What is blight in tomatoes?
233043#1
Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this symptom are called blights. Several notable examples are:
Blight
9940234#43
Various forms of mildew and blight are common tomato afflictions, which is why tomato cultivars are often marked with a combination of letters that refer to specific disease resistance. The most common letters are: LB – "late blight", V – "verticillium" wilt, F – "fusarium" wilt strain I, FF – "fusarium" wilt strain I and II, N – "nematodes", T – "tobacco mosaic virus", and A – "alternaria".
Tomato
11459992#0
Alternaria solani is a fungal pathogen, that produces a disease in tomato and potato plants called early blight. The pathogen produces distinctive "bullseye" patterned leaf spots and can also cause stem lesions and fruit rot on tomato and tuber blight on potato. Despite the name "early," foliar symptoms usually occur on older leaves. If uncontrolled, early blight can cause significant yield reductions. Primary methods of controlling this disease include preventing long periods of wetness on leaf surfaces and applying fungicides.
Alternaria solani
165450#0
Phytophthora infestans is an oomycete or water mold, a microorganism that causes the serious potato and tomato disease known as late blight or potato blight. (Early blight, caused by "Alternaria solani", is also often called "potato blight".) Late blight was a major culprit in the 1840s European, the 1845 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C. Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C.
Phytophthora infestans
44567553#1
Buckeye rot of tomato affects tomato plants, although there are many other plants that are affected, including pepper, potato, tobacco, pineapple, and various other hosts. Upon infection, brown and greyish-green water soaked spots appear on the fruit. These spots develop into lesions that resemble the markings of a bull's eye with alternating dark and light brown concentric rings. These are very smooth lesions, barely raised, unlike the rough lesions found in late blight "(Phytophthora infestans)", which is a similar pathogen. Finally, a white fungal-like growth may appear within the lesion. While fruit rot is the most common symptom, damping off and stem cankers are possible. The disease does not affect the foliage of the plant, which further helps separate it from late blight .
Buckeye rot of tomato
11128630#0
Stemphylium solani is a plant pathogen fungus in the phylum Ascomycota. It is the causal pathogen for grey leaf spot in tomatoes and leaf blight in alliums and cotton, though a wide range of additional species can serve as hosts. Symptoms include white spots on leaves and stems that progress to sunken red or purple lesions and finally leaf necrosis. "S. solani" reproduces and spreads through the formation of conidia on conidiophores. The teleomorph name of "Stemphyllium" is Pleospora though there are no naturally known occurrences of sexual reproduction. Resistant varieties of tomato and cotton are common, though the pathogen remains an important disease in Chinese garlic cultivation.
Stemphylium solani
10812281#3
AAL’s main symptom is cankers in the stem. It resides in seeds and seedlings, and is often spread by spores as they become airborne and land on plants. It can also spread throughout other plants. Under severe infection, lesions enlarge and become coalesced causing blighting of the leaves. This symptom progression occurred in research done in Pakistan: the symptoms on affected tomatoes started with yellowing and browning of the lower leaves, then began developing on the leaf tips and along the margins of the leaf petiole. This progression continued until the entire leaves were covered in diseased tissue and then fell off. In addition under to necrotic leaves and petioles, plants are found to have severe defoliation, with considerable yield losses when it occurs before flowering. The tomato fruit can also be infected as well, with brown cankers dotting them and making them inedible. Once the disease has spread to a certain point, little can be done to save the tomato plant.
Alternaria alternata
11459992#12
Early blight caused by "A. solani" is the most destructive disease of tomatoes in the tropical and subtropical regions. Each 1% increase in intensity can reduce yield by 1.36%, and complete crop failure can occur when the disease is most severe. Yield losses of up to 79% have been reported in the U.S., of which 20-40% is due to seedling losses (i.e., collar rot) in the field.
Alternaria solani
165450#14
Potato and tomato varieties vary in their susceptibility to blight. Most early varieties are very vulnerable; they should be planted early so that the crop matures before blight starts (usually in July in the Northern Hemisphere). Many old crop varieties, such as King Edward potato are also very susceptible but are grown because they are wanted commercially. Maincrop varieties which are very slow to develop blight include Cara, Stirling, Teena, Torridon, Remarka, and Romano. Some so-called resistant varieties can resist some strains of blight and not others, so their performance may vary depending on which are around. These crops have had polygenic resistance bred into them, and are known as "field resistant". New varieties such as Sarpo Mira and Sarpo Axona show great resistance to blight even in areas of heavy infestation. Defender is an American cultivar whose parentage includes Ranger Russet and Polish potatoes resistant to late blight. It is a long white-skinned cultivar with both foliar and tuber resistance to late blight. Defender was released in 2004.
Phytophthora infestans
11128630#1
"Stemphylium solani" is of greatest concern in tomatoes, potatoes, peppers, garlic, onions, and cotton, though a wide range of over 20 species have proven susceptible. In tomatoes and potatoes, the resulting disease is known as grey leaf spot. In alliums it is known as leaf blight. Additional hosts are listed below.In alliums, infection is first visible as oval white spots, 1–3 mm in length, scattered irregularly over the leaf surface. These spots grow into red or purple colored lesions with a yellow margin and finally progress to leaf wilting and necrosis. Experimentally infected plants have been shown to progress from initial infection to leaf necrosis within eight days. Infection is found only on the stems and leaves of plants. In tomatoes, "S. solani" symptoms begin as round to oval dark specks on both sides of the leaf with older leaves being affected first. Young lesions may have a yellow halo. As lesions age, they become gray, dry and brittle, eventually falling away to create shot-holing in the leaf. Severe infection results in leaf drop.
Stemphylium solani
35158708#2
BABA was first found to increase the resistance of plants to disease in 1960, when it was observed that it decreased late blight of tomato. Further tests were made in the 1960s, but it was not until the 1990s that interest in the compound was renewed. Since then, it has been shown to be effective in many different pathosystems under controlled conditions. Both perennial and annual plants have been shown to respond, as well as both monocot and dicot plants in the Solanaceae, Cucurbitaceae, Compositae, Fabaceae, Brassicaceae, Graminae, Malvaceae, Rosaceae, and Vitaceae families. Pathogen groups that have shown a response include viruses, bacteria, nematodes, fungi and oomycetes. It has also been shown to be effective in the field at protecting potato and tomato plants from late blight, grape vines from "Plasmopara viticola" and melons from "Monosporascus cannonballus".
Beta-Aminobutyric acid