Late blight is a devastating disease that has historical significance for its association with the irish potato famine of the 1840s. The disease is spread by windborne spores and by water splash. Late blight is a funguslike disease that mainly affects tomatoes and potatoes. Late blight is a potentially devastating disease of tomato and potato, infecting leaves, stems and fruits of tomato plants. A long wet period is required for sporulation but it can also occur under conditions of alternating wet and dry periods. Lesions generally appear quickly under warm, moist conditions on older foliage and are usually visible within 57 days after infection. These plants are all members of the solanaceae or nightshade family. Late blight remains the single most important potato disease, costing the industry an estimated. F are required for the late blight organism, phytophthora infestans, to infect a potato plant. The pathogen is highly variable and adapt to the newly bred varieties and fungicides. 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.
Phytophthora infestans an overview sciencedirect topics. The causal pathogen of late blight from potatoes was first described in 1845 by montagne and from tomato in 1847 by payen in france. Late blight affects the foliage, fruits, and tubers of potato and tomato. Spores are washed into the soil where they can infect tubers. Early blight and late blight of potato ct integrated pest. Pdf a model for early detection of potato late blight. Late blight of potatoes is caused by the pathogen phytophthora infestans. Potato late blight is one of the most infamous diseases in agriculture. It also has historical significance as the cause of the irish potato famine during the 1840s. Late blight can occur at any time during the growing season when the weather is cool and wet.
Of these, the most frequently reported is phytophthora infestans. About the late blight pathogen late blight is caused by phytophthora infestans, a pathogen. A disease of potatoes caused by the fungus phytophthora infestans. In other california potato growing areas its occurrence is sporadic, depending on the presence of the pathogen and cool, damp weather conditions. The disease is slowed down by a return to hot, dry weather. This guide began with an experience in ecuador where late blight is particularly severe in. Late blight is the disease that caused the irish potato famine of the 1840s figure 1.
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. This potentially devastating disease can infect potato foliage and tubers at any stage of crop development. The late blight organism produces three different spore. Late blight of potato and tomato oregon state university. Late blight was responsible for the irish potato famine in the midnineteenth century daly, 1996. If you cut across the surface of these infected areas, youll see a reddishbrown, dry, granular rot that extends up to half an inch into the flesh. Once late blight takes hold, the pathogen, phytophthora infestans, spreads rapidly and great distances. Estimating foliage late blight severity in the field. Here are some tips for recognizing late blight, understanding and controlling its.
This plant pathogen is one of the most notorious and devastating organisms in recent human history, being responsible for the terrible irish potato solanum. The white growth on the leaf underside see arrows, image below contains hundreds of spores of the pathogen that could be dispersed by wind to other leaves in this field or beyond. Lucas, in advances in food security and sustainability, 2017. The late blight pathogen, phytophthora infestans, is an important and destructive pathogen on potato and tomato. Impact late blight of potato is a devastating disease and a major threat to potato production. Field assessment of resistance in potato to phytophthora. Late blight of potato with diagram biology discussion. Research journal of ag potato late blight control with. The disease occurs in humid regions with temperatures ranging between 4 and 29 c 40 and 80 f.
Severity is used to graph disease progress curves and to calculate epidemic descriptors, such as the area under the disease progress curve audpc and the apparent infection rate r see summarizing the epidemic. Deepali tewari pandey, gbpuat this disease is caused by a fungus called phytopthora infestans. Today, it is still the greatest threat to the potato yield. It is famous for being the cause of the 1840s irish potato famine, when a million people starved and a million and a half people emigrated. Wilt, tuber rots, and seedpiece decay 22 jellyend rot 24 late blight 25 leak 27 phoma tuber rot 28 pink rot 28 powdery mildew 28 rhizoctonia canker black scurf 29 scab, common 30. Potato or tomato plants that are infected may rot within two weeks. It has historical significance as the cause of the irish potato. Late blight of potato was responsible for the irish potato famine of the late 1840s. Late blight is caused by the funguslike oomycete pathogen phytophthora infestans. Late blight of tomato and potato is a potentially destructive fungal disease in maryland home gardens. Late blight on potato and tomato 2 weather conditions.
Phytophthora infestans, the causal agent of potato late blight, triggered the devastating great irish famine that lasted from 1845 to 1852. These were the main symptom seen in a commercial field on li in 2009 when this disease was first found. Late blight of tomato potato university of maryland extension. Late blight was a major culprit in the 1840s european, the 1845 irish, and the 1846 highland potato famines. A recent classifi cation scheme based on molecular analysis of the nuclear srrna gene as well as ultrastructural data, places the genus phytophthora in the kingdom chromista together with golden and brown algae and diatoms.
When conditions are right such as the cold, wet weather and the thunder storms of 1993, late blight can survive very well and be moved as much as 50 miles in a day. Late blight is not only the most serious fungal disease of potatoes, it also occurs almost everywhere where potatoes are grown and is especially important in the traditional potato growing areas. However, it was 1863 before debary established beyond doubt that this organism, phytophthora infestans, was the cause of late blight. Early blight is principally a disease of aging plant tissue. Estimation of severity is crucial to study epidemics of potato late blight lb see estimation of disease severity. Symptoms green, brown or black watersoaked spots are seen on leaves and stems. Yes, it is possible to get rid of late blight disease on tomato and potato plants using proven, organic and natural methods.
This publication is available in a pdf file format. Potato late blight, caused by the oomycete pathogen phytophthora infestans, is the most notorious plant disease known, largely due to the epidemic that swept across europe in 184546, leading to famine and mass emigration in ireland fraser, 2003. Disease triangle the critical thing that you need to remember is that late blight needs living tissue to survive. In north america, late blight survives between seasons in infected seed tubers, cull piles and volunteer plants. The pathogen favors wet weather with moderate temperatures 60 to 80f, high humidity and frequent rainfall.
In addition, the disease spurred the emergence of the field of plant pathology. This is the same disease that caused the irish potato famine in the 1840s. If weather, such as heavy rain, favors late blight infection, apply at 5 to 7day intervals. 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. Late blight phytophthora infestans fungus is in the same genus as the fungus causing pink rot p. Under humid conditions, white mold may appear on the underside of the leaf around. Learning to control potato late blight a facilitators guide presentation late blight, caused by phytophthora infestans mont.
Late blight tomato disease late blight symptoms and treatment. Potato culture is very sensitive to the pathogen attack. Late blight is a serious fungal disease of potatoes. Under hotter and drier conditions, the lesions turn brown, dry out, and appear papery. Under relative humidity in excess of 80%, lesions may appear purple to black with white sporangial growth. Spread of late blight potatoes may be exposed to late blight during the growing season from inoculum produced on infected cull piles, volunteer potato plants, or plants developing from infected seed. In this article we will discuss about the late blight of potato caused by fungi. Ethylicin prevents potato late blight by disrupting. Review on major potato disease and their management in.
Under the right conditions see avoid conditions that favor late blight, p. This is a list of diseases and disorders found in potatoes. Generally, potato yield loss attributed primarily to late blight is dependent on variety susceptibility or tolerance resistant and disease management practices. In our country, potato late blight is frequent and dangerous in.
Pdf late blight disease of potato and its management. 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. Late blight, also called potato blight, disease of potato and tomato plants that is caused by the water mold phytophthora infestans. Learning to control potato late blight a facilitators guide.
Potato solanum tuberosumlate blight pacific northwest. 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. An increasing severity of late blight in many potato growing areas, a shift in pathogen population toward increased specific virulence and an increasing tolerance to the most effective late blight. Phytoplasma infection or anything that constricts the stem, including but not limited to rhizoctonia canker, heat necrosis, chemical injury, mechanical injury, wind injury. Phytophthora infestans, causal agent of late blight late blight of potato and tomato is caused by phytophthora infestans. Late blight can cause in favorable years a 4050% loss of the harvest if the control measures are not applied. Early blight, caused by alternaria solani, is also often called potato blight. Late blight continued to be a devastating problem until the 1880s when the first fungicide was discovered. When this occurs, fall is the time for gardeners to.
Large leaf spots lesions are common with late blight. Late blight occurs commonly in coastal environments and in the southern san joaquin valley in california. Found on tomato and potato plants, late blight is caused by the fungus phytophthora infestans and is common throughout the united states. Late blight occurs commonly in coastal environments and in the southern san joaquin. Potato plants are most at risk from late blight under cool and moist conditions.
Seed treatments can reduce the chance of spread of late blight from seed and prevent spread of late blight between seed pieces during cutting, treating, and handling operations. 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. It was the leading factor in the irish potato famine of the 1850s where millions of people starved because of the devastation wrought by this deadly disease. If weather, such as heavy rain, favors lateblight infection, apply at 5 to 7day intervals.
Phytophthora infestans, which spreads rapidly in the foliage of potatoes and tomatoes causing collapse and decay. It was first reported in the 1830s in europe and in the us. These disappointing losses are the result of late blight, a disease caused by the fungus phytophthora infestans. Late blight symptoms late blight a serious disease of.
Late blight tomato disease is the rarest of the blights that affect both tomatoes and potatoes, but it is also the most destructive. The disease spreads most readily during periods of warm and humid weather with rain. While there are many diseases that can affect your tomat o and potato plants that wont severely impact your harvest, late blight should be taken seriously. A model for early detection of potato late blight disease. Tomatopotato late blight in the home garden this article describes tomatopotato late blight, including symptoms. Is it safe to eat tomatoes infected with late blight. Late blight is caused by the funguslike comycete pathogen phytophthora infestans. Modified key to potato diseases and disorders 3 fungus diseases 20 botrytis gray mold 21 charcoal rot 21 early blight 21 fusarium. True to its name, the disease occurs later in the growing season with symptoms. Late blight can also infect potato tubers causing a rapid tuber rot. Understanding late blight organic seed potatoes, fingerlings. This disease can affect tomatoes and potatoes in commercial fields, backyard gardens, greenhouses, and high tunnels and can result in substantial losses of tomato and potato crops.
The disease spreads quickly in fields and can result in total crop failure if untreated. Infected potatoes have shallow, brownish or purplish lesions on the surface of the tuber. Potatoes with late blight are still considered to be a serious disease so its important for growers to learn about treating potato late blight in the garden. Lb has been identified as a major disease of tomato and potato and is one of the most devastating plant diseases of all time. Tomato transplants in home gardens may also be a source of late blight. Late blight management for fall, winter and spring occasionally, new england growers experience a widespread outbreak in tomatoes and potatoes of late blight, phytophthora infestans. Late blight caused by phytophthora infestans is one of the most dreaded diseases of potato worldwide and cause significant loss in production.