Stagonosporosis - red burn of hippeastrum and amaryllis
One of the most dangerous diseases for indoor hippeastrum and their relatives is stagonosporosis. True, he is familiar to most gardeners under the name of a red burn. This disease very often leads to the death of the plant, because it not only severely affects the tissue of the bulbs, but also spreads rapidly. You need to deal with the disease quickly and radically.
Amaryllis Red Rot
Stagonosporosis, red burn, or red rot - one of the most "highly specialized" diseases in indoor plants is the defeat of plants by the fungi of stagonosporosis, which threatens only Amaryllis, and even then not everyone. Most often, a red burn occurs in two types - hippeastrum and genuine amaryllis. But it is not so rare that stagonosporosis occurs on eucharis, a magnificent Amazonian lily, and on clivia with its delightfully large inflorescences. And today, imported varieties of other representatives of this family are also increasingly suffering.
Not recognizing this disease is very difficult. After all, the name itself - “red burn” - directly indicates its main distinguishing feature. Stagonosporosis manifests itself in the appearance of red-orange spots and narrow bands. They seem to be scattered on the surface of the bulb and resemble paprika in color. They appear unevenly, but thanks to the bright color they are easily recognizable, even if we are talking about very narrow stripes. But to see a red burn on the bulb, it must be out of the soil, and for already planted plants, a full-fledged diagnosis requires digging and examining the bulbs.
On dug bulbs or when buying, two more unchanging features of this disease can be noted:
- the bulb has very weak roots;
- flakes exfoliate, constantly dry.
But other signs are much more obvious and will tell you that the bulb is infected if you have already planted it and the plant is developing or blooming:
- leaves, peduncles and buds are covered with bright red strokes, not typical for the selected variety;
- the plant is poorly, slowly developing;
- flowering is weak and deformed (loss of flowering quality is characteristic even at a very mild stage of damage);
- the plant does not form new daughter bulbs, and those that already appear are very quickly affected by the fungus;
- the more neglected the problem, the more the leaves become deformed, and the flower stalks bend and wilt.
If the disease is not identified in time, stagonosporosis progresses and the nature of the lesion changes: a black pycnidia crust appears on red spots and strokes, from which spores spread around the plant, infecting neighbors and young leaves. And the red burn itself captures more and more new parts of the plant and damages the bulbs more and more, resulting in the decay of tissues and the death of the entire bulb.
Mindfulness - the best protection against red burns
The most important (and dangerous) source and factor of stagonosporosis is an inattentive purchase. Most often, the plant becomes infected before it even gets into your home. And almost never the manifestations of stagonosporosis are random or spontaneous. That is why it is so important not to ignore the opportunity to inspect the bulb with all due care. Bulbs of hippeastrum and amaryllis, eucharis or clivia should be examined from all sides and notice the slightest signs of any red spots. Healthy planting material is the main, defining measure to combat a red burn.
The development and spread of stagonosporosis is affected not only by the “initial” infection of plants, but also by several very dangerous factors:
- constant temperature fluctuations, especially sharp changes;
- too abundant watering, damp soil, stagnation of water in pallets;
- insufficient lighting;
- bulb injuries when planting or carrying;
- lack of access to fresh air.
So, and in this regard, mindfulness, this time, to care is the best preventative measure. If you take care of the plant correctly, maintain optimal humidity and check the degree of drying of the soil between irrigation, drain the water from the pallets on time and strictly observe the recommendations for a temperature range that is comfortable for the plant, stagnosporosis will not have a single chance.
All newly acquired bulbs, some growers recommend for the prevention of etching in a solution of systemic fungicide. And this is not a bad strategy.
The fight against stagonoporosis
This disease requires cardinal methods of control. And the matter is not only in the emergency digging of the onion, because most often they are treated with the treatment before the bulb goes into the dormant phase. In addition to urgent removal of it from the substrate with washing and other traumatic procedures, it is necessary to cut the bulbs themselves, removing all damaged areas. And there are simply no other means of struggle.
Whether you need to urgently take out the bulb or wait - it's up to you, focusing primarily on flowering. If your flowering is severely affected, it is better not to delay the transplant and carry out this procedure urgently. If the plant blooms without much damage, then watering is drastically reduced for it to quickly translate into a dormant phase, visible damage is treated with copper-containing preparations and preventive spraying with fungicides is carried out. And the full processing is carried out later, during the excavation.
In order to cope with a red burn, it is necessary to methodically process the bulbs step by step:
- The bulbous plant is isolated from other members of this family and the house collection as a whole to prevent the spread of volatile spores.
- If the bulb does not lose leaves or you are conducting an emergency transplant, all leaves with at least one stagonosporosis spot are cut off from the plant. The rest should be cut, but it is better to completely remove all the greens.
- The plant is removed from the pot, freeing the bulb and roots from the soil. For complete cleaning, the plant is thoroughly washed.
- All old flakes are completely removed from the bulbs, freeing the bulb itself for inspection and cleaning.
- Armed with a sharp knife, they cut out all the spots and red stripes, removing even their smallest traces.
- They do the same with roots: they remove not only all damaged, but also dry, injured, sluggish or “doubtful” areas. If there is a stain on the bottom, clean it too.
- Cropped bulbs without drying the slices are treated - etched with the main enemy of the pathogens of stagonosporosis - copper-containing drugs or fungicides.
For processing bulbs suitable:
- copper oxychloride or rubigan (drug concentration - 3-4 g per 1 liter);
- Bordeaux liquid with a concentration of 1%;
- copper sulfate with a concentration of 0.5-1%;
- sulfur preparations are also very effective, but it is undesirable to use them indoors and for indoor plants it is better to exclude them;
- systemic fungicides (especially if they can be applied to the bulb not with an aqueous solution, but in powder form); pay attention that the spectrum of their action includes an antispore-forming effect.
- Bulb processing should be carried out very carefully, with gloves, preventing the product from getting on the skin. The duration of the procedure is from 7 minutes to half an hour (the more serious the lesion, the longer the treatment). But it is better to always be guided by directions to a specific drug. Drugs are never washed off the bulbs, leaving them after etching as is.
- Preparation for planting boils down to only sprinkling cuts and cuts with chalk or crushed charcoal. It’s more efficient not just to sprinkle the slices, but to cook the pulp, “putty” from chalk and Bordeaux liquid, which is applied to the lesions.
- The bulb is dried for 3-7 days.
- Bulbs are planted in fresh (new) soil and in as tight containers as possible (distance to the walls - no more than 1.5 cm). For planting bulbs after pickling with copper-containing agents, it is advisable to use a ready-made purchased substrate. But if you make up the soil yourself, you can use it. Strictly observe the depth of planting and try to leave at least half, and it is better to leave most of the bulbs above the soil, so that at the slightest sign of the appearance of new red spots, treatment can be carried out.
- At first, protect plants from direct sunlight, temperature extremes, waterlogging, watering very carefully. To prevent the reappearance of red spots, it is advisable to spray or water the system with a systemic fungicide in standard concentration for another month or longer.
All copper-containing preparations and slurry for processing incisions can be used before excavation - lubricating damaged areas and spots in order to inhibit the development of the disease and its spread before further measures are taken. When red spots reappear in areas towering above the soil, they are treated without digging with the same means used to etch.
What to do if you bought a bulb infected with stagonosporosis?
If you bought bulbs “in absentia” or simply could not notice the traces of a red burn, then do not rush to throw out the bulbs: you can still try to save them. First of all, you need to carefully inspect the entire "batch" and be sure to isolate the damaged plants, and only then proceed with processing. And there are several processing methods for this:
- Lubricate the spots with gruel from chalk or Bordeaux fluid.
- Treat the spots with iodine and observe how the situation develops.
- Etch the bulbs in copper preparations or fungicides.
- Remove spots and streaks and carry out the treatment in the same way as for dug affected bulbs.
After processing the bulbs, it is necessary to dry them within 3 to 4 days before planting (if planting is carried out early, then they are left under observation in conditions convenient for storage). When planting, the bulbs are not buried in the soil, leaving a large part on the surface, so that it is possible to check and inspect the bulbs and carry out repeated treatments for stagonosporosis.
In appearance, healthy bulbs that were acquired along with the affected ones are better to prophylactically also etch in the systemic fungicide.