Diseases

1.1. A "Golden Age" for Fungi: High Humidity and Microclimate

Most carrot diseases, especially those affecting the leaves, are fungal in nature. Their development generally requires two conditions: the presence of free moisture on the leaves and a certain temperature. Dense carrot tops create their own microclimate within the bed—humid and poorly ventilated. This is an ideal environment for spore dispersal and the development of infections such as alternaria blight (brown leaf spot) or powdery mildew (Swiader & Ware, 1992; Akhatov et al., 2013). That is why in rainy years or with frequent overhead watering, the risk of epiphytotics increases sharply.

1.2. Constant Contact with Soil: An Infection Source Close to the "Target"

The root is constantly in the soil, which is a natural reservoir for a huge number of microorganisms. Many of them are saprophytes, but some, such as fungi of the genera Fusarium, Pythium, or bacteria, are pathogens lying in wait for weakened or damaged plants (Autko et al., 2012). Particularly dangerous are the agents of storage diseases, which live in the soil for years and do not lose their virulence. When the carrot begins to swell, its skin becomes denser, but microcracks, wounds from pests, or simply excessive soil moisture open the gates for infection to penetrate deep into the root while still in the field (Welbaum, 2015).

1.3. Mechanical Injury: The "Entry Ticket" for Infection

The carrot root consists of juicy, sugar-rich tissue that is ideally suited for feeding many pathogens. Any damage—whether a bite from a carrot fly larva, a crack from uneven watering, or a scratch during weeding—becomes an "entry point" for disease. This problem is especially relevant during harvesting and storage. The many wounds that roots sustain during mechanical harvesting make them vulnerable to fungi and bacteria that begin to develop actively in the storage (Swiader & Ware, 1992). That is why careful harvesting and preparation for storage are critically important steps, not just an aesthetic issue.

In a nutshell:

Problems with carrot diseases are rooted in its biology. We cannot change the fact that the root grows in the ground, but we can and must manage moisture, protect the plant from injury, and carry out timely prevention. Understanding these three factors is the first step toward a healthy harvest. In the following chapters, we will break down how to distinguish one disease from another and what to do in each specific case.

Great, let’s continue. We now move on to the most noticeable group of diseases—those that affect the tops. It is often through the leaves that we first notice something is wrong, and the condition of the tops directly determines whether the root will fill out.

2.1. Alternaria Blight (Brown Leaf Spot)

Pathogen: fungi Alternaria dauci and Alternaria radicina (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. This is perhaps the most common and dangerous foliar disease. The first signs can be seen on older, lower leaves: small brownish or black spots appear, often with a yellowish border (chlorotic halo). Over time, the spots enlarge, coalesce, and the leaf blade curls, turns brown, and dries up as if scorched (Swiader & Ware, 1992; Geoffriau & Simon, 2021). Elongated dark streaks are visible on the petioles. In humid weather, a grayish or dark olive coating—fungal spores—forms on the spots.

Why it occurs. The fungus thrives in warm (+20…+28 °C) and humid conditions, so disease outbreaks often occur in rainy summers or with frequent overhead irrigation (Autko et al., 2012). Spores are carried by wind, water, and insects. The pathogen overwinters on plant debris and seeds, so unremoved tops are the main source of infection for the next season (Geoffriau & Simon, 2021).

What to do.

• Prevention. Crop rotation (return carrots to the same site no sooner than after 3–4 years). Thoroughly destroy all plant debris in autumn. Use varieties and hybrids with relative resistance (e.g., 'Bolero', 'Maestro', 'Sirocco') (Autko et al., 2012; Akhatov et al., 2013).
• Treatment. At the first signs, treat the plantings with approved fungicides (e.g., 'Skor' or 'Quadris') strictly according to the instructions. For amateur gardeners, biological products based on hay bacillus (Bacillus subtilis) are also available, working as prevention and at early stages (Geoffriau & Simon, 2021).

2.2. Cercospora Leaf Spot (Cercosporosis)

Pathogen: fungus Cercospora carotae (Akhatov et al., 2013).

How it manifests. Symptoms are very similar to alternaria blight, but there are nuances. Spots in cercosporosis are usually more rounded with a distinct center—lighter in the middle and dark brown at the edges. Spots often appear along the margins of leaf lobes, causing the leaf to curl. In humid weather, a light gray coating, rather than olive, is noticeable on the spots (Akhatov et al., 2013). The fungus also affects petioles, causing elongated cankers.

Why it occurs. Disease development is favored by warm (+23…+28 °C) and humid weather. The source of infection is plant debris and seeds. Unlike alternaria, cercosporosis often appears later in the season, although under favorable conditions it can attack earlier (Swiader & Ware, 1992).

What to do. Control measures are the same as for alternaria: crop rotation, removal of tops, use of resistant hybrids. Specific chemical products against cercosporosis on carrots are usually not singled out—the same broad-spectrum fungicides (e.g., 'Skor', 'Quadris') are effective against it as well (Akhatov et al., 2013).

2.3. Bacterial Blight (Bacteriosis)

Pathogen: bacterium Xanthomonas hortorum pv. carotae (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. This bacterial disease can initially be confused with fungal leaf spots, but it has characteristic features. Small yellowish spots appear on leaves and petioles, quickly darkening to brown or almost black, with an oily (water-soaked) margin and a yellow halo. On affected petioles, droplets of sticky exudate—bacterial slime—often appear (Geoffriau & Simon, 2021). In dry weather, the affected areas dry out and crack. With severe development, leaves die, and bacteria can penetrate the root, causing rot in the field (Akhatov et al., 2013).

Why it occurs. Bacteria are spread by raindrops, irrigation water, wind, and insects. Warm, humid weather favors the disease. The infection is seed-borne and persists in plant debris (Autko et al., 2012).

What to do.

• Prevention. The main thing is to use healthy seeds (preferably treated). Observe crop rotation, avoid mechanical damage to plants—bacteria enter most easily through wounds. Remove weeds from the Apiaceae family (wild carrot, hogweed), as they can be reservoirs of infection (Akhatov et al., 2013).
• Treatment. Chemical control of bacteria in the field is difficult. During the growing season, copper‑containing products (e.g., Bordeaux mixture) may help, but they do not always guarantee complete cure. Preventive measures are most effective. Affected plants should be removed and burned.

2.4. Powdery Mildew

Pathogen: fungi Erysiphe heraclei and Leveillula taurica (in southern regions) (Geoffriau & Simon, 2021; Akhatov et al., 2013).

How it manifests. This disease is unmistakable. A white, powdery coating appears on the upper side of leaves (less often on the lower side), first as isolated rounded spots, then as a continuous layer. The coating is easily rubbed off with a finger. Over time, it becomes denser, turns grayish, and small black dots—fungal fruiting bodies (cleistothecia)—become visible on it. Affected leaves turn yellow, dry out, and crumble (Swiader & Ware, 1992).

Why it occurs. Unlike other fungal diseases, powdery mildew prefers not very humid weather, but rather warm and dry conditions with frequent temperature fluctuations. However, spore germination requires high air humidity. The disease often appears in the second half of summer. The source of infection is plant debris and weeds from the Apiaceae family (Autko et al., 2012).

What to do.

• Prevention. Grow resistant hybrids (e.g., 'Bolero', 'Maestro', 'Sirocco'). Maintain spatial isolation from other Apiaceae crops. Avoid dense sowings to allow better aeration of the tops.
• Treatment. At the first signs, treat plants with the fungicide 'Skor' (which also works against powdery mildew) or, for amateur farms, spray with an infusion of manure or a solution of baking soda with soap (this gives a temporary effect). In Europe, the product 'Prosaro' is also used, but it is not yet registered for all crops in Russia (Akhatov et al., 2013).

Important Note: Viral Diseases of Tops

To round off the topic, let us mention viruses. On leaves, they often cause mosaic (alternation of light and dark areas), vein yellowing, curling, and stunting. The best known are carrot mosaic virus (Carrot mosaic), carrot thin leaf virus, and aster yellows caused by a phytoplasma (Aster yellows) (Geoffriau & Simon, 2021; Akhatov et al., 2013). Viruses are transmitted by aphids, leafhoppers, and other sucking insects.

The main problem: a virus‑infected plant cannot be cured. The only protection is prevention: control of insect vectors, removal of affected plants, and destruction of reservoir weeds. Viruses are usually not seed‑borne (except for some), but can persist in mother roots (Akhatov et al., 2013).

In a nutshell:

Foliar diseases are mostly fungal (alternaria, cercosporosis, powdery mildew) or bacterial (blight). All favor humidity but respond differently to temperature. The main control measures are crop rotation, removal of plant debris, use of resistant varieties, and timely fungicide treatments (for fungal) or removal of diseased plants (for bacterial and viral). In the next chapter, we will cover diseases that hide in the soil and affect the root itself.

Great, let's move on to the most important topic for gardeners—diseases that affect the root while still in the ground. After all, it is the harvest we want to preserve.

3.1. Black Rot (Alternaria Root Rot)

Pathogen: fungus Alternaria radicina (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. This is one of the most insidious diseases. In the field, only small, dark, slightly sunken spots may be seen on the root, often at the crown (where the petioles attach) or on the shoulders. The spots may feel dry (Akhatov et al., 2013; Swiader & Ware, 1992). The main danger is that the fungus thrives during storage: spots enlarge, turn black, penetrate deeper, and the root rots, covered with a dark coating. On seedlings, the same fungus causes "damping‑off" — a constriction at the base of the stem and death of young plants (Akhatov et al., 2013).

Why it occurs. The fungus lives in soil, on plant debris, and in seeds. In soil, it can survive up to 8 years (Akhatov et al., 2013)! Disease development in the field is favored by warm (+20…+25 °C) and humid weather. Roots with mechanical damage are especially susceptible—wounds make it easier for the fungus to enter.

What to do.

• Prevention. Crop rotation with return to the same site no sooner than after 3–4 years. Carefully select seeds—only from healthy plants or treated. Destroy all plant debris. Apply balanced fertilizers: excess nitrogen increases susceptibility to the disease (Akhatov et al., 2013; Autko et al., 2012).
• Treatment. During the growing season, at the first signs of alternaria on leaves, use fungicides ('Skor', 'Quadris'). For amateur gardens, the biological product 'Fitosporin‑M' has proven effective; it can be sprayed on plants and applied to the soil. However, completely eliminating A. radicina from the soil is difficult, so emphasis should be on prevention (Geoffriau & Simon, 2021).

3.2. Cavity Spot (Pythiosis)

Pathogen: a group of oomycete fungi of the genus Pythium (P. violae, P. sulcatum, P. ultimum, and others) (Geoffriau & Simon, 2021; Akhatov et al., 2013).

How it manifests. A very characteristic symptom: small (1–10 mm), oval, sunken spots‑lesions appear on the root, arranged across the root (Geoffriau & Simon, 2021). The spots may be translucent or black, often cracking at the edges. The root may appear almost healthy, but secondary infections enter the lesions, and rot starts during storage. With severe infection, roots become misshapen, branched, and lose marketable quality (Akhatov et al., 2013).

Why it occurs. Fungi of the genus Pythium live in the soil and infect roots starting from the seedling stage. Different species require different conditions: some are active in warm weather (above +18 °C), others in cool (+10…+18 °C) and humid conditions (Geoffriau & Simon, 2021). Acidic soil, excess nitrogen fertilizers, dense sowings, and poor crop rotation favor the disease (Akhatov et al., 2013). The infection is soil‑borne and persists on plant debris.

What to do.

• Prevention. Grow resistant hybrids (e.g., 'Bolero', 'Maestro', 'Sirocco', 'Tempo') (Autko et al., 2012; Geoffriau & Simon, 2021). Practice crop rotation. Lime acidic soils. Avoid waterlogging. Importantly, apply well‑rotted manure or compost, not fresh, as fresh manure promotes pythium development (Akhatov et al., 2013).
• Treatment. Chemical control in the field is difficult. In some cases (mainly in seed production), soil disinfection is carried out. Gardeners should focus on agronomic practices. Studies show that reducing planting density and regulating soil moisture (drainage, ridge planting) help reduce disease symptoms (Geoffriau & Simon, 2021).

3.3. White Rot (Sclerotinia Rot)

Pathogen: fungus Sclerotinia sclerotiorum (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. In the field, this disease is less common than in storage, but it can start in the bed, especially if the summer is wet and cool. At the infection site (often at the crown or on the side), the tissue softens, becomes wet, watery, but does not change color or becomes slightly brown. Later, a white, cottony mycelial growth appears on the surface, on which black, hard sclerotia (up to 1–2 cm in size) then form—these are the "resting" organs of the fungus that can wait in soil for years (Akhatov et al., 2013; Geoffriau & Simon, 2021).

Why it occurs. The fungus is a polyphage, attacking over 400 plant species. It persists in soil as sclerotia. Infection occurs through wounds on roots or through weakened, frost‑damaged, or overripe roots. Excess nitrogen, dense planting, and high humidity favor the disease (Autko et al., 2012).

What to do.

• Prevention. Crop rotation with return of carrots after 3–4 years. Avoid preceding crops highly susceptible to white rot (tomatoes, cucumbers, cabbage). Thoroughly remove plant debris. Lime acidic soils. Do not over‑fertilize with nitrogen (Akhatov et al., 2013).
• Treatment. Chemical treatments in the field are of low efficacy. The main control is carried out in storage (we will discuss this in the next chapter). In gardens and dachas, it is important to remove infected plants promptly and not store even roots with a suspicion of disease.

3.4. Bacterial Soft Rot (Bacterial Wet Rot)

Pathogen: bacteria Pectobacterium carotovorum subsp. carotovorum and others (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. This disease can start both in the field and in storage. In soil, it mostly affects weakened or injured roots. The tissue becomes soft, watery, slimy, and disintegrates into a mash with a characteristic unpleasant odor. The root softens completely, although the skin may remain intact for a while (Geoffriau & Simon, 2021; Swiader & Ware, 1992). On leaves and petioles, the bacterium can also cause watery dark spots and wilting (Akhatov et al., 2013).

Why it occurs. Bacteria live in soil and on plant debris. They are wound pathogens—they enter only through mechanical damage, cracks, insect bites (especially carrot fly larvae and wireworms). Warm (+22…+29 °C) and humid weather favors disease development (Akhatov et al., 2013).

What to do.

• Prevention. The main thing is to avoid injuring roots. Careful weeding, control of soil‑dwelling pests. Avoid waterlogging. Practice crop rotation. Do not water heavily before harvest. Select only absolutely healthy, undamaged roots for storage (Swiader & Ware, 1992).
• Treatment. Copper‑containing products at early stages may somewhat restrain spread, but there is no effective treatment in the field. Diseased plants should be immediately removed and burned.

3.5. Fusarium Dry Rot

Pathogen: fungi of the genus Fusarium (mainly F. solani, F. avenaceum, F. culmorum) (Geoffriau & Simon, 2021; Akhatov et al., 2013).

How it manifests. On roots growing in the soil, the disease can appear in various ways. Sometimes it is sunken, dark, dry spots on the surface that deepen over time and may crack. Often, infection starts at the root crown, where black rot appears at the junction with petioles. With severe infection, the root becomes shriveled, light, and woody (Akhatov et al., 2013). On young plants, Fusarium causes wilting: lower leaves turn yellow and dry, the plant is stunted, and necroses appear on the roots (Geoffriau & Simon, 2021).

Why it occurs. The fungi are widespread in soil and on plant debris. They enter the root through wounds or through intact cells at the root collar. Warm autumn (+18…+23 °C), mechanical damage during harvesting, and plant weakening due to lack of moisture or nutrients favor disease development (Akhatov et al., 2013). In storage, Fusarium progresses, causing dry rot.

What to do. Measures are the same as for other root rots: crop rotation, removal of plant debris, use of healthy planting material, careful harvesting. Varieties with high resistance to Fusarium are not yet widespread, but some hybrids ('Canterbury', 'Soprano') show relative tolerance (Autko et al., 2012; Geoffriau & Simon, 2021). Among biological products, 'Fitosporin' and Trichoderma (soil antagonistic fungi) can be used for prevention.

In a nutshell:

Root diseases in the soil are mostly the result of a combination of three factors: the presence of the pathogen in the soil, root injury, and favorable conditions (moisture, temperature). We have no universal cure for all, but there is a reliable prevention system: crop rotation + healthy seed material + careful agronomic practices + pest control. Remember: many diseases start in the field but fully manifest during storage. Therefore, attention to roots in the field is the key to their long life in the cellar. In the next chapter, we will cover what diseases await the crop after harvest.

4.1. Black Rot (Alternaria) in Storage

Pathogen: fungus Alternaria radicina (Akhatov et al., 2013; Geoffriau & Simon, 2021).

How it manifests. If in the soil black rot often goes unnoticed, in storage it shows itself in full force. On roots, most often at the top (crown) or at mechanical injury sites, dry, sunken, black spots appear. They gradually enlarge, may cover a significant part of the surface, and penetrate deep inside, even to the core (Geoffriau & Simon, 2021). Unlike wet rots, the affected tissue remains relatively firm and dry. On the surface of the rot, a grayish or olive‑black sporulation coating is often visible. With severe infection, the root shrivels, becomes light, and is unfit for consumption (Akhatov et al., 2013; Swiader & Ware, 1992).

Why it occurs. The source of infection is contaminated soil, plant debris, and, importantly, seeds (Autko et al., 2012). The fungus A. radicina is very persistent and can survive in soil for up to 8 years (Geoffriau & Simon, 2021). In storage, elevated temperature and air humidity provoke disease development. Most often, roots with micro‑injuries from harvesting, or those harvested in wet weather, are affected. Also at high risk are carrots harvested under‑ripe or over‑ripe (Akhatov et al., 2013).

How to prevent it.

• Selection. This is the main rule! Before storing, carefully inspect every carrot. Discard any specimens with the slightest dark spots, cracks, scratches, as well as wilted, frost‑damaged, or misshapen ones. Even one diseased root can infect its neighbors (Swiader & Ware, 1992).
• Proper harvesting. Try to harvest carrots in dry weather. Do not knock off soil by striking roots against each other—this injures the skin. If carrots were dug from wet soil, they should be dried in a well‑ventilated place (not in the sun!) until surface moisture is completely gone (Autko et al., 2012).
• Storage conditions. The ideal temperature for storing carrots is 0…+2 °C, with relative humidity of 90–95% (Swiader & Ware, 1992). Sharp fluctuations in temperature and humidity are unacceptable—they cause condensation and provoke diseases. The storage should be clean and pre‑disinfected (whitewashing with lime and copper sulfate).
• Biological protection. Before storage, roots can be treated with biological products, e.g., 'Fitosporin‑M' (according to instructions), which suppresses fungal infection (Akhatov et al., 2013). Dusting with chalk (creating an alkaline environment unfavorable to fungi) also helps.

4.2. White Rot (Sclerotinia) in Storage

Pathogen: fungus Sclerotinia sclerotiorum (Geoffriau & Simon, 2021; Akhatov et al., 2013).

How it manifests. This is perhaps the most dangerous and rapidly spreading storage disease. It starts with a small area on the root surface that becomes soft, wet, and watery, but does not darken—it retains its natural color or becomes slightly brown. Very quickly, this area is covered with a lush, white, cottony mycelial growth. The mycelium easily spreads to neighboring roots, gluing them into a rotting clump (Geoffriau & Simon, 2021). After some time, black, hard, irregularly shaped structures—sclerotia, resembling bits of soil—appear on the white coating. The fungus literally sucks all the juices from the root, turning it into a soft, watery mass with an unpleasant odor (Akhatov et al., 2013; Swiader & Ware, 1992).

Why it occurs. The causal fungus is a notorious polyphage. Sclerotia (its "resting" organs) can survive for years in soil, plant debris, and even in the storage itself (Geoffriau & Simon, 2021). In storage, the disease develops in foci. The most common causes are:

• Storing roots that are chilled or frost‑damaged.
• Harvesting under‑ripe or over‑ripe carrots.
• Excess nitrogen fertilizers during the growing season (tissues become loose).
• Root damage (entry points for infection).
• Too high a temperature in the storage (optimum for the fungus is +15…+20 °C, but it can grow even at +1 °C) (Akhatov et al., 2013).

How to prevent it. All the same as for black rot, but with additional emphasis:

• Selection. White rot especially quickly "eats" frost‑damaged and wilted roots. Mercilessly exclude them.
• Storage regime. Temperature and humidity are critical. Aim for +1 °C to slow fungal development.
• Reduce foci. If you notice one diseased root, immediately remove it along with 2–3 nearest neighbors, because the mycelium may already have spread to them (Geoffriau & Simon, 2021). Dust the infected spot in the storage with quicklime or chalk.
• Field prevention. Practice crop rotation, do not apply fresh manure, use balanced fertilizers (Autko et al., 2012). Interestingly, planting bio‑fumigant cover crops (e.g., white mustard) in the off‑season helps reduce the number of sclerotia in the soil (Geoffriau & Simon, 2021).

4.3. Fusarium Dry Rot

Pathogen: fungi of the genus Fusarium (mainly F. solani, F. avenaceum, F. culmorum) (Geoffriau & Simon, 2021; Akhatov et al., 2013).

How it manifests. In storage, Fusarium manifests as dry rot. Dark, slightly sunken spots appear on roots, which gradually dry out and become shriveled. The affected tissue becomes brownish or brown, becomes crumbly, and easily crumbles (Swiader & Ware, 1992). On the surface of the spots, a whitish‑pink or white‑green sporulation coating may be visible (Geoffriau & Simon, 2021). Unlike black rot, infection often starts not at the crown but on the sides or at the tip. The rot develops slowly but steadily, and the root eventually dries out completely, turning into a mummy (Akhatov et al., 2013).

Why it occurs. Fusarium fungi are widespread in soil and plant debris. They often infect weakened plants already in the field, causing wilting and root necrosis (Autko et al., 2012). In storage, the disease is activated at elevated temperatures (especially if the harvest was stored in warm autumn weather, +18…+23 °C). Like other rots, Fusarium favors mechanically injured roots—wounds make it easiest for the fungus to enter (Akhatov et al., 2013).

How to prevent it.

• Selection and drying. As with all rots, the main thing is to select only absolutely healthy roots and dry them well before storage.
• Storage conditions. Low temperature (0…+2 °C) is the best protection against Fusarium. Fungi of the genus Fusarium are sensitive to low temperatures, though they can develop at +4 °C (Geoffriau & Simon, 2021).
• Field agronomy. Crop rotation, no fresh manure, moderate watering, and pest control reduce field infection. Some hybrids, such as 'Bolero' and 'Maestro', show relative resistance to Fusarium (Autko et al., 2012; Geoffriau & Simon, 2021).

Practical Tip: How to Store Carrots to Reduce Rot

For gardeners and small farmers, the following time‑tested methods are especially popular:

1. Storage in boxes with sand. The sand should be slightly moist (not wet!). It creates a stable microclimate, protecting roots from drying out and from rot spread.

2. Storage in plastic bags. Carrots are filled into bags and left open (not tied) for air access. In bags, a naturally high humidity is created, which is good for carrots. The main thing is to avoid condensation and overheating.

3. Treatment with "chalk slurry". Before storage, roots are dipped in a chalk solution (or dusted with dry chalk). Chalk creates an alkaline surface environment that inhibits the development of many fungi (Swiader & Ware, 1992).

4. Ventilation. The storage should be regularly ventilated (if outside temperature is not too low) to prevent accumulation of ethylene and other gases that stimulate rotting.

In a nutshell:

The main enemies of carrots in storage are black, white, and Fusarium rots. All of them usually enter the storage from the field as microspores or latent infections. Three main rules for saving the harvest: 1) careful selection of healthy, undamaged roots; 2) creation of optimal conditions (0…+2 °C, 90–95% humidity); 3) preventive treatments (biological products, chalk, sand). Remember: disease is easier to prevent than to cure. In the next, concluding chapter, we will answer the most practical question: when can diseased carrots be salvaged and when should they be ruthlessly discarded.

5.1. Why Is Timely Culling Important?

Carrots are often consumed fresh (salads, juices) or with minimal heat treatment. Therefore, safety comes first. Many pathogenic fungi (particularly Fusarium, Alternaria, Sclerotinia) can produce mycotoxins—poisonous substances dangerous to humans and animals (Geoffriau & Simon, 2021; Akhatov et al., 2013). Some toxins are heat‑stable and do not break down during boiling or stewing. Moreover, even the visibly healthy part of a root that was next to rot may already be permeated with mycelium and contain toxins (Swiader & Ware, 1992). Therefore, the rule "cut off the rotten part and it's safe to eat" is not always safe for carrots.

The second reason is economic: one rotting root releases moisture and spores that stimulate disease development in neighbors. In storage, where humidity is high and space is tight, infection spreads very quickly. Therefore, timely culling is the main method of protecting the entire crop (Autko et al., 2012).

5.2. Signs That Require Immediate Removal and Discarding of the Root

These signs indicate deep tissue damage, high risk of toxins, and infection of neighboring roots.

5.3. When the Root Can Still Be Salvaged (with Safety Precautions)

In some cases, if the damage is superficial and fresh, you may use part of the root, but with great caution.

5.4. Practical Action Plans When Rot Is Detected in Storage

1. Immediate inspection. If you notice at least one diseased root, immediately check the entire box or bag. Rot may be hidden in the center, so go through everything, inspecting every root.

2. Zoning. Remove not only the obviously diseased root but also all roots that were in contact with it (within a radius of 5–10 cm). They may be infected, but symptoms have not yet appeared.

3. Sanitary treatment of the area. The place where the diseased root lay (box, shelf, sand) must be disinfected. Use a solution of potassium permanganate, copper sulfate, or simply dust with slaked lime (Autko et al., 2012).

4. Disposal. Diseased roots must not be put into the compost pile (especially if there are sclerotia or mycelium)—this will spread infection throughout the area. It is best to burn them or remove them from the site (Akhatov et al., 2013).

5.5. Summary Table for Decision‑Making

In a nutshell:

Safety comes first. If you have the slightest doubt about the quality of a root, it is better to discard it. Your harvested crop is your labor, but health is more valuable. Use simple criteria: if rot is deeper than 3 mm, has affected the core, an unpleasant odor or mold appeared—such a root must never be kept or consumed. For surface damage, you may try to salvage part, but only with obligatory heat treatment and immediate consumption. And most importantly—do not let one diseased carrot spoil your entire harvest: regularly check your stored stock and promptly remove sources of infection.