Early blight Tomato | Do You Know This Instant & Secret Method

early blight of tomato
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Tomatoes are believed to have been domesticated in pre-Columbian Mexico, from which they derive their name. The wild species presumably originated in Peru or Ecuador in the Andes Mountains of South America. Early in the 16th century, the Spanish appear to have been the first European nation to use the tomato as a food. This was particularly the case in Spain and Italy. Because it is linked to the poisonous belladonna and deadly nightshade, tomatoes were once cultivated as ornamental plants in France and northern Europe and considered with suspicion as a food source. The most common fungal disease of the orchids is early blight tomato. This disease damages the crops in the United States, Australia, India, China, Canada, the Philippines, and other countries where tomatoes grow.

Early blight of the tomato, the most destructive of these diseases, is a serious concern during the breeding phase. Alternaria solani-caused diseases can harm the leaves, stems, and fruits of tomato plants. Breeding for resistance to early blight tomato has been conducted for over 60 years; nevertheless, the quantitative expression and polygenic inheritance of the resistance have prevented the generation of cultivars with high levels of resistance. Several wild species accessions have been reported to have high levels of resistance to early blight; however, breeding lines still carry undesirable horticultural traits from the donor parent.

What is an Early Blight Tomato

early blight-infected tomatoes in a red tray
early blight tomato

The fungus Alternaria solani causes early blight tomatoes, which is one of the most prevalent tomato illnesses. It almost yearly causes substantial leaf, stem, and fruit damage to West Virginia’s tomato production. Early blight tomatoes can also damage the foliage of potatoes. Five to ten dark, round dots on a leaf indicate early blight tomato. The spots, which can be up to half an inch in diameter, feature a distinctive target-like pattern composed of concentric rings or ridges encircled by a golden halo. Spots can progressively coalesce to produce bigger lesions that can finally damage an entire leaf. Eventually, infected patches may migrate to the stem and fruit, where they manifest as dark, sunken spots. Cankers with a similar appearance, which are dark and depressed in the middle, are frequently observed on stems at or above the soil line.

Symptoms of Early Blight Tomato

Tomatoes and potatoes exhibit indications of early blight tomato on their stems, leaves, and tubers, respectively. Small black or brown lesions, often 1 to 2 mm in diameter, appear initially on leaves and, under ideal conditions, enlarge, frequently surrounded by a yellow halo. Lesions with a diameter greater than 10 mm display concentric rings of dark pigmentation. The “bullseye” lesion is a classic early blight tomato symptom. As lesions spread and new ones grow, entire leaves may become chlorotic and dehisce, resulting in severe defoliation. Stem lesions often have a depressed look, a lens shape with a bright center, and the ring pattern of a solo lesions. The “collar rot” phase of the disease weakens or kills early tomato seedlings by causing sores around the stem.

How Does Early Blight Disease Spread? 

The fungus that causes early blight tomato can overwinter on dead plants or be transmitted from year to year in contaminated seeds. When it rains or a sprinkler system is used, any fungal conidia spores that have survived in the soil or plant debris are splattered on the lower leaves. When a thin film of water is present on a leaf, conidia can germinate. Foliage that stays wet for another 5 to 10 hours, depending on temperature, allows germinating conidia to infect tissues. Infections flourish in conditions of high humidity and temperatures exceeding 75 degrees Fahrenheit.

What is the Early Blight Pathogen’s Biology? 

Early blight tomato is caused by the fungal pathogen Alternaria solani. This creature is a Deuteromycete as it has no reported sexual dimorphism. The pathogenic fungi of the genus Alternaria are responsible for a variety of severe illnesses. The fungus can be easily cultured in an artificial medium such as V8 juice, where it grows into a densely pigmented gray/black hairy colony. Mycelium is haploid and septate and whose color darkens over time. It has been demonstrated that fluorescent lighting promotes sporulation in culture. Conidiophores carrying asexual conidia are carried alone or in chains of two. It is typical for beaked conidia to contain nine to eleven transverse septae. Due to physical and pathogenic variability among isolates, claims of the presence of races among A. solani isolates have surfaced.

Early Blight Tomato Disease Cycle

Alternaria solani feeds on contaminated farm manure during the winter. Developing a dark, lysis-resistant mycelium can extend the soil’s lifespan by many years. Chlamydospores with thicker walls are extremely unusual. In temperate climates, volunteer tomato, potato, horsenettle, and nightshade plants can withstand the disease. Temperatures and humidity promote disease transmission. Conidia can germinate in as little as forty minutes at temperatures between 28 and 30 degrees Celsius in the presence of free moisture. The regrowth of desiccated germ tubes during wet and dry periods can result in an infection.

Germ tubes can reach the epidermis of a leaf either through the stomata or directly. Infection is transmitted through harvesting cuts on potato tubers. In addition, spores have better difficulty penetrating the bigger lenticels that grow on harvested tubers while they are still moist. The interval between infection and the manifestation of foliar symptoms is regulated by climatic circumstances, leaf age, and cultivar susceptibility, among other variables. Aged plant tissue is especially susceptible to early blight tomato infection. When temperatures and humidity are optimal, lesions occur on older foliage in as little as seven days.

A prolonged period of wet weather is optimum for sporulation, although it can also occur during times of alternating wet and dry circumstances. Conidiophores form during wet nights, then on the second wet night, after exposure to light and drying conditions, spores emerge. The spread of conidia and the disease itself is facilitated by wind, splashing rain, and overhead irrigation. Early blight tomato infectious cycles occur repeatedly. During this season, the illness can rapidly spread and destroy the crop.

Disease Management of Early Blight Tomato

Cultural Practice Control Method

Early blight losses on tomato and potato plants can be reduced to an economic level by the use of sound cultural practices. In-field sanitation reduces initial inoculum in following crops because the virus overwinters in crop debris. If you wish to prevent disease in your crop fields, you should remove any dead vines or fruit. Before planting a new crop, it is necessary to eliminate disease-carrying weeds and volunteer plants such as nightshade and horsenettle.

Rotating fields to a non-susceptible host crop and employing pathogen-free seed or transplants helps reduce soil inoculum. To effectively manage tuber infection, tubers must be harvested at the optimal period. Premature tubers that are infected and unpleasant are a prevalent concern. The risk of tuberculosis can be minimized by avoiding wet harvesting and handling. Keeping tubers in an environment with temperatures between 50 and 55 degrees Fahrenheit, high relative humidity, and ample air circulation will limit the danger of infection.

Strategically timed overhead watering should be used to reduce crop leaf moisture. If the forecast calls for cool, overcast weather or late evening, you should refrain from watering the plants. If there is good drainage and no natural obstructions to airflow over the crop, such as rows of trees, leaves will dry up faster. Soil fertility is vital for controlling early blight tomatoes. The condition is more prevalent in nitrogen-deficient plants, especially those with senescent or otherwise old leaves. Disease management measures alleviate both plant stress and early blight tomato.

Chemical Control of Early Blight Tomato

The use of fungicides having both preventative and curative properties against early blight in tomato crops has been authorized. The majority of early blight treatment options rely on inexpensive protective fungicides like mancozeb and chlorothalonil. Every seven to ten days, these fungicides must be reapplied in order to preserve new growth and counteract the effects of weathering, which removes the chemical from the leaf surface. As a result of their persistent efficacy and multi-site mode of action, they are advantageous as tank-mix partners or for use in rotation with other fungicides, as they reduce the possibility that pathogen populations would develop resistance. In addition, the ability of such medications to kill several targets considerably reduces the likelihood that resistant strains would develop. Consistent administration is required, and their relatively high rates of consumption are disadvantageous.

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