Often gardeners are prone to the misconception that diseases affect celery less often than other umbrella plants.
At the same time, non-compliance with the requirements of agricultural technology, combined with ignoring prevention, sharply reduces the immunity of plants. This makes them defenseless against attacks by aggressive microorganisms.
Although celery bushes suffer from many ailments, most likely, on your site you will have to face one of the diseases described below:
Powdery mildew. Two factors contribute to the spread of this insidious disease of all umbrella plants – moisture and heat.
The first sign is the appearance on the vegetative organs – leaves, shoots, peduncles – whitish or gray spots. They represent the sporulation of the fungus.
Gradually, the affected areas grow and merge with each other, weakening the plant more and more. As a result, the yield of root celery drops sharply, and the greenery of petiole or leaf celery completely loses its juiciness, taste, and presentation.
White spotting (septoria) is equally dangerous for celery and parsley, beloved by everyone. Most often, it appears focal in the form of tiny chlorotic spots on the underside of the leaf and shoots of plants.
Over time, spots grow to a diameter of 3-5 millimeters, turn pale. A brown border is formed along their edges, and in the middle – countless pycnidia points – the fruiting bodies of the pathogen. It happens that the spots acquire a brown color and do not have a pronounced border.
In advanced cases, the leaves begin to turn outward and dry out, and the petioles break off. Without the aerial part, celery roots cannot fully develop. And they become unsuitable for long – term storage.
It is also forbidden to collect seeds from diseased plants since they always turn out to be infected with mushroom picnics.
Alternariosis. You can recognize the disease by the black and brown spots of irregular shapes that appear on the stalks and petioles of celery. On the roots of plants, the skin begins to die, as a result of which they cease to absorb water and die.
During storage, the roots often show signs of black rot, which soon leads to damage and softening of all tissues.
Cercosporosis affects the entire terrestrial part of celery plants. Numerous shapeless spots appear on both sides of the sheet plate.
At first, they are yellow, but then turn brown. In the center, they become paler, and on the edges are convex. In conditions of high humidity, a thin gray coating forms on the lower sides of the leaves – the fruiting of the fungus.
In the phase of the most active sporulation, it begins to acquire a purple hue.
In wet summers, cercosporosis develops so much that the leaves from green turn into brown and quickly die off. In this case, the final death of celery is simply inevitable! The disease most often affects plants grown in low-lying, humid, and insufficiently drained areas.
Late burn of celery is a formidable disease, which often strikes at plantings of this crop in dry years.
As a result, numerous small, about 2 millimeters in diameter, rounded, yellowish spots form on the leaves of plants. The central areas of spots are quickly covered with a dark plaque from the fruit bodies of the fungus.
Sick leaves twist into tubules and eventually dry out. From the disease, leaf and petiole celery usually die, and their root counterpart sharply decreases productivity, and root crops lose their keeping quality.
Cucumber mosaic refers to a viral type of disease, causing a halt in plant development and severe deformation.
If you notice extensive chlorotic rings on the celery, encircling the stems and leaves and focal yellowing, most likely you have come across this infection.
The aphid is the carrier of cucumber mosaic, therefore its first signs usually appear during the mass flight of this insect. The pathogen lives on perennial cultivated, wild and weedy host plants, from where aphids spread.
Stolbur is another viral disease characterized by leaf chlorosis in the lower part of celery plants. Subsequently, the leaves acquire a reddish tint.
Celery, struck by a column, has the property of throwing a peduncle in the first year of vegetation. Root crops quickly lose their elasticity and deteriorate in the first two months after harvesting.
Not all celery diseases are viral or fungal in nature – plants also suffer from a lack of macro- and microelements. They react especially sharply to a lack of boron.
With boric starvation in plants, dying of growth points in the middle of the bushes is observed. Longitudinal cracks appear on the lower part of the petioles. On the roots, obvious signs of necrosis are also visible – microdamage in which microorganisms hostile to the plant settle. Celery is in great need of boron in dry periods and if plantings are located on a site with light soil.
To prevent your celery from getting sick, pay due attention to such basic prevention as:
- Disinfection of planting material. The causative agents of many diseases of this culture are transmitted with seeds, so before sowing, they need to be soaked in water heated to + 48-49 degrees. The seeds are kept in water for 20 minutes, then two to three minutes are cooled in cool water and dried to a state of flowability.
- Compliance with culture – before and after celery, you can not grow umbrella family crops. Place the plantings in ventilated areas provided with good drainage.
- Removing plant debris from the beds immediately after harvesting and regular weed control in the nearest beds. Let me remind you that pathogens from grass easily migrate to cultivated plants.
- Pre planting soil dressing in phosphorus and potash fertilizers, as well as autumn liming of acidic soils.
- Periodic – once every two weeks – foliar top dressing of celery with a 0.04% solution of borax. To do this, 0.4 milligrams of the substance is added to 10 liters of water. For accurate dosage, it is convenient to use a two-milliliter syringe.
- Free placement of plants in the garden – thickened planting is one of the main reasons for the rapid development of powdery mildew.