Potato Blight Potato Encystment of the Fungus and Could Lead to Earlier Earlier to Lead Could and Fungus the Of
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D D N N A Potato Blight SCIENCE A TECHNOLOGY N I I ACTION FOURTHSECOND EDITIONEDITION D D N N A Potato Blight SCIENCE A TECHNOLOGY N I I ACTION FOURTHSECOND EDITIONEDITION No one knows exactly when or how potatoes first arrived in Life Cycle Methods of Control Ireland. Some claim they were brought by Sir Francis Drake Under normal conditions P. To effectively control the disease we need to have some knowledge of or by Sir Walter Raleigh, both of whom visited Ireland on their infestans reproduces asexually the life cycle of the parasite and the conditions that affect its growth. The return voyages from South America. Historical records refer (vegetatively) by means of following are some of the methods used to control the disease: lemon-shaped, thin-walled, to potatoes being grown in Co. Down in 1606 and to a toll sporangia (21-38 × 12-23 μm) 1. Avoid planting infected tubers since the disease can over-winter in (tax)No onone potatoes knows as exactlyearly as 1623when in Youghal,or how Co.potatoes Cork. By first arrivedthat are borne in on theLife tip of aCycle the tubers. Methods of Control the middle of the seventeenth century one can find many sporangiophore branch. The Ireland. Some claim they were brought by Sir Francis Drake Under normal conditions P. 2. Good earthing up around the potatoTo plants effectively during thecontrol growing the disease we need to have some knowledge of sporangiophore can be references to the potato as a source of food for the Irish. This Fig. 1 Sporangia and sporangiophore season helps to prevent infection of the tubers. or by Sir Walter Raleigh, both of whom visited Irelandidentified on their by periodicinfestans swellings reproduces asexually the life cycle of the parasite and the conditions that affect its growth. The would suggest, that even at that time, the potato was (reproduced with permission from return voyages from South America. Historical recordsalong refer its length where(vegetatively) the byTomVolkFungi.net) means of 3. Spraying the leaves on a regular basisfollowing with specific are fungicidessome of theto methods used to control the disease: extensively grown in Ireland. This is still the case today. sporangia were produced.lemon-shaped, thin-walled, Teagasc is a state organisation that provides research, advisory to potatoes being grown in Co. Down in 1606 and to a toll protect the foliage from infection, see below. These sporangia cansporangia be spread to(21-38 healthy × plants 12-23 by μm)wind, rain and 1. Avoid planting infected tubersand since training the servicesdisease for can the over-winteragriculture and in food industry in Classification(tax) on potatoes as early as 1623 in Youghal, Co. Cork.insects, Bywhere they germinate directly or indirectly leading to further 4. Spores present on the leaves at the time ofthe harvest tubers. can be a serious Ireland. Over 1,500 staff work at over a hundred locations spread of the disease.that are borne on the tip of a source of tuber infection. Therefore the foliage should be burned off The Irish potato crop occupies an area of 20,000 ha and was worth in throughout the country. They work with all sectors of the the middle of the seventeenth century one can find many sporangiophore branch. The at least 3 weeks before harvest. This can be done by spraying with a excess of €140m in 2007. There are many different varieties of potato, Sporangia can germinate directly by means of a germ tube or indirectly 2. Good earthing up around theagriculture potato andplants food duringindustries the and growing with rural development sporangiophore can be corrosive solution such as sulfuric acid. includingreferences Golden toWonder, the potato Kerr’s Pink, as aRecord, source Cara of and food Rooster. for the Irish.by means This of motile zoospores. Indirect germination is favoured byFig. short 1 Sporangia and sporangiophore season helps to prevent infectionagencies. of the Teagasc tubers. employs over 200 scientists and 300 identified by periodic swellings Roosterwould has suggest,been the most thatsuccessful even variety at on that the Irish time, market. the It is potatoperiods was of exposure to temperatures below 100C while direct germination (reproduced5. Plant with resistant permission varieties from of potato. technicians in research, and many other specialist staff in training very acceptable for boiling, steaming, mashing, roasting, baking, is favoured by higheralong temperatures. its length Germination where isthe followed by TomVolkFungi.net) 3. Spraying the leaves on a regularand advisory basis roles.with specific fungicides to The use of blight resistant varieties is more sustainable, more economical chippingextensively and crisping. grown in Ireland. This is still the case today.attachment to the hostsporangia plant (encystment were). Penetration produced. of the leaf surface Teagasc is a state organisation that provides research, advisory is by means of an and more environmentally acceptable. protect the foliage from infection,Teagasc see isbelow firmly. focused on the challenges facing the tillage Potatoes are grown by planting tubers in the soil. Shoots grow up above These sporangia can infectionbe spread peg and to thishealthy plants by wind, rain and sector and rural communities. One of the organisation’s objectivesand training services for the agriculture and food industry in the ground from the tubers, eventually producing leaves and flowers. Classification insects, where they germinateis followed directlyby the or indirectlyFungicides leading to further 4. Spores present on the leaves atis theto increase time of theharvest competitiveness can be a seriousof tillage crops such Ireland.as Over 1,500 staff work at over a hundred locations This vegetatively propagated crop is subject to attack by viruses, spread of the disease.growth of hyphae source of tuber infection. Thereforepotatoes, the and foliage to ensure should the quality be burnedand safety off of the produce and The main varieties of potato grown in Ireland are susceptible to infection throughout the country. They work with all sectors of the bacteria,The Irish and potato fungi. Ofcrop these, occupies late blight, an areacaused of by20,000 the fungus, ha and was worth in between the cells. the protection of the rural environment. with late blight, especially in the leaves. Withat leastmost potato3 weeks varieties, before harvest. This can be done by spraying with a Phytophthoraexcess of infestans €140m (Mont.) in 2007. de Bary, There is the are most many important. different varieties of potato, Sporangia can germinateFinally directly the cells by meansare of a germ tube or indirectly agriculture and food industries and with rural development disease control can only be achieved by the routine application of including Golden Wonder, Kerr’s Pink, Record, Cara and Rooster. by means of motile zoospores.penetrated Indirectby means germination is favoured by short corrosive solution such as sulfuricPotato acid. research is conducted at the Crops Research Centre,agencies. in Teagasc employs over 200 scientists and 300 This lesson will focus on late blight – its structure, significance, of a haustorium. The fungicides throughout the growing season. The chemicals used for Carlow and current projects are in the areas of potato breeding classification,Rooster has life beencycle andthe prevention. most successful variety on the Irish market. It is periods of exposure to temperatures below 100Cblight while control direct fall germination into three different groups: protectant, translaminar haustorium enables 5. Plant resistant varieties of potato.and late blight control. The latter is focused on the interactiontechnicians of in research, and many other specialist staff in training is favoured by higher temperatures. Germinationand systemic is fungicides.followed Theby annual cost of late blight control is in very acceptable for boiling, steaming, mashing, roasting, baking, the fungus to gain the host, the pathogen and the environment with special referenceand advisory roles. excess of €8m. Thechipping Search and crisping.for the Cause of attachment to the hostnourishment plant (encystment from the ). Penetration of the leaf surface The use of blight resistant varietiesto is fungicidemore sustainable, efficacy and more genetic economical variation in the pathogen. leaf cells. Invasion of Protectantis by fungicidesmeans areof thean most widelyand used.more They environmentally rely on the acceptable.Teagasc also has technical advisors who work closely with theTeagasc is firmly focused on the challenges facing the tillage LatePotatoes Blight are grownDisease by planting tubers in the soil. Shoots grow up above the leaf is rapid, completeinfection coverage peg of and the foliagethis with the chemical, but have little effect potato industry, particularly in the area of disease control and thesector and rural communities. One of the organisation’s objectives In thethe mid-nineteenthground from centurythe tubers, late blight eventually disease wasproducing a major cause leaves of and flowers. eventually resulting in on the tubers. Translaminar fungicides move across the surface of the is followed by the industry’s obligations under environmental and health and safety famine here in Ireland, the effect of which lasted a hundred years. Fig. 2 Phytophtora life cycle death of the leaf leaf but will not move from one leaf to another. is to increase the competitiveness of tillage crops such as Fungicides legislation. AlthoughThis vegetatively potato blight is unlikelypropagated