Late blight of potato with diagram biology discussion. Early blight of potato with diagram plant diseases. Found on tomato and potato plants, late blight is caused by the fungus phytophthora infestans and is common throughout the united states. The pathogen favors wet weather with moderate temperatures 60 to 80f, high humidity and frequent rainfall. Symptoms green, brown or black watersoaked spots are seen on leaves and stems. These strains can infect a plant more rapidly so limiting the curative effects of some. Early blight is principally a disease of aging plant tissue. Late blight lb caused by the oomycete phytophthora infestans, is a major disease of potato and tomato worldwide and can cause up to 100% yield losses. Late blight lb, caused by the oomycete phytophthora infestans mont. Understanding late blight of tomatoes extension service. Late blight was a major culprit in the 1840s european, the 1845 irish, and the 1846 highland potato famines.
Phytophthora in hindi late blight of potato youtube. The causal fungus fruiting on the underleaf surface. Potato or tomato plants that are infected may rot within two weeks. In this article we will discuss about the late blight of potato caused by fungi. Early blight can be caused by two different closely related fungi, alternaria tomatophila and alternaria solani. Late blight control late blight is a community issue and those in the growing community need to be part of the solution. Late blight is spread from infected transplants, volunteer potato or tomato plants.
Alternaria solani is a fungal pathogen that produces a disease in tomato and potato plants called early blight. This potentially devastating disease can infect potato foliage and tubers at any stage of crop. It can infect and destroy the leaves, stems, fruits, and. Late blight was responsible for the irish potato famine in the midnineteenth century daly, 1996. Home gardeners should be aware of late blight caused by phytophthora infestans a very destructive and very infectious disease that kills tomato and potato plants in gardens and on commercial farms across the u. Under conditions that are favorable to late blight, epidemics in tomatoes seem to be more rapid than in potatoes. Potato late blight is one of the most infamous diseases in agriculture. Late blight is the disease that caused the irish potato famine of the 1840s figure 1. Late blight of potato phytophthora infestans symptoms. Late blight of potato late blight, caused by the fungus phytophthora infestans is potentially the most destructive disease of potato. Pdf potato and tomato late blight caused by phytophthora. The cell biology of late blight disease sciencedirect. Alternaria solani is a deuteromycete with a polycyclic life cycle.
Late blight of tomato and potato university of connecticut. The cyc late blight on tomato stems and fruit from osu plant disease handbook, htt p. Look for spots and patches on the leaves which grow rapidly and produce a furry white growth on the underside. The disease spreads most readily during periods of warm and humid weather with rain. Pdf late blight disease of potato and its management. A, rolling of upper leaves of potato plant caused by rhizoctonia infection of roots and underground portion of stems. Late blight is the disease that was responsible for the irish potato famine.
A long wet period is required for sporulation but it can also occur under conditions of alternating wet and dry periods. Potato late blight is one of the most serious diseases of potatoes, caused by the fungus phytophthora infestans, and the disease that singlehandedly caused the irish potato famine of the 1840s. It has historical significance as the cause of the irish potato. In the late twentieth century, there have been major reoccurrences and concern around the world over this pathogen and its disease due to recent mutations fry and goodwin, 1997. It is critical that gardeners understand that late blight is not like other tomato and potato diseases. Late blight caused by phytophthora infestans is one of the most dreaded diseases of potato worldwide and cause significant loss in production. Dec, 2016 late blight of potato all potato growing areas of the world the disease was reported.
The asexual life cycle of potato late blight 5 sporulation sporangia dispersal 2 zoospore formation 1 sporangial germination 3 zoospore encystment 4. Gray or brown lesions surrounded by a light green chlorotic area are very characteristic of late blight. Late blight is favored by cool, wet weather and will cycle repeatedly if weather conditions. F are required for the late blight organism, phytophthora infestans, to infect a potato plant. Early blight, caused by alternaria solani, is also often called potato blight. It is of common occurrence both in cold as well as in warm regions in india and abroad where, potatoes and tomatoes are grown. Contact the local extension service for current information on fungicideresistant late blight genotypes. Phytophthora is a genus of plantdamaging oomycetes, whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. Here are some tips for recognizing late blight, understanding and controlling its life cycle, and managing an infection should it appear in your garden. For better disease management and the planning of a spray program, several methods of late blight forecasting have been developed, and are based on observation of temperature and humidity conditions. Despite the name early, foliar symptoms usually occur on older leaves. Late blight is a potentially devastating disease of tomato and potato, infecting leaves, stems and fruits of tomato plants. According to mathur, singh and nagarkote 1971, there have been outbreaks of early blight of potato during the past5 or 6 years in the plains of uttar.
Lesions generally appear quickly under warm, moist conditions on older foliage and are usually visible within 57 days after infection. Leaf and stem lesions are typical of potato late blight. Some sources of resistance have been identified in wild relatives of tomato, and efforts are being made to bring higher levels of resistance into cultivars that are desirable for the market. When outbreaks of this disease occur, entire crops can be lost. Late blight occurrence since 1974 has been during years with a higher than normal number of rainy days just prior to or during the growing season. Late blight caused by the oomycete phytophthora infestans is the most serious disease of potato crops worldwide. Late blight caused by the oomycete phytophthora infestans is the most serious disease of potato crops. If late blight is suspected, contact the msu extension at 4069945572 or the mda quarantine specialist. B, lower portion of potato plant infected with rhizoctonia, note the myce. Late blight of potato and tomato phytophthora infestans mont. Pdf late blight caused by phytophthora infestans is one of the most dreaded diseases of potato worldwide and cause significant loss in production. In addition, the disease spurred the emergence of the field of plant pathology. Under these conditions, a disease cycle takes only three days.
Potato late blight fact sheet1983 cornell university. 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. The disease occurs in humid regions with temperatures ranging between 4 and 29 c 40 and 80 f. This potentially devastating disease can infect potato foliage and tubers at any stage of crop development. The disease spreads quickly in fields and can result in total crop failure if untreated. Late blight can also infect potato tubers causing a rapid tuber rot. Late blight of potatoes and tomatoes, the disease that was responsible for the irish potato famine in the midnineteenth century, is caused by the funguslike oomycete pathogen phytophthora infestans. The lesions on foliage are very similar to and can be confused with those caused by early blight alternaria solani and late blight phytophthora infestans. To control potato late blight, growers need to take a multipronged approach. These disappointing losses are the result of late blight, a disease caused by the fungus phytophthora infestans. Late blight is caused by the funguslike comycete pathogen phytophthora infestans. Lesions that look like this are about one week old. Cip the international potato center, peru estimates that about 15% of the annual production of developing countries is lost to potato late blight each year. High levels of nitrogen, moderate potassium and low phosphorus in the soil can reduce susceptibility of infection by the pathogen.
Potato blight or late blight disease is caused by the funguslike organism phytophthora infestans, which spreads rapidly in the foliage of potatoes and tomatoes causing collapse and decay. Unfavorable conditions may delay or temporarily interrupt the disease cycle. Late blight of potato and tomato oregon state university. Potato blight diseases learn how to identify potato blight. The disease is often observed on stems and leaves but when inoculum levels are high, the disease can also be seen on tubers. How to prevent late blight tomato blight gardeners supply. The fungus survives the winter in infected, stored potatoes, or in infected tubers missed during harvest and remaining unfrozen overwinter. Interaction with the potato plant and inoculum sources abstract the oomycete, phytophthora infestans, is one of the most important plant pathogens worldwide.
Disease cycle click on any picture to see the enlarged image. Late blight of tomato and potato background late blight of tomato and potato is caused by the funguslike pathogen phytophthora infestans. Late blight, also called potato blight, disease of potato and tomato plants that is caused by the water mold phytophthora infestans. Tomatopotato late blight in the home garden this article describes tomatopotato late blight, including symptoms. Consequently, the tolerance for late blight is usually very low. Cultural control alone or chemical control alone will not provide adequate protection during late blight epidemics. The pathogen produces distinctive bullseye patterned leaf spots and can also cause stem lesions and fruit rot on tomato and tuber blight on potato. These plants are all members of the solanaceae or nightshade family. Late blight of potato all potato growing areas of the world the disease was reported. The fungus can be transmitted from infected tubers to.
Late blight spores germinate at humidity levels above 90 percent and temperatures between 50 and 78 f. Most reports of late blight are submitted through this website. Alternaria tomatophila is more virulent on tomato than a. Late blight, a disease that strikes tomatoes and potatoes, can quickly ruin an entire crop and infect other plants as well. Because the disease can move very easily from one garden.
Symptoms of late blight infections on tomato fruit is similar to other phytophthora diseases and dark brown, firm lesions figure 14 occur that may enlarge and destroy the entire tomato fruit. The fungus that causes late blight is wellknown for its role in the irish potato famine of the mid19th century, when it nearly destroyed the irish potato crop and caused widespread starvation. It explains the life cycle, the conditions that are conducive to disease development and the recent genetic development of the pathogen. Early blight is a common foliage disease of potato and tomato. This plant pathogen is one of the most notorious and devastating organisms in recent human history, being responsible for the terrible irish potato solanum. Infected stems may harbor the sporangia hot, dry weather, sporulation continuing during the return of wet weather. Montana has a large seed potato industry, this disease poses a massive threat to our state economy. The disease causes death of fol iage and stems and a rot of tuber s in both fie ld and. True to its name, the disease occurs later in the growing season with symptoms often not appearing until after blossom.
Understanding late blight organic seed potatoes, fingerlings. Late blight lesions on tomato fruit are often followed by soft rot and disintegration as described for potato tubers. The fungus can be transmitted from infected tubers to potato foliage. Late blight first appears on the lower, older leaves as watersoaked, graygreen spots. Late blight is a serious fungal disease of potatoes. Late blight affects the foliage, fruits, and tubers of potato and tomato. The late blight organism produces three different spore. Late blight of potato was responsible for the irish potato famine of the late 1840s. Late blight, caused by the oomycete phytophthora infestans, is a major global disease of potato and tomato. This fact sheet explains the basics about late blight tomato disease and practical ways. Thus, all incoming potato plants and seed potatoes, as well as tomato plants are regulated by the state of montana. Cell biology is teaching us much about the developmental stages associated with infection, especially the haustorium, which is a site of intimate interaction and molecular exchange between pathogen and host. Historically, it is best known as the cause of the irish potato famine of the 1840s, which resulted in the death or emigration of over 2 million people from ireland martin et al.
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