Unfortunately, phloxes get sick and are affected by pests. They have the same diseases as other flowers and the same pests. The main diseases are fungal and viral. Often we ourselves are to blame for the appearance of diseases: we do not follow the rules of agricultural technology, we do not engage in prevention. It is wiser to plant new plants in a quarantine bed. Once you're done with one plant, train yourself to disinfect your garden tools (pruning shears, knife, scissors) and even your own hands.
Viral and mycoplasma diseases
Viral and mycoplasma diseases cause great harm to phlox. They are not treated, diseased plants must be destroyed. Signs of viral diseases are: leaf mosaicism, annular spotting, dying off of individual parts or organs of plants, dwarfism of plants, crushing of leaves. Sometimes deformation of the leaf blade is observed, it becomes narrow, wrinkled, pitted and tuberous. Fortunately for us, these diseases are quite rare.
Most viral diseases are transmitted mechanically or by sucking insect pests. The fight against viral diseases consists mainly of preventive measures: the destruction of insects that carry viruses, the identification and destruction of diseased plants, and the disinfection of garden tools. There are no effective measures to combat viral diseases. Usually, the disease affects the entire bush, which is recommended to be dug up along with the ground and removed from the site. The fossa should be etched with formalin or chlorine-containing compounds (for example, the household drug "Whiteness").
Variegated - the most common and dangerous disease of phlox, which is characterized by the appearance of light chaotic stripes on the flowers, expanding to the edge of the petals. This disease is especially clearly visible on dark phlox. The disease can even be on one inflorescence, but this does not make it less dangerous, the diseased bush must be immediately destroyed, because insects can easily transfer this disease to other plants. The causative agent is a rash mosaic virus. This pathogen has a wide range of host plants and from flower crops it affects carnation, delphinium, and tulip. The disease is spread by nematodes of the genus Xiphinema and insects.
You need to know that there are phloxes with shading along the petals (Traces, Katenka-Katyusha), but the shading of such phlox is not chaotic and does not expand towards the edge of the petals. There are, unfortunately, foreign varieties with chaotic stripes, but there are few such varieties: Bauernstolz, Forster and Picasso.
Several times I saw pictures of sick phloxes offered for sale on the Internet. Sometimes they bring similar plants to our phlox exhibition to determine the variety.
Mycoplasma organisms, like viral, are causative agents of a number of diseases such as jaundice, deformities, sterility, etc. The carriers of mycoplasma are cicadas. The fight against mycoplasma diseases comes down to prevention: vector control, agrotechnical measures, the use of healthy planting material.
The greatest harm to phlox is caused by the causative agent of jaundice asters - a parasitic mycoplasma organism. The host range of this disease includes about 200 plant species. The disease on phlox has a rather long incubation period, up to 60 days, so it can appear the next year after infection. Phlox leaves are strongly discolored, strange yellow-green flowers appear, which makes it possible for illiterate phlox breeders to pass them off as new, unusual seedlings. But in fact, these "masterpieces" should be immediately destroyed.
The most dangerous pest of phloxes is the phlox race of the stem nematode Ditylenchus dipsaci var. phloxidis... This is a small translucent worm that settles mainly in the stems of phlox and feeds on their juice.The development cycle lasts from several days to several weeks, depending on the air temperature and humidity. The optimum temperature, conducive to the reproduction of nematodes, is 18-240C, and at temperatures above 400C, the nematode and its eggs die. Therefore, today the main way to fight the nematode is thermal... But this method is not suitable for phloxes, its divisions do not survive after being treated with hot water.
The insidiousness of the disease lies in the fact that in the early stages it is rather difficult to distinguish a diseased plant from a healthy one; signs of nematode damage are clearly visible only in late June - early July. The main feature is the threadiness of the apical leaves, thickening of the stems, the plant becomes as if squat. Sometimes sick phloxes even bloom, but the inflorescences look pretty ugly. If a nematode infection is detected, first of all, watering the plants from above should be excluded, it contributes to the rapid spread of the disease, especially in warm weather.
A heavily affected plant dies. Not only phloxes, but also other plants suffer from stem nematodes. In nature, the nematode infects 400 plant species, it has the strongest digestive glands. In general, the nematode is the scourge of phlox. The developers of plant protection products have not yet offered anything radical to combat this disease in personal subsidiary plots. The nematicides allowed for use in farms are so dangerous that I will not even give their names, so as not to take a sin on my soul.
In the literature, it is recommended to cut the upper parts of the shoots in May to improve collections and save valuable varieties. The studies carried out at present allow us to conclude that early spring cuttings or harvesting cuttings in the fall in order to improve the varieties should be carried out at soil temperature less than 100C... Analyzes of phlox stems for nematodes in spring show that nematodes are not yet present in stems 5 cm high. The nematode is already present in the lower part of the stem at a height of 6-7 cm, but it is not yet present in the apical part. At such a height and a soil temperature below 100C, you can cut the tops of phlox in spring in order to preserve the variety and get rid of the nematode. When the stem height is 9-10 cm, the nematode has already reached the top of the phlox.
The most effective way to control a nematode is to manually cull the plants. Regularly inspect your plantings, you saw one or two diseased stems in the bush, immediately break them as close to the roots as possible, and in - a fire.
Peas, mustard, parsley, dill, marigolds, calendula are trapping plants. They accumulate the nematode. Alternate planting phlox and marigold. In the fall, carefully dig up the marigolds with roots and burn them. It is even better to sow dill between phloxes, nematode and other diseases infestation is sharply reduced. Dill can be eaten or seeds can be collected from it, the nematode does not harm people. Weeds are nematode accumulators, so try to keep dandelion, thistle, nettle, woodlice out of phlox plantings. Slugs eat diseased leaves, and secrete a nematode.
Nematoda does not live in the ground. Its larvae are surprisingly tenacious. They hibernate in regeneration buds, at the base of shoots, in rhizomes and in dry plant debris. Therefore, in the fall, you need to carefully clean the beds. In the spring, nematodes penetrate the growing stems and together with them rise upward, affecting the plant.
Phlox fungal diseases
Fungal diseases can be caused by:
- the effect of the pathogen on the leaves, the result is various spots, rust, powdery mildew. Leaf spots are named after the pathogens that cause diseases: Alternaria, phyllostictosis, cercosporiasis, septoria, rust on the leaves is caused by rust fungi;
- the effect of a pathogen on leaves, stems, buds, flowers, causing a disease with gray rot, or botrytis;
- the effect of the pathogen on the root collar and the base of the shoots, as a result - the disease with phomosis (dry rot);
- the effect of the pathogen on the roots, causing verticillary wilting, fusarium.
Spots, rust, powdery mildew... From mid-July, dots or small spots of various colors may appear on the leaves of phlox (red - rust colored, dark brown, brownish, etc.). They gradually increase in size, the leaf dries up and dies off. These are signs of phlox disease leaf spot (alternaria, phyllostictosis, cercospora, septoria) or rust, diseases caused by parasitic fungi. Rust is a particularly dangerous disease, due to the ease of its spread, the disease manifests itself as yellow-orange powdery spots on the leaves and flower stems. The causative agents of the disease develop in the aerial parts (leaves, stems, flowers) and feed on plant cells. As a result, an infected plant increases the evaporation of moisture, disrupts the water balance, metabolism, reduces the ability to photosynthesis, slows down growth and deteriorates the quality of seeds. Intense rust usually leads to the death of the plant. At the same time, the causative agents of the disease have time to move to healthy crops. Billions of rust fungus spores ripen on one plant. Spores are easily carried by the wind, not only from tree to tree or from garden to garden, but also over very long distances. The development of the disease in crops growing in open ground is facilitated by increased air and soil humidity, high temperature, and wind. The appearance of the disease is "helped" by an excess of nitrogen and a lack of potassium in the soil. Rust does not tolerate severe frosts, but can retain its spores in a thick layer of mulch during warmer winters. The optimum temperature for the development of the disease is 24-280C and the relative humidity is about 85%.
And in August, the leaves may appear powdery mildew... On the leaves, and then on the shoots and inflorescences, you see grayish-white spots, first in the form of separate dots, which then merge and appear in the form of a powdery coating. Examine the plants carefully so as not to miss the onset of the disease. It spreads very quickly and you have a very short period of time to take action. Humid air, temperature fluctuations, the proximity of plants that easily fall ill with powdery mildew, contribute to the disease.
Gray rot, or botrytis, caused by the mushroom of the same name Botrytiscinerea. Leaves, stems, flowers, buds are affected, growing spots appear on them. Massive damage to plants most often occurs when the air temperature drops to 15-18 ° C, and the humidity rises. Spores, together with moisture, settle on the leaves, stem and flower, germinate and penetrate into plant tissues. The infection spreads from top to bottom - from the leaves and stems, it penetrates the bulbs or roots of the plant.
Peonies are especially affected. Wet weather and excess nitrogen contribute to disease. I come to my neighbor with a friendly visit, the hostess left, and there ... poor peonies. I divorced Alirin with Gamair in maximum concentration and processed the bushes. Everything! The pions recovered, and by the time the hostess arrived, everything was in order. Therefore, prevention and prevention again.
Fomoz... This disease is caused by a parasitic fungus. Phomaphlogis... A symptom of the disease is premature curling and drying of leaves on the lower parts of the stem. The leaves dry out, then the shoots are affected, they become fragile, brittle, easily cracked, the bush lags behind in growth, and the source of the disease is damage to the root collar.
It is necessary to distinguish phomosis from physiological drying of the lower leaves and cracking of the stems, which is often seen in phlox. This is due to an imbalance between the amount of water consumed by the aboveground part and the amount of water supplied by the roots. The shrinking of the lower leaves is not a disease, but a physiological process.In spring, with a sufficient supply of moisture, the stems and leaves develop quickly. If at the beginning of summer there is no rain or watering of plants is not done, the leaves begin to dry out. The same phenomenon in phlox is observed with a late spring or summer transplant. Abundant and regular watering significantly reduces this phenomenon. Drying of the lower leaves in plants can occur as a result of inept or improper watering them with solutions of mineral fertilizers. It must be remembered that the plants should be fed with liquid fertilizers in the evening hours or in cloudy weather only after watering, followed by spraying the lower leaves with clean water. On well-fertilized, but insufficiently moist soils, leaf drying is observed to a greater extent than on unfertilized soils. This is due to the fact that the lack of moisture in the soil creates a high concentration of soil solutions, which has a depressing effect on the plant.
On some varieties of phlox, longitudinal cracking of the stems is observed from late May to early July during the rapid growth of plants. A similar phenomenon occurs more often in humid warm years with one-sided nitrogen nutrition of phloxes from spring, lack of lime in the soil, and thickening of plantings. Thus, stem cracking is not a disease, but a physiological phenomenon. With timely liming and the introduction of complete mineral fertilization, cracking of the stems is less common. In shaded areas, phlox bushes need to be planted rarely to ensure air circulation between them. You should not water the bushes with cold water during the day and in hot weather.
Verticillary wilting of stems occurs most often on acidic soils and in humid places. The disease is caused by the fungus Verticilliumalbo-atrum... A sudden wilting of leaves and a fall of shoots begins. The soil pathogen, through small damage to the roots, penetrates the vascular system of the phlox, clogs and poisons it. Outwardly healthy shoots wither and die off. The mycelium grows on the surface of the infected roots as a whitish plaque that then turns reddish-brown. The disease is focal in nature, most often manifests itself on acidic soils at a temperature of about 25-270C. The pathogen is surprisingly tenacious, retains its activity in the soil for up to 15 years.
For the prevention and treatment of the disease in the initial stage, use Glyocladin (d.v. - Trichoderma harziannum). This microbiological fungicide effectively inhibits fungal diseases in the soil: root rot, wilting of various etiologies, verticillosis, late blight. The drug is produced in the form of water-insoluble tablets, shelf life is 2 years. Moisten the ground around the plant, place one or two tablets (depending on the size of the plant) near roots, mulch with organic matter and maintain moisture for at least a few days. The drug works well at a humidity of 60-80% and a temperature of 14-27oС. Trichoderma forms a well-developed mycelium in the soil, is a competitor and antagonist of phytopathogenic fungi. High activity leads to growth arrest and death of pathogenic fungi. If you are using the drug for the first time, it is advisable to use it twice a season - in spring and autumn. After healing the soil, you can switch to a single application. Similarly acts Trichocin - a water-soluble analogue of Glyocladin.
In case of mass death of phlox, diseased bushes should be carefully dug up together with the soil, shake off the ground, cut off the stems, immerse the roots of the bushes and the lower part of the stems in a solution of such drugs as Maksim or Vitaros... Treated bushes are planted in a new place, covered with cut plastic bottles.
Preventive treatment of existing plants must be started in spring and done systematically, i.e. not once, but several times at regular intervals.
In protecting plants from phytopathogens, modern science is increasingly turning to the mechanisms that allow plants to survive under the influence of numerous stress factors of abiogenic and biogenic nature. And here we will be helped by substances called resistance inducers, or immunomodulators, which can induce resistance to diseases and activate the course of protective reactions. Currently, there are many such drugs known. I list the most affordable ones - Fitosporin, Alirin, Gamair, Ekogel, Immunocytofit, Amulet, Novosil (Silk), Zircon, Domotsvet, HB-101. The practical use of drugs for inducing resistance to phytopathogens, with all their apparent safety, requires compliance with certain rules. When preparing solutions, the recommended dosages must be strictly observed; exceeding the concentration can lead to the opposite effect. The drugs used must be of good quality, so keep track of the expiration dates and buy drugs from well-known companies. Apparently, you should not use these drugs all the time. And, of course, if the rules of agricultural technology are not followed, even the most modern drugs will not help.
To prevent diseases, the processing of planting material is recommended, especially if you buy imported phlox.
Preventive treatment of planting material
For the prevention of planting material, you can use such well-known dressing agents as Maksim and Vitaros.
Vitaros (d.v. carboxin + thiram) has a systemic contact effect, suppresses infection both on the surface of the planting material and inside it. By moving to the points of growth, the preparation protects seedlings and the root system of plants from damage by soil pathogens. Planting material of flower cultures is etched before planting by immersion in a 0.2% working solution with an exposure of 2 hours.
Maksim(a.v. fludioxanil) is a contact fungicide to protect not only phloxes, but also any planting material (bulbs, corms, potatoes) from rot during storage and before planting. Maxim kills only pathogens, preserving the beneficial microflora of the soil, which is very important for soil fertility and plant health. Processing is carried out by immersion in a 0.2-0.4% solution with an exposure of 30 minutes, followed by drying (2-4 ml / 1 l / 30 minutes). Maxim shows a protective effect during the entire period of growth or storage. The drug is also interesting because it not only protects plants from diseases, but also strengthens their immunity, stimulates growth. Provides long-term protection against various root rot. This preparation can also be used for spraying roots and rhizomes after dividing bushes and before planting.
Biological fungicides are also suitable for this purpose - Alirin with Gamair.
Alirin (d.v. Bacillus subtilis 10-VIZR) is a microbiological fungicide against fungal diseases of plants. Effectively suppresses: root rot, septoria, rhizoctonia, late blight, alternaria, cercosporosis, trachomycotic wilting, powdery mildew, downy mildew, scab, moniliosis, gray rot, rust. Gamair (d.v. Bacillus subtilis M-22 VIZR) is a microbiological bactericide against bacterial plant diseases. Effectively suppresses fungal and bacterial diseases: bacterial cancer of tomato, necrosis of the pith of the stem, soft rot and a wide range of fungal phytopathogens.
The preparations can be used for soil cultivation, seed soaking and spraying of plants during the growing season. They are available in the form of tablets, soluble in water, the shelf life is quite decent, 3 years.
The planting hole is best shed with fertilizer. Barrier, which contains microbiological preparations Azobacterin and Extrasol.Azobacterin contributes to the restoration of soil fertility, stimulates the regrowth of shoots, the development of the root system, and increases the turgor of the leaves. Extrasol has a growth-stimulating and fungicidal effect.
The best result is obtained by complex treatment of plants with biological fungicides before planting, then 2-3 times during the growing season. Before planting, hold the cuttings in a solution of Maxim or Vitaros, rinse in water, then 1-2 hours in a solution of Alirin and Gamair (1t + 1t / 1 l of water). Very good biological product Ribav, I especially recommend its use if the plants are weak. After rooting and starting to grow, place the Glyocladin tablet near the roots or spill with Trichocin.
If, nevertheless, the plants get sick, I advise you to start treatment with biological fungicides Alirin and Gamair. They work well together. We begin treatment with a concentration of 3 tablets of Alirin + 3 tablets of Gamair / 1-1.5 l of water, after a week we increase the concentration to 4-5 tablets. Alirina + 4-5 tab. Gamaira / 1-1.5 liters of water.
If biological products do not help, it is necessary to switch to systemic chemical fungicides approved for use in private household plots: Topaz (d.v. penconazole), Speed (d.v. difenoconazole), Forecast (d.v. propiconazole).
Skor's analogues - Discor, Planthenol, Raek, Chistotsvet. Forecast analogs - Propi Plus, Pure Blossom BAU. Most effective against various types of spotting, rust and powdery mildew while the Forecast is working.
There are certain rules for the use of chemical fungicides that are not recommended to be violated.
- Processing should not be one-time. The properties of systemic fungicides are fully manifested during the block treatment: carry out at least two treatments in succession, one after the other. The maximum frequency of application per season is three.
- Spray only young, actively growing plants. At this time, they well absorb the systemic component of the fungicide, it quickly moves inside the plants and is redistributed to all their parts, providing maximum protection against infection.
- The intervals between treatments should be a maximum of 14 days. Only after two treatments with a systemic fungicide can you start protecting with contact fungicides, taking into account that the interval between treatments with these preparations is shorter (7-8 days).
- Be sure to write down which drugs you are using. Do not use the same fungicides all the time. The next year, the drugs need to be changed, but for a different chemical group. It makes no sense to change Topaz to Speed or Forecast, they belong to the same class of triazoles.
The key to success in growing phlox, like any plant, is in healthy planting material and proper care.
Phlox Bauerstolz and Picasso - from the book B.H. Bendtsen "Phlox".
Drawing of a nematode - from the book "Applied Nematology", Moscow, publishing house "Science", 2006