sucking a large amount of sap from plants, aphids excrete excrement in the form of a sticky liquid that contaminates the leaves. Saprophytic sooty fungi settle on these secretions, which, while multiplying, cover the surface of plants with a solid black bloom, thereby impairing the processes of respiration and nutrition of plants.
Prevention and control measures... Spraying with 0.3% karbofos emulsion, 15% phosphamide emulsion. Effectively spraying with a 0.5% solution of soda ash with the addition of 0.5% soap. Weed control.
Scoops
Butterfly from grayish-yellow to brownish color. The caterpillars are elongated-cylindrical, clearly segmented. Coloring from yellow-red to reddish. The result of sabotage is wilting and yellowing of leaves, breaking off of stems. At the level of the soil on the stems, an entrance hole is often visible on the outside. Inside the underground and aboveground parts of the stems, passages filled with excrement were eaten away. The scoops are widespread and only cause limited damage in low and damp areas.
Complex of agrotechnical and biological measures is aimed at the destruction of weeds, especially cereals, on which populations of moths in unfavorable conditions winter period preserved in the egg stage. Deep digging and systematic loosening of soil between rows to destroy pupae. Treatment of pest reservations during the egg-laying period with biological agents - Trichogramma. Spraying plants with a solution of 10% conc. karbofos emulsion (75-90g per 10 l) at the beginning of the growing season twice with a break of 7 days. Application of organophosphate insecticides. Catching butterflies with light traps. For the destruction of caterpillars, spraying with a decoction of Chemeritsa Lobel (Veratrum lobelianum) is recommended.
BEARS
Insect with two pairs of wings, powerful jaws and front digging legs. The body is 35-50 mm long, 12-15 mm thick, brownish-yellow from above with a silky shade from below.
Pest - wilting and death of plants as a result of gnawing roots and stems. Gnawing the pulp of tubers.
Control and prevention measures: deep digging of soil, introduction of anhydrous ammonia, loosening of row spacings. Destruction using baits mixture - 1 kg of boiled grain, 30 g of sunflower oil, 50 g of karbofos. The baits are buried in the soil to a depth of 3–5 cm, or they are buried in the holes of the bear. Digging out bears, larvae and their nests with eggs, destroying them. Fishing on heat traps with fresh horse manure. Installation of traps - cans at ground level in places where the bear congregates.
WIRE
The larvae of the click beetle are elongated-cylindrical with a hard chitinous cover, clearly segmented, the head is flat, 3 pairs of pectoral legs of the same length, the color of the larvae is from yellow to brown. Body length at the end of development is from 10 to 28 mm. During the growing season, wireworms live in the zone of roots and tubers.
A set of preventive and exterminatory measures: liming acidic soils and the introduction of anhydrous ammonia, active tillage, destruction of weeds, especially wheatgrass. The introduction of granules of soil insecticides. Bait sowing of grain crops with seeds treated with insecticides. The use of drugs - "Bazudin", "Diazinon", "Calypso".
KIVSYAK 
Small animals with a worm-like body, consisting of many segments, bearing two pairs short legs... Length from a few millimeters to 5 cm or more. They move slowly, disturbed - curl up in the form of a clock spring. They reproduce by eggs, which they lay in heaps in the ground, under stones and other objects on the soil surface. They live under fallen leaves in the upper layers of the soil and under various plant debris. They feed on dead parts of plants, dead insects and worms, as well as ripe fruits and berries lying on the ground. One of the active converters of compost into garden humus. Kivsiak can be both a primary and a secondary pest of horticultural crops, including damage to the rhizome of the iris.
CRUSHY, BEETLES
The main harm to the planting of irises is carried by the larvae gnawing the rhizome. Adult beetles and bronzes are significantly harmful decorative appearance flowers.
larva of bronzovka
The larvae are C-shaped, segmented, with three pairs of thoracic legs of different lengths, the head and legs are light brown, the body is white to yellow-white. Body length up to 60 - 65 mm. Eats out cavities in tubers without peel residues at the edges. Damage to plant roots.
european marble beetle Polyphylla fullo L. adult
European (June) marble beetle- polyphage. Beetles feed on pine needles, beech leaves, white acacia, poplar and other trees. The larvae gnaw at the roots of young trees and shrubs and other plants. Reproduction is bisexual, development is complete. Hibernates in the larval stage. The full development of an insect lasts three to four years. Beetles eat very little. The greatest harm is caused by the larvae of the beetle, especially last year... Most of all, the species gravitates towards sandy soils.
furry deer mating season 
shaggy bronze, shaggy deer Epicometis hirta Poda
Shaggy deer (common)- damages buds, flowers, ovaries and young leaves of a wide variety of deciduous trees and shrubs. Many food plants for the pest are herbaceous plants and root vegetables. Reproduction is bisexual. Development is complete. Young beetles hibernate in a cocoon. One generation develops in a year.
golden bronze Cetonia aurata
Bronzovka is often mistaken for an ordinary May beetle, since they belong to the same family. These insects can be distinguished by their bright metallic color and flight. It feeds on flowers of wild and cultivated plants. Beetles are very voracious, destroy flowers of fruit and berry and ornamental crops, suck juices from plants, leaving behind cut and gnawed flowers.
Beetles completely gnaw out the stamens and pistils - the reproductive organs of plants located inside the flower, therefore their pollination and fertilization becomes impossible, which means that the maturation of fruits and seeds is also impossible.
At the same time, ornamental plants cease to perform their function, acquiring a nondescript appearance and losing their aroma.
damage to flowers by beetles
Control and prevention measures: Until now, there are no exact instructions on how to get rid of the bronze, since until recently, it did not pose a big threat. Today it is the main pest of the decorativeness of a blooming garden.
Catching beetles using light traps, collecting and destroying larvae when digging the soil. Collecting and shaking off beetles by hand is not particularly effective, since others will come to replace the destroyed bronze ones.
The larvae of these beetles live in rotten wood or in heaps of humus, therefore, if you clean your area from fallen leaves and fruits, old stumps and remnants of decaying wood, the likelihood of the appearance of adult beetles will significantly decrease.
Chemical method - Radical is used in industrial fields. Poisoning of larvae in the soil before planting plants with the gamma isomer HCH or other pesticides intended for this purpose. Timely treatment of contaminated soils with pyrethroids, organophosphorus compounds, neonicotinoids. Introduction of anhydrous ammonia.
SLIMS
Slugs are elongated-oval in shape, on the upper side of the body they have an oval shield, on the head there are two pairs of tentacles, smooth, covered with mucus, yellow-brown in color. Body length up to 60 - 70 mm.
During the growing season, slugs live in a well-humidified top layer soil and lower tier of leaves. Harm at night. They eat up leaves and eat up cavities in tubers. In the habitats of pests, dried shiny mucus is clearly visible. The optimum temperature for the development of slugs is 18–20C. Especially great harm is done in years with a large amount of precipitation in the summer and autumn periods.
Complex of extermination and preventive measures: drainage of waterlogged areas, deep digging of soil, destruction of weeds, removal of plant residues, layout of poisoned baits and sieving of metaldehyde granules. Dusting the soil with ash, a mixture of fluff lime and tobacco dust. Spraying plants with a decoction of bitter capsicum. Unfolding baits with subsequent manual collection of slugs. Dusting the soil with ground superphosphate, ferrous sulfate or ammonium sulfate.
NEMATODES
A number of diseases on irises cause nematodes of which the most widespread and harmful are gallic, potato golden, stem.
Signs of damage: plants lagging behind in development, affected rhizomes, which subsequently rot.
Control methods - application for disinfection of nematicides, weed control.
Nematodes are whitish, almost transparent worms. The length of the female is 0.8-1 mm, the male is 0.5-0.7 mm. Hibernates at the base of plants, in the buds at all stages of development. Withstands harsh winters. Nematodes live on plants between the glandular hairs. They feed on the contents of plant cells, piercing the epidermis with a stylet. As a result, the damaged tissue turns brown and dies. The nematode spreads with infected planting material, rain and irrigation water, as well as plant debris, weeds and agricultural implements. It is an active carrier of phytopathogenic viruses and mycoplasmas.
Control and prevention measures: strict quarantine. Weed control. Systematic disinfection with 10% formalin solution or 3% ammonia solution of agricultural equipment. Destruction of nematode foci and thermal disinfection of soil with hot steam. Spraying with nematicides and a decoction of calendula flowers. Disinfection of iris tubers by heating for 10 minutes in water with a temperature of 35C and the next 10 minutes in water with a temperature of 46C, followed by cooling in cold water and immediate landing. A method that excludes the use of chemicals.
The main conditions that determine the effectiveness of fighter techniques are - right choice pesticides and their combinations, the timing of treatments and their frequency, methods of treatment.
The type of pesticides, the timing and methods of spraying are closely related to the phases of plant development, the peculiarities of the biology of pathogens and pests, and their relationship with plants. Therefore, violation of the rules for these parameters can significantly reduce the role of chemical method in the suppression of harmful organisms and do not give the expected effect.
IRIS FLY, IRIS FLOWER - FLOWER Acklandia servadeii.
Gradually descending from the eastern and northeastern regions, this malicious pest conquers everything more territories Ukraine. Over the past ten years, the fly has begun to master the right-bank part of Ukraine.
The iris flower girl looks very similar to an ordinary fly, hibernates in the ground, and in the spring, when the plants are just beginning to grow, she crawls out of the ground and lays eggs in the buds of irises. The scientific name of the species was first published in 1933.
Iris fly Acklandia servadeii Séguy is an dangerous pest hybrid irises. The flight of adults lasts from the end of the third decade of April to the end of the second decade of May. The larvae develop for about two weeks. They pupate in the soil between rhizomes in wet weather. Pupation can last until the end of July and depends on weather conditions, especially soil moisture. As a result of feeding the larvae, the buds do not open, they rot, 2–5 larvae develop in one bud, and the damage on susceptible varieties reaches 100%.
iris fly
photo source www.irisocvet.ru
The article gives a complete picture of this pest, which is malicious for iris. http://www.nbuv.gov.ua/old_jrn/Chem_Biol/Vkhet/2006_14/182_popo.pdf
- "... In 2002–2009, an outbreak of harmfulness of the iris flower fly (iris fly) is observed in Donetsk region. Its taxonomy, as well as distribution and biology in Ukraine have recently been described. Hybrid irises (bearded) are damaged, and in some places the lesion reaches 100%. Flies lay eggs in iris buds, larvae feed inside the bud, which begins to rot and does not bloom. early varieties, which bloom before the beginning of May, are not damaged, although adult flies, feeding on their petals, also damage decorativeness. The species has one generation per year. Mandatory single treatment with drugs from the group of neonicotinoids is recommended (it is recommended to use primarily neonicotinoids based on different active ingredients: imidacloprid (Confidor, Confidor-Maxi, etc.), acetamiprid (Mospilan), thiacloprid (Calypso, Proteus, Bizkaia) and thiamethoxam (Akta , Engio, Cruiser, Denomination).) At the stage of the beginning of budding, when the flower arrow just emerges from the rhizome (usually the first days of May) ... "G.V. Popov" 2009)
Another source recommends at least two insecticide treatments
the first - on the leaves before budding, and the second - when buds appear.
Affected buds must be picked off and destroyed! Fly larvae with fallen infected buds overwinter in the soil.
Beneficial insects and guests of the iris garden
bumblebee Bombus
white butterfly Pieridae
honey bee Apis mellifera
wasp Vespula vulgaris
honey bee dark Apis mellifera mellifera L. (Black bee)
grasshopper green Tettigonia viridissima
bee Andrena sp. (Hymenoptera: Andrenidae)
hoverfly larva
hawk moth caterpillars dead head Acherontia atropos
Long-legged mosquito, or karamora Tipulidae
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Olga Orlovskaya 04/17/2015 | 4908
Improper agricultural technology leads to the appearance of pests on irises or the occurrence of fungal diseases. How to understand what plants are suffering from, and how to help them?
To save the irises in time, you need to constantly monitor them. Only attentive flower growers have no problems with plants in a flower bed.
Iris pests
1. Iris fly. If your irises refuse to bloom, an iris fly may be the cause. This is a very noticeable insect, the larvae of which damage the buds, so the plant does not bloom.
What to do? At the very beginning of the growing season, treat the planting with insecticides: Aktara, Aktellik. Spray the unpainted buds a second time.
2. Golden bronze. The green mother-of-pearl beetle is known to every grower. Bronzovka breaks the sepal of a blossoming flower from the inside, due to which the plant loses its decorative effect.
What to do? If there are few insects, then pick them up with your hands and place them in a soapy solution. If the population is large, treat irises with Bifenthrin or Imidacloprid.
3. Furry deer. This beetle is not as recognizable as the Bronze beetle, but no less harmful. The insect is black, hairy, about 10 cm long, with wings decorated with white markings. Eats out the buds and flowers of irises.
What to do? Collect the pests by hand. Place containers next to the irises of blue color(it is blue that for some reason especially attracts a deer), pour water into them with the addition of Aktara, Angio, Calypso.
4. May beetle larvae. The May beetle is a real disaster for the grower. The larva stays in the ground for up to 5 years, eating the roots of plants.
What to do? The most effective way is to manually pick the pests. Dig up the plant and destroy the larvae. Adults can be collected as follows: place containers of water with kerosene added under garden lamps at night.
The damage is caused by the larvae of the pest, which eat the rhizomes of the irises. As a result, the underground part of the plant begins to rot, the leaves wither, turn yellow, and the iris dies.
What to do? Before planting, hold the rhizomes of the irises in the Karbofos solution: for 10 liters, you will need 30 g of the drug.
Iris diseases
1. Bacteriosis. If the tips of the irises dry up, check to see if the rhizome of the irises has begun to rot in the areas where the leaves are growing. As the disease progresses, both the aboveground and underground parts of the plant completely die: the leaf plates rot away, and the underground part turns into a soft gruel.
What to do? During planting / transplanting of irises, carefully inspect the planting material. If there is a suspicion of bacteriosis, remove the damaged parts, treat the sections with potassium permanganate, sprinkle with ash. Dry the rhizomes in the sun for several days. Destroy the affected specimens, spill the ground with a fungicide solution.
2. Rust. This fungal disease can be diagnosed by the brown streaks on the leaves. When you touch them, red dust remains on your hands. Over time, the plant dries out completely. The disease most often manifests itself with the onset of autumn.
What to do? To prevent the disease in mid-July, spray irises with Bordeaux liquid. But treat the affected specimens with one of the following drugs: 1% Cuproxat, copper oxychloride, colloidal sulfur.
3. Leaf spot. The first signs of this disease appear on the outer leaves of irises: brownish-gray spots with a pronounced border. Over time, the fungus covers the entire plate, which leads to the drying of the leaves. Rhizomes are not affected.
What to do? Remove the affected parts of the irises, spray the bushes with Bordeaux liquid or fungicides (Fitosporin, Maxim).
4. Botrytis. Fungal disease, which is also called gray rot. The pathogen affects both the stems and leaves of irises, and rhizomes. At first, the peduncles and tips of the leaf plates lose color, then turn brown, rot and become covered with a gray bloom. The rhizome is overgrown with black mycelium of fungi, which inhibits the growth of leaves.
What to do? Delete heavily infected copies. Dig up the rest, wash well under running water and dry in the sun for a few days. Treat with Bordeaux liquid.
5. Scorch... This is a new, completely unexplored disease. The causative agent is presumably mycoplasma. Approximately in the middle of the season, the tips of the leaves dry out and curl up in the affected plant, the root processes die off, and the rhizome becomes hard and dries up.
What to do? Destroy the infected specimens, and treat the land in which they grew with Formalin. While no methods of treatment are known, the following preventive measures are recommended: plant valuable varieties of irises in several sections, at some distance from each other. This disease does not spread from one group of plants to another.
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There is an opinion that irises are unpretentious and, in general, there are no worries with them. But the more refined the varieties, the more they are picky about environment and any violations of agricultural technology. An example is the strong shade of your site, winters with little snow with very low temperatures, stagnant water and, as a consequence, the clogging of rhizomes. And, of course, it is absolutely impossible to violate the landing dates. Plants are divided and replanted after flowering, this should be the rule for everyone. It is completely unacceptable to replant flowering plants. Any flowering requires the maximum consumption of nutrients from plants, while the growth of leaves even stops, and if the roots are still damaged by untimely transplantation, then the absorption of water with dissolved substances will decrease, new daughter plants that develop on old rhizomes suffer. In addition, this immediately causes the active growth of all pathogenic microorganisms, which are always present in huge numbers both in the soil and on plants. The likelihood of infection during transplantation increases, because through the damaged tissue, the fungi penetrate the roots with their mycelium and cause decay.
Each region has its own specifics. The harmfulness of diseases and pests varies significantly with climatic and weather conditions. So, enemy number one for irises in the north-west of the European part of Russia is bacteriosis (soft rot) of rhizomes, in the southern regions the bear is a big trouble, in the south-western regions it is rust.
How can we protect our plants from so many misfortunes? First of all, do not violate the requirements of agricultural technology when growing, then even completely healthy plants can be brought to death. Use only healthy planting material without visible brown spots and rhizome decay. Propagate varieties with young daughter plants only from healthy bushes. All viral plants must be destroyed. Rotten fusarium plants should also be discarded in a timely manner, since all neighboring irises are quickly re-infected from the remaining infected plant debris and the disease becomes widespread. The most effective means for suppressing the further spread of fusarium (and gray) rot is the shedding of plants along the rhizomes and under the root with a 0.2% solution of the foundationol and pickling of individual rhizomes in this solution before planting for 30 minutes. The symptoms of bacterial rot on the rhizomes are usually removed (cleaned), wounds and cuts are etched with a strong solution of potassium permanganate, repeating such procedures constantly after prolonged rains. Against various spots before and after flowering, plants can be sprayed with 1% Bordeaux mixture or copper oxychloride (0.3%).
Of the pests, the most harmful to irises are Iris scoop, gladiolus trippe, bear, slugs, wireworm, hoverflies.
Iris and winter scoops. These are dangerous pests of bearded and especially Siberian irises.
At the beginning of the growing season, the caterpillars of the scoop (Hydraecia micacea) eat away at the base of the peduncles, which turn yellow and die off. They are unable to “cut off” the powerful peduncles of tall bearded irises however, the damage they cause is sufficient for the stalks to be blown down by the wind. In addition, caterpillars can damage rhizomes (Iris scoop (Helotropha leucostigma) and winter scoop (Agrotis segetum)), which are then easily affected by bacterial rot. In dry summers, iris plantings are more affected by scoops.
To combat this pest, at the beginning of the growing season, double spraying (with an interval of 7 days) with a 10% solution of karbofos is carried out.
Gladiolus thrips. This insect, barely visible to the naked eye, causes significant harm. The length of its tiny body is 1-1.5 mm. The trippe settles in tightly compressed leaf sheaths of irises. The affected leaf turns brown, dries, becomes covered with brown crusts. In such leaves, photosynthesis is disrupted, which adversely affects the development of the entire plant, the laying of peduncles and flowers.
To combat this pest, the affected plants are sprayed twice with a 10% solution of karbofos with an interval of 7 days. You can use tobacco infusion for spraying: insist 400 g of makhorka in 10 liters of water for two days, strain, add 40 g of laundry or green soap.
Medvedka in the south of Russia is a serious danger to irises. An adult insect reaches 3.5-5 cm in length. It has wings, strong movable horny jaws, strong front claws equipped with a toothed file, with which the bear cuts the soil, and with it rhizomes, roots, and bulbs. The pest travels easily underground, swims quickly in water and even flies through the air. Crawling to the surface of the ground, it moves quite quickly. The insect's “uniform” is durable and waterproof. The pest is endowed with a very delicate sense of smell. How to deal with a bear? 1. Collect more eggshells during the winter, crush them into powder. In the spring, when planting the plants, moisten the powder with vegetable oil for odor and put one teaspoon in the holes. Medvedka, having tasted the bait, dies.
2. Pour the pest's ground tunnels with soapy water (4 tablespoons of washing powder per bucket of water). Medvedka either dies underground, or crawls out to the surface, where it is easy to collect and destroy.
3. If you plant marigolds along the borders of the site, this will close the bear's access to your garden from the neighboring territory.
4. You can get rid of the bear with the help of infusion chicken droppings watering them on the ground in dry weather.
Slugs belong to gastropods. This is a common field slug (Agriolimax agrestis) and an agile slug (A, laevis). The pest is polyphagous, damages a wide variety of flowers, vegetables and other crops. The pest eats oblong holes in the leaves, can eat flowers. It multiplies strongly in rainy weather. It is nocturnal, hiding during the day under lumps of earth, large leaves, in other secluded places. The presence of a pest is indicated by the appearance of silvery mucus on the leaves. Leaf-eating caterpillars do not leave such marks.
Slugs primarily damage the more delicate central leaves of the leaf bundle. With a massive accumulation of pests, they damage other leaves. Of all types of irises, bearded ones are preferred. Slugs can contribute to the spread of bacteriosis. Leaf bundles that have fallen to the ground, affected by bacteriosis, are eaten by slugs with great pleasure. Then, crawling onto healthy plants, the slugs carry the causative agent of this disease.
To fight slugs, burdock leaves or wet rags are laid between the plants, which serve as shelter for them. Then the pests are collected and destroyed. You can use tobacco (shag) dust (4 g / m 2), superphosphate (35 g / m 2). Granular metaldehyde is a very good means of fighting slugs. The granules are scattered in dry warm weather in the evening or early in the morning between plants (30-40 g per 10 m 2).
May Khrushch. The beetle larvae gnaw at the roots and rhizomes of the irises. The larvae grow in the soil for several years. They can be found in large quantities in organic residues, in manure. Before introducing manure into the soil, it must be sifted through a sieve with sampling of larvae and their subsequent destruction.
Wireworm (click beetle)... Beetle larvae damage rhizomes, eating holes and passages in them, in which bacteria and fungi settle, and the plant may die over time. The clicker beetle has a small elongated black body, and striped specimens are also found. The larvae are narrow, long, segmented, with a very dense yellow or brown shell. In the winter they penetrate deeply into the soil, in the spring, with warming up the soil, they rise up. Deep digging of the soil contributes to the destruction of the larvae and the beetles themselves.
To combat insect pests, you can use and infusions of insecticidal plants: Red hot chilli pepper (100 g of cut fresh pods or 50 g dry) is poured into 1 liter of water and boiled for 1 hour, then kept for two days, after which the broth is filtered and the plants are sprayed at the rate of 100 g of infusion per 10 liters of water with the addition of 40 g of green soap.
You can also use pyrethrum - dust the plants with powder or infuse 100-200 g of powder for 10 hours in 10 liters of water and spray with this solution. When using insecticidal plants, as well as when working with pesticides, you must follow the rules of personal hygiene: protect your mouth and nose with a respirator, wash your hands thoroughly after processing.
DISEASES OF IRIS.
Irises can be affected by bacterial, fungal, viral diseases, although compared to other perennials, they are more resistant to the effects of pathogens.
The most dangerous disease of irises is bacteriosis, or soft rot of rhizomes. The causative agent of the disease is the bacterium Erwinia aroidea, or Pseudomonas iridis. Diseased plants lag behind in growth during the growing season. Their leaves turn brown and, starting from the tips, dry up. The affected fan of leaves bends down, leaves are easily pulled out of it, and eventually it falls to the ground. Affected stem bases emit an unpleasant odor. The rot spreads to the inside of the rhizome, which is completely destroyed, turning into a white, mushy, foul-smelling mass. The plant dies. The rhizome shell remains intact.
Freezing of korievisches, high humidity, thickening of plantings, lack of phosphorus and calcium in the soil contribute to the spread of rot. The introduction of fresh manure, excess nitrogen in the soil also contribute to the emergence and development of infection.
The disease is transmitted through bacteriosis-infected soil and plant debris. Pathogens enter the plant through mechanical damage formed during transplantation and loosening, as well as caused by soil insects (wireworms, beetle larvae).
To combat bacterial rot, diseased plants are discarded. When transplanting, the affected areas of the rhizomes are cut out with a sharp knife to healthy tissue and sprinkled with crushed coal. Before planting, the rhizomes are etched in a 0.5% solution of potassium permanganate for 30 minutes or in kaptap suspensions (0.2-0.5%) for an hour. Protect the rhizomes from freezing and mechanical damage. Destruction of insects - carriers of the disease is important. It is important to observe the culture turnover with the return of the irises to their original place in 4-5 years.
Fusarium, or fusarium rot. It is caused by mushrooms from the genus Fusarium. The disease begins with decay of the roots, inside which the fungus grows and clogs the conducting vessels with its mycelium. Brown rotten areas appear from the bottom of the rhizomes, the roots die off, and the rhizomes dry. This drying out is often called dry rot. If rot progresses during the growing season, then outwardly it looks like a rapid yellowing and drying of leaves and peduncles. On the surface of the affected rhizomes, a faint grayish-white bloom of mycelium is often noticeable.
Photo by L. Treivas from the magazine "In the world of plants" - 2002 - №6
Gray rot caused by two types of fungus. The first affects the stems and ends of leaves at high humidity. The leaves become discolored, then turn brown and rot, becoming covered with a gray bloom of fungal sporulation.
The second type of fungus causes dry rot of the rhizomes. On the affected rhizomes, black folded piles are formed, consisting of the sclerotia of the fungus. Rot can spread to the base of the leaves, where a gray coating of fungal spores forms. The development of the disease is facilitated by high humidity, excess nitrogen in the soil, mechanical damage and freezing of rhizomes.
For the prevention of gray rot, irises are recommended to be planted in well-drained, ventilated sunny areas. Avoid lack of phosphorus and calcium in the soil. Severely affected specimens are discarded. When symptoms of the disease appear, the plants are sprayed with fungicides. When planting, the rhizomes are etched, the affected areas are removed. It is necessary to disinfect contaminated soils.
Leaf spot, or heterosporiasis. This fungal disease affects irises in the second half of summer. Initially, the extreme, aging leafy bundles are affected. Whitish-gray spots with a yellow, slightly watery border are formed on them. Then the spots grow, small black dots of sporulation of the fungus appear on them. The affected leaves dry up. Then the disease spreads to the inner leaves of the bundle. Warm, humid weather promotes disease progression. Spotting sharply reduces the decorative effect of irises, but does not cause much harm to plants entering the dormant period.
Since the infected leaves serve as a reservoir of infection, important point in the fight against this disease is the destruction of plant debris and dried leaves. It is important to systematically remove aging leaves. When the first symptoms of damage appear, the plants are sprayed with copper and zinc-containing fungicides.
Ascochitosis leaves are caused by a fungus of the genus Ascohita. The spots are brown, without bordering, with numerous black punctate pycnidia.
Septoriasis leaves are caused by a fungus of the genus Septoria. The spots on the leaves are pale gray, with a brown border, small, rounded. Black pycnidia appear on the surface over time.
Ramulariasis leaves are caused by a fungus of the genus ramularia. The disease manifests itself as brown or even black small, rounded spots, which fade over time in the center. A weak yellowish bloom of the mycelium appears on necrotic spots.
Rust. The disease is caused by a fungus. On the leaves along the veins, dark brown small spots appear, covered with powdery fungal spores. The leaves soon dry up. The spores of the fungus overwinter on the affected leaves.
In order to combat this fungal disease, it is recommended to observe culture rotation with the return of irises to their original place in 3-4 years. It is important to destroy all affected foliage, plant debris, it is useful to mulch the soil. Feeding with phosphorus and potassium reduces the likelihood of disease. When symptoms of damage appear, the plants are sprayed with zinc and copper-containing preparations or a suspension of colloidal sulfur.
Photo from the magazine "Floriculture" - 2001 - №3
Mosaic- viral disease. On the leaves, a pattern is formed in the form of a grid or yellow stripes, reminiscent of a mosaic. Plant growth slows down, shortened peduncles are formed, flowers are underdeveloped. The flower petals become variegated. The carriers of the disease are aphids (Myzus persicae, Macrosiphum solonifolii, etc.).
If the irises are infected with viruses, they cannot be cured. Only preventive measures are taken. Good grooming helps mask the symptoms of the disease, but the plants will be a source of infection for the healthy. Timely culling of diseased specimens is necessary, as well as the fight against insects - carriers of viruses (aphids). In the photo on the left there is a streaky mosaic on iris leaves.
A.A. Karpov "Irises" / Rostov n / D: publishing house "Phoenix", 2001. - 96 p.
L. Treivas "Diseases of irises" // "In the world of plants" - 2002 - №6
Signs of the disease. Elongated grayish-brown spots with a darker border appear on the leaves. With a strong development of the disease, the leaves dry out. The disease does not spread to the rhizome.
Control measures. Destroy plant debris and dried leaves. Spraying with cuproxate is applied. Plants are treated with copper-containing preparations, for example, a suspension of copper oxide (0.3%) or Bordeaux liquid with the addition of adhesives. Bordeaux liquid (1-1.5% solution) can be prepared independently: 100 g of copper sulfate and 75 g of slaked lime per 10 liters of water. The soil around the plants is also spilled with a solution of copper-containing preparations. Spraying with fungicides is also effective. It must be remembered that you need to use only those drugs that have received permission for use in personal subsidiary plots. Combined treatment combines protection against heterosporia and harmful insects.
Prevention. To increase the resistance of irises to this disease, spring spraying of the leaves with a solution of calcium chloride or calcium nitrate is carried out. Calcium helps to increase the strength of the cell walls, and thus, plants become less susceptible to disease.
To protect against leaf spots that progress in rainy weather, preparations of a new group of strobilurins (synthetic analogs of the waste products of some fungi), such as strobes, are very effective, the peculiarity of which is that they are not washed off by rain for an extended period of up to two weeks. However, strobilurins should not be used more than twice a season and should be alternated with contact agents such as copper oxychloride. Strobilurins, like contact fungicides, have only a protective effect. They do not destroy pathogens, so they must be used before the spread of diseases.
Rust
, the causative agent is a mushroom Puccinia iridis.
Signs of the disease... In late summer - early autumn, brown stripes appear on the leaves, which, when touched, leave rusty dust on the finger. Affected leaves dry out prematurely.
Control measures... Large plant residues are destroyed, small ones - they are embedded in the soil during its processing or the areas are mulched with peat, humus or sand with a layer of 2-3 cm. In this place, irises can be planted no earlier than 3 years later. Spraying with copper oxychloride, cuproxate (1%), colloidal sulfur with adhesives is used.
Prevention... The resistance of plants to rust is increased by phosphorus-potassium supplements. The disease can be prevented by sprinkling the plants with Bordeaux liquid in the middle of summer.
Wet , or bacterial, rot, bacteriosis ; pathogens - bacteria Pectobacterium carotovorum, Erwinia aroidea, Pseudomonas iridis. This disease affects bearded irises and especially often develops when plants are grown in conditions of high humidity, on heavy soils, with deep planting of plants and with freezing of rhizomes.
Photo by L. Treivas from the magazine "In the world of plants" - 2002 - №6
Signs of the disease... The leaves turn pale, and then dry up and turn brown. A fan of leaves tilts and then falls to the ground. Rhizomes and leaf bases darken, decompose, turning into a mushy, unpleasantly smelling mass. Plants die.
Control measures... The plant is dug up, its aboveground part is destroyed, the soil around is loosened and treated with a solution of a permitted fungicide. The rhizomes are cleaned to healthy tissue, the sections are washed with a strong solution of potassium permanganate and covered with Novikov's liquid (brilliant green with glue) or sprinkled with crushed charcoal or ground sulfur. The causative agent of rot dies in direct sunlight, so the cut can be dried in the sun. Plants are transplanted to another site. When transplanting, the rhizomes are washed in a solution of formalin (1: 300) or quinosol (0.2%). Effective method fight against wet rot is also soaking the rhizomes in a 0.01% solution (1 tablet per 1 liter of water) of the antibiotic tetracycline for about 1 hour. First, the rhizomes must be dried in the sun - then they better absorb the drug. Prevention. It is possible to prevent the occurrence of this disease by observing the rules of iris agricultural technology. The main thing is not to overmoisten the plantings of irises and make required amount phosphorus and potash fertilizers. As a preventive measure, you can also spray on green foliage with a solution of urea with the addition of sulfur (12%), permitted fungicides or sodium thiosulfate solution (neutral photographic fixer), which decomposes in the soil to form sulfur.
Preventive measure, effective in years with humid summers, are watering the soil with solutions of antibiotics: tetracycline or streptomycin sulfate (agrimycin), which are prepared by diluting 30 g of the antibiotic in 10 liters of water. 60 liters of solution are poured onto 1 m2 if the soil is coarse-grained, and 80 liters if the soil is fine-grained. Watering is carried out every 10 days.
Gray rot, botrytis
; causative agent - mushroom Botrytis cinerea... The disease is caused by two types of fungus. The first affects the stems and ends of leaves at high humidity. The second type of fungus causes dry rot of rhizomes. The disease develops in conditions of high humidity, with an excess of nitrogen in the soil, with freezing of the rhizomes and the presence of mechanical damage. 
Affected plant
Photo by L. Treivas from the magazine "In the world of plants" - 2002 - №6
Signs of the disease... Peduncles and leaf tips become discolored, and then turn brown, rot, become covered with a smoky gray coating of the fungus. Black folded piles consisting of sclerotia of the fungus form on the affected rhizomes. Rot can also spread to the base of the leaves, where a gray coating of fungal spores forms.
For prevention gray rot irises are recommended to be planted in well-drained, ventilated sunny areas. Avoid lack of phosphorus and calcium in the soil. Severely affected specimens are discarded. When symptoms of the disease appear, the plants are sprayed with fungicides. When planting, the rhizomes are etched, the affected areas are removed. It is necessary to disinfect contaminated soils.
Scorch
, the causative agent is presumably mycoplasma.
Signs of the disease... The leaves turn brown in the middle of the growing season, their ends, drying out, bend, the roots die off, the rhizome hardens and dries up.
Control measures... Plants are usually dug up and destroyed, and the soil is treated with lime or formalin.
Prevention... Sometimes the affected bushes are restored in the second or third year from dormant buds, but the main preventive measure of this disease is the advance division (cutting) of the bushes into several unconnected parts. In this case, a transplant is not necessary. Scorch is not transmitted to neighboring, already isolated plants.
Ascochitosis leaves are caused by a fungus of the genus Ascohita. The spots are brown, without bordering, with numerous black punctate pycnidia.
Septoriasis leaves are caused by a fungus of the genus Septoria. The spots on the leaves are pale gray, with a brown border, small, rounded. Black pycnidia appear on the surface over time.
Ramulariasis leaves are caused by a fungus of the genus ramularia. The disease manifests itself as brown or even black small, rounded spots, which fade in the center over time. A weak yellowish bloom of the mycelium appears on necrotic spots.
Mosaic - viral disease. On the leaves, a pattern is formed in the form of a grid or yellow stripes, reminiscent of a mosaic. Plant growth slows down, shortened peduncles are formed, flowers are underdeveloped. The flower petals become variegated. The disease is spread by aphids.
Photo from the magazine "Floriculture" - 2001 - №3
If irises are infected with viruses, they cannot be cured. Only preventive measures are taken. Good care helps to mask the symptoms of the disease, but the plants will be a source of infection for the healthy. Timely culling of diseased specimens is necessary, as well as the fight against insects - carriers of viruses (aphids). In the photo on the left there is a streaky mosaic on iris leaves.
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