Tomatopotato late blight in the home garden this article describes tomatopotato late blight, including symptoms. F are required for the late blight organism, phytophthora infestans, to infect a potato plant. Late blight occurs commonly in coastal environments and in the southern san joaquin valley in california. Early blight is a common foliage disease of potato and tomato. Today, it is still the greatest threat to the potato yield. The terms early and late refer to the relative time of their appearance in the field, although both diseases can occur at the same time. Late blight of potato is identified by blackishbrown lesions on leaves and stems figures 3,4 that may be small at first and appear watersoaked or have chlorotic borders but expand rapidly and the entire leaf becomes become necrotic. 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.
Yes, it is possible to get rid of late blight disease on tomato and potato plants using proven, organic and natural methods. Early blight and late blight of potato ct integrated pest. Late blight phytophthora infestans fungus is in the same genus as the fungus causing pink rot p. Because the disease can move very easily from one garden. 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. These plants are all members of the solanaceae or nightshade family. Late blight of potato is a serious disease caused by phytophthora infestans. Early blight of potato is caused by the fungus, alternaria solani, which can cause disease in potato, tomato. 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. In the early to mid1990s, a late blight epidemic struck experimental potato plantings at kunia, oahu, causing widespread crop loss in a matter of days s. It has historical significance as the cause of the irish potato.
Late blight of potato, caused by the water mold phytophthora infestans, has the potential to be a very destructive disease of potato in michigan. Late blight of tomato and potato is a potentially destructive fungal disease in maryland home gardens. Most potato varieties have no or only weak defence against phytophthora. Early blight biology and control in potatoes figure 1. Early blight lesions first appear as small, irregular to circular darkbrown spots on lower leaves. Be aware of the relative susceptibility to late blight of the potato varieties that you are planting. Early blight lesions are characterized by an alternating series of light tan and darkcolored concentric. Late blight lb, caused by the oomycete phytophthora infestans mont. 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. It affects both potato foliage in the field and tuber in the storage which can absolutely destroy a crop, producing a 100% crop loss.
Early blight of potato with diagram plant diseases. Late blight in potato andy robinson, assistant professor and potato extension agronomist, ndsuuniversity of minnesota gary secor, professor, plant pathology department, ndsu neil gudmestad, university distinguished professor, plant pathology department, ndsu late blight is caused by the funguslike oomycete pathogen phytophthora infestans. Late blight is the most destructive of all potato disease and responsible for the irish famine in the middle of the 19 century. Late blight, caused by the oomycete phytophthora infestans, continues to be the main biotic constraint of potato produc tion. Potato late blight is one of the most infamous diseases in agriculture. The pathogen is highly variable and adapt to the newly bred varieties and fungicides. 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. Late blight of tomato potato university of maryland extension. Under humid conditions, white mold may appear on the underside of the leaf around. Late blight of potato, caused by a funguslike organism, is a constant threat wherever. Late blight is caused by phytophthora infestans, a funguslike organism. Late blight of potato caused by phytophthora infestans pi oomycete was the cause of the irish potato famine in 1840 cause loses of up to 2. Late blight of potato and tomato phytophthora infestans mont.
It is estimated that the yearly economic losses, through. The pathogen can survive between growing seasons as mycelium in potato tubers and plant tissues, and on alternative hosts of solanaceae family. Late blight of potatoes is caused by the pathogen phytophthora infestans. Late blight is not as likely to occur in warmer, more arid regions of the state. The disease develops rapidly once spores infect leaves and late blight takes hold, eventually killing the whole plant. About the late blight pathogen late blight is caused by phytophthora infestans, a pathogen. Potato late blight and pest management is a challenge, particularly in developing countries, and ipmlb is a knowledge intensive technology, that requires farmers to manage many concepts related to pathogens and pests, the host, the environment, and the management options. Wharton, phil nolte and nora olsen late blight was reported in potatoes on august 20, 20 in central bingham county in a field with solid set irrigation. When this occurs, fall is the time for gardeners to. Pdf late blight of potato phytophthora infestans i. Phytophthora infestans an overview sciencedirect topics. Late blight of potato, page 1 of 4 late blight disease caused by phytophthora infestans devastates potato foliage and tubers. Late blight of potato phytophthora infestans symptoms.
Severity values determination late blight forecasting starts with. As infected potato tubers cause the primary sources of. The use of area under the disease progress curve to assess resistance to late blight in potato germplasm. Effects of poligenic resistance and techniques of timing fungicide applications. When late blight has been a problem in your area during the growing season, you should not save potatoes to replant. 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. If late blight is not controlled in the field,pre and postharvest yields can be lost completely. May 2017 late blight in potato andy robinson, assistant professor and potato extension agronomist, ndsuuniversity of minnesota gary secor, professor, plant pathology department, ndsu neil gudmestad, university distinguished professor, plant pathology department, ndsu late blight is caused by the funguslike. In this article we will discuss about the late blight of potato caused by fungi. Key 10 recommendations to minimize late blight in potato fields. Phytophthora infestans, the causal agent of potato late blight, triggered the devastating great irish famine that lasted from 1845 to 1852.
Biology of late blight free moisture on the foliage and an air temperature of 45. Forecasting potato late blight in western nebraska. These disappointing losses are the result of late blight, a disease caused by the fungus phytophthora infestans. Symptoms green, brown or black watersoaked spots are seen on leaves and stems.
Potato or tomato plants that are infected may rot within two weeks. In other california potato growing areas its occurrence is sporadic, depending on the presence of the pathogen and cool, damp weather conditions. Late blight is caused by the funguslike oomycete pathogen phytophthora infestans. It is of common occurrence both in cold as well as in warm regions in india and abroad where, potatoes and tomatoes are grown. Found on tomato and potato plants, late blight is caused by the fungus phytophthora infestans and is common throughout the united states. Nov 20, 2018 this publication is available in a pdf file format. Late blight of potato and tomato oregon state university. Forecasting is the better option for management of late blight, if accurately forecasted and promptly information reaches to the end users.
Learning to control potato late blight a facilitators guide presentation late blight, caused by phytophthora infestans mont. The disease is slowed down by a return to hot, dry weather. The disease occurs in humid regions with temperatures ranging between 4 and 29 c 40 and 80 f. On several occasions the disease has reached disastrous proportions.
Late blight, is a disease that strikes tomatoes and potatoes. The crop has experienced enormous growth in terms of production throughout the world in recent decades because of. This potentially devastating disease can infect potato foliage and tubers at any stage of crop development. Under hotter and drier conditions, the lesions turn brown, dry out, and appear papery. Potato late blight update 81920 and late season recommendations phillip s. 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. 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.
Late blight affects the foliage, fruits, and tubers of potato and tomato. Late blight of potatoes is the same late blight that affects tomatoesit will spread from one to the other. The current recommendation is not to store potatoes if more than 5% late blight or other tuber rots are present. Chapter 9 fungal, oomycete, and plasmodiophorid diseases. Late blight was a major culprit in the 1840s european, the 1845 irish, and the 1846 highland potato famines. The most sustainable strategy to manage tomato late blight lb would be to deploy an integrated system including cultural practices, fungicide application, and the use of cultivars with broadspectrum genetic resistance against lb. Development of late blight resistant potato for africa. It was first reported in the 1830s in europe and in the us.
Biological control of potato late blight using isolates of. The late blight pathogen, phytophthora infestans, is an important and destructive pathogen on potato and tomato. 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. 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.
Lucas, in advances in food security and sustainability, 2017. Tomato transplants in home gardens may also be a source of late blight. True to its name, the disease occurs later in the growing season with symptoms. Under relative humidity in excess of 80%, lesions may appear purple to black with white sporangial growth. Early blight, caused by alternaria solani, is also often called potato blight. Organic seed potatoes, fingerlings, onion sets, shallots, and garlic p. This is the same disease that caused the irish potato famine in the 1840s. Early blight and late blight of potato ct integrated. Potato late blight, caused by phytophthora infestans is a most destructive plant pathogen and can lead to serious economic losses in potato. This guide began with an experience in ecuador where late blight is particularly severe in highland potato production. Late blight, also called potato blight, disease of potato and tomato plants that is caused by the water mold phytophthora infestans. Eliminate potato cull piles and all other sources of living tubers and eliminate volunteer potatoes from last season.
Late blight was responsible for the irish potato famine in the midnineteenth century daly, 1996. Late in the season it is advisable to avoid excessive irrigation as tubers become infected with late blight when spores wash down through the soil from infected leaves. This disease can affect tomatoes and potatoes in commercial fields, backyard gardens, greenhouses, and high tunnels and. This is the least common blight on tomato plants, but, by far, it is the most destructive. An investigation was carried out at potato research station sialkot during 201415 and 201516 crop season to find out suitable fungicides to combat the late blight disease of potato. According to mathur, singh and nagarkote 1971, there have been outbreaks of early blight of potato during the. Late blight can also infect potato tubers causing a rapid tuber rot.
The potato gene rb, cloned from the wild potato species solanum bulbocastanum, confers partial resistance to late blight, caused by the oomycete pathogen phytophthora infestans. Late blight occurs commonly in coastal environments and in the southern san joaquin. Late blight does not affect humans or the flavor of the potatoes. 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. Ethylicin prevents potato late blight by disrupting. Late blight can occur at any time during the growing season when the weather is cool and wet. Some strains of the trichoderma genus can act as potential biocontrol agents and are able to control many plant disease in crops. Miller research llc late blight caused by phytophthora infestans has occurred sporadically in idaho since 1995. Here are some tips for recognizing late blight, understanding and controlling its. Late blight, which thrives on live plant material of the solanaceae family potato, tomato, eggplant, pepper, and nightshade, can become firmly established very quickly, destroying a crop in just 3 to 5 days.
Fungicides for managing late blight in potato updated july 3, 2018 jeff miller, terry miller, and trent taysom. Primarily a disease of potatoes and tomatoes, late blight may affect other members. It is vital that gardeners understand late blight isnt like any other tomato and potato diseases. Pdf management of late blight of potato semantic scholar. Abstract this chapter discusses the major potato diseases worldwide. Late blight is a notorious disease that is often associated with the irish potato famine, yet even today it remains a destructive disease. Fungicides for managing late blight in potato updated july 3. This is the first report of late blight in idaho for several years. Tomato potato late blight in the home garden this article describes tomato potato late blight, including symptoms.
Under the right conditions see avoid conditions that favor late blight, p. Estimating foliage late blight severity in the field. Late blight of irish potato phytophthora infestans composite of early lesions on leaves and further development of larger, dark brown patches as foliage withers. Late blight on potato and tomato 2 weather conditions. 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. 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 msubred cultivar, jacqueline lee yellowflesh table stock, and cultivar defender lightly russeted long type are highly resistant to the us8 genotype of late blight and are currently being used as. Pdf late blight disease of potato and its management.
Late blight is a serious fungal disease of potatoes. The disease spreads most readily during periods of warm and humid weather with rain. Pdf effectiveness of different fungicides against late. Organic potato production is a flourishing sector of the british columbia food industry and acreage dedicated to that crop is increasing. Late blight of potato phytophthora infestans biology. It causes fruit rot and plant death on tomatoes and potatoes. This chapter summarizes the current understanding of phytophthora infestans. 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.
It can infect and destroy the leaves, stems, fruits, and tubers of potato and tomato plants. In order to better characterize this partial resistance phenotype, we have compared host resistance responses mediated by rb with those mediated by the s. Late blight of potato with diagram biology discussion. Resistant cultivars no potato cultivars are immune to late blight, and most cultivars planted in michigan are susceptible. It also has historical significance as the cause of the irish potato famine during the 1840s. It affects potato, tomato and, occasionally, eggplant and other members of the potato family. Learning to control potato late blight a facilitators guide. Diagnostic or baseline studies conducted in bangladesh. Late blight was widespread in many fields in southern idaho in 2015 but was not reported in 2016 or 2017. Late blight caused by phytophthora infestans is one of the most dreaded diseases of potato worldwide and cause significant loss in production.