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Infected (Fig black. turns later and brown becomes gradually that a leaf of edge the at patch green light a is infection of sign One tubers. and stems leaves, attack can it destroyer’; infestans Phytophthora name The Symptoms a as known is hyphae of group A cytoplasm. the in nuclei many have called that structures thread-like of up made fungus is It Oomycetes. ‘true’ class a be to infestans considered longer no Although Structure and Classification 1860s. the in Bary de Anton scientist German by the unveiled eventually was fungus the of view cycle life full The unpopular afungus. by caused the was it that took others the while weather, the natural as to such due was causes it that maintained of group level one certain controversy; a to led scientific This cause. underlying the major a establish was to there search 1845 in disease the of outbreak initial the Following years. hundred loss. a economic significant cause lasted still can it which of today, effects effect devastating to have such is unlikely blight potato the Although Ireland, in of here cause major a famine was disease blight late century mid-nineteenth the In Disease Blight Late significance, The Search for Cause the of structure, its – blight late on prevention. and cycle life focus classification, will lesson This infestans Phytophthora fungus, the by caused blight, late these, Of fungi. and bacteria, This flowers. and leaves producing eventually tubers, the from ground the tubers planting by grown are Potatoes baking, roasting, mashing, steaming, boiling, andchipping crisping. Rooster. for is and It acceptable market. Irish Cara the very on variety Record, successful most Pink, the been has Kerr’s Rooster Wonder, Golden potato, of varieties including different many are in There 2007. worth in was €140m and of ha excess 20,000 of area an occupies crop potato Irish The Classification was potato the time, that at today. case the still is This Ireland. in grown even extensively that suggest, This would Irish. the for food of source many a as find potato the to can one references century seventeenth the of middle the By Cork. Co. Youghal, in 1623 as early as toll potatoes a on to (tax) and 1606 in Down Co. in grown being potatoes to refer records Historical their on America. 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Infected (Fig black. turns later and brown becomes gradually that a leaf of edge the at patch green light a is infection of sign One tubers. and stems leaves, attack can it destroyer’; infestans Phytophthora name The Symptoms a as known is hyphae of group A cytoplasm. the in nuclei many have called that structures thread-like of up made fungus is It Oomycetes. ‘true’ class a be to infestans considered longer no Although Structure and Classification 1860s. the in Bary de Anton scientist German by the unveiled eventually was fungus the of view cycle life full The unpopular afungus. by caused the was it that took others the while weather, the natural as to such due was causes it that maintained of group level one certain controversy; a to led scientific This cause. underlying the major a establish was to there search 1845 in disease the of outbreak initial the Following years. hundred loss. a economic significant cause lasted still can it which of today, effects effect devastating to have such is unlikely blight potato the Although Ireland, in of here cause major a famine was disease blight late century mid-nineteenth the In Disease Blight Late significance, The Search for Cause the of structure, its – blight late on prevention. and cycle life focus classification, will lesson This infestans Phytophthora fungus, the by caused blight, late these, Of fungi. and bacteria, This flowers. and leaves producing eventually tubers, the from ground the tubers planting by grown are Potatoes baking, roasting, mashing, steaming, boiling, andchipping crisping. Rooster. for is and It acceptable market. Irish Cara the very on variety Record, successful most Pink, the been has Kerr’s Rooster Wonder, Golden potato, of varieties including different many are in There 2007. worth in was €140m and of ha excess 20,000 of area an occupies crop potato Irish The Classification

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. Phytophthora Phytophthora protectant, translaminar hyphae hyphae fungicides outbreaks of the disease in any year. a form of would method new such as and years 10 over for soil the in survive also can greater in result could which pathogen the in variation genetic produce will oospore Sexual an of production the in resulting Ireland. an of in reproduction follows fertilisation rare extremely is this though sexually, reproduce also can fungus The Reproduction Sexual P. of infestans cycle life the follow to below diagram the Use infection. initial initial the following the another to crop one from and of crops within air-borne days rapidly 4-5 multi-cycle, within This sporangia of infection. crop fresh a with stomata the through emerge sporangiophores the conditions, favourable Under by followed is Germination temperatures. higher ( plant host the to attachment by favoured is of periods below to exposure 100C while temperatures germination direct by short favoured is germination Indirect zoospores. motile of by means indirectly or tube agerm of means by directly germinate can Sporangia disease. the of spread where they insects, orleading germinate directly indirectly to further and rain wind, by plants healthy to spread be can sporangia These sporangia were produced. the where length its along swellings periodic by identified sporangiophore can be sporangiophore a of tip the on borne are that thin-walled, of sporangia means lemon-shaped, by (vegetatively) infestans Under normal conditions P. Cycle Life Phytophtora life cycle 2Phytophtora Fig. oogonium to to . Sexual reproduction reproduces

2-8 1-3 μm) 12-23 × (21-38 virulence by an an by branch. The The branch. over-wintering from the making of the initial cross until the new variety can be be can variety new the until cross initial years. fifteen the about takes grown commercially of making variety the potato new a from multiplying and testing breeding, of process The is process of type This breeding. propagated. selective as known vegetatively are they fungus the found, to are resistance good show that plants potato When blight. to resistance for tested are they while the All underground. tubers produce and grow hybrids The (hybrids). parents both of combination genetic a are grow that plants potato new The out. planted seedlings the and sown then are produced are that seeds The cross. initial the as known is This variety). other of the part on it female to the dusting and variety one from , aggressiveness or or aggressiveness , antheridium asexually legislation. safety and health and environmental under obligations industry’s the and pathogen. control disease of area the in the the with particularly industry, potato closely in work who variation advisors technical genetic has also and Teagasc efficacy fungicide to the host, the reference and with special pathogen the environment of interaction the on focused is latter The control. blight breeding late and potato of areas the in are projects in current and Centre, Carlow Research Crops the at conducted is research Potato as such crops environment. rural the of protection the tillage of and produce the of safety and quality competitiveness the ensure to and potatoes, the increase to is tillage the facing challenges One and sector of rural communities. the objectives the organisation’s on focused firmly is Teagasc 300 and scientists roles. advisory and 200 training in development staff over specialist other many and rural research, in technicians employs with Teagasc and industries agencies. locations food hundred and a agriculture over at the of work sectors all with in work They country. the throughout staff industry food 1,500 and Over agriculture Ireland. the for services training and Teagasc www.teagasc.ie and the many scientific projects they are involved in at there work who people Teagasc, the about out Find encystment of the fungus and could lead to earlier earlier to lead could and fungus the of

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. AN D SECOND EDITIONFOURTH 4. 5. and more environmentally acceptable. environmentally more and The use of is varieties blight resistant more more economical sustainable, 1. disease: the control to used methods the of some are following the of cycle life the of knowledge some have to need we disease the control Toeffectively Methods of Control 2. 3. the tubers. However the fungus can become resistant to the the to resistant become can fungus the However fungicides. tubers. the including plant whole the affect metalaxyl, as such fungicides, Systemic another. to leaf one from move not will the but of leaf surface the across move fungicides Translaminar tubers. the on effect little have but chemical, the with foliage of the coverage complete the on rely They used. widely most the are fungicides Protectant €8m. of excess and disease control can only be achieved by the routine application of of groups: different three application into fall control blight routine the by achieved varieties, be throughout thefungicides growing used for season. The chemicals potato only most can With leaves. control the disease in especially blight, late with to infection are susceptible in grown of Ireland potato varieties The main Fungicides potato and allowing them to sexually reproduce (i.e. taking the pollen pollen the taking (i.e. of reproduce sexually to them varieties allowing and potato different two taking involves variety resistant a Developing Rooster. and Cara are varieties resistant these of Some of of the degrees Carlow, resistance. most with successful varying Co. Park, Oak in Centre Research Crop Teagasc the at developed been be to have likely of potato varieties 33 less some years the Over are by fungus. the they attacked grown are varieties resistant If blight. late by attack to susceptible not are that ones are potato of varieties Resistant Developing Resistant Varieties of Potato to resistance of level the years recent declined. has crops Irish in In metalaxyl 2007. to 1981 period the 0 from has varied to fungus 83% over of resistant The with number crops 1981. since out carried been has resistance metalaxyl of distribution in the confirmed of monitoring first aresult As crop. 1980 was the from taken samples metalaxyl fungicide the to resistance Ireland In Fungicide Resistance

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from the making of the initial cross until the new variety can be be can variety new the until cross initial years. fifteen the about takes grown commercially of making variety the potato new a from multiplying and testing breeding, of process The is process of type This breeding. propagated. selective as known vegetatively are they fungus the found, to are resistance good show that plants potato When blight. to resistance for tested are they while the All underground. tubers produce and grow hybrids The (hybrids). parents both of combination genetic a are grow that plants potato new The out. planted seedlings the and sown then are produced are that seeds The cross. initial the as known is This variety). other of the part on it female to the dusting and variety one from legislation. safety and health and environmental under obligations industry’s the and pathogen. control disease of area the in the the with particularly industry, potato closely in work who variation advisors technical genetic has also and Teagasc efficacy fungicide to the host, the reference and with special pathogen the environment of interaction the on focused is latter The control. blight breeding late and potato of areas the in are projects in current and Centre, Carlow Research Crops the at conducted is research Potato as such crops environment. rural the of protection the tillage of and produce the of safety and quality competitiveness the ensure to and potatoes, the increase to is tillage the facing challenges One and sector of rural communities. the objectives the organisation’s on focused firmly is Teagasc 300 and scientists roles. advisory and 200 training in development staff over specialist other many and rural research, in technicians employs with Teagasc and industries agencies. locations food hundred and a agriculture over at the of work sectors all with in work They country. the throughout staff industry food 1,500 and Over agriculture Ireland. the for services training and Teagasc www.teagasc.ie and the many scientific projects they are involved in at there work who people Teagasc, the about out Find is a state organisation that provides research, advisory advisory research, provides that organisation state a is SCIENCE TECHNOL SCIENCE TECHNOL ACTION IN ACTION

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mycelium and bi-flagellate and mycelium was potato the time, that at today. case the still is This Ireland. in grown even extensively that suggest, This would Irish. the for food of source many a as find potato the to can one references century seventeenth the of middle the By Cork. Co. Youghal, in 1623 as early as toll potatoes a on to (tax) and 1606 in Down Co. in grown being potatoes to refer records Historical their on America. South from Ireland voyages return visited whom of both Raleigh, Walter Sir by or Drake Francis Sir by brought were they claim Some Ireland. in arrived first potatoes how or when exactly knows one No and later turns black. ( Fig 3). Infected tubers are inedible. inedible. are tubers 3). Infected (Fig black. turns later and brown becomes gradually that a leaf of edge the at patch green light a is infection of sign One tubers. and stems leaves, attack can it destroyer’; infestans Phytophthora name The Symptoms a as known is hyphae of group A cytoplasm. the in nuclei many have called that structures thread-like of up made fungus is It Oomycetes. ‘true’ class a be to infestans considered longer no Although Structure and Classification 1860s. the in Bary de Anton scientist German by the unveiled eventually was fungus the of view cycle life full The unpopular afungus. by caused the was it that took others the while weather, the natural as to such due was causes it that maintained of group level one certain controversy; a to led scientific This cause. underlying the major a establish was to there search 1845 in disease the of outbreak initial the Following years. hundred loss. a economic significant cause lasted still can it which of today, effects effect devastating to have such is unlikely blight potato the Although Ireland, in of here cause major a famine was disease blight late century mid-nineteenth the In Disease Blight Late significance, The Search for Cause the of structure, its – blight late on prevention. and cycle life focus classification, will lesson This infestans Phytophthora fungus, the by caused blight, late these, Of fungi. and bacteria, This flowers. and leaves producing eventually tubers, the from ground the tubers planting by grown are Potatoes baking, roasting, mashing, steaming, boiling, andchipping crisping. Rooster. for is and It acceptable market. Irish Cara the very on variety Record, successful most Pink, the been has Kerr’s Rooster Wonder, Golden potato, of varieties including different many are in There 2007. worth in was €140m and of ha excess 20,000 of area an occupies crop potato Irish The Classification • • to: able be should student the section, this completing On Learning Outcomes • • • • • • • • • • Learning PointsGeneral 3.6.1 – Vegetative propagation: asexual reproduction, in terms of the of terms in reproduction, asexual propagation:Vegetative 3.6.1– anexample as potato the Organs- Storage Food Plant – Modified 3.3.2 fungi. of nature Eukaryotic Fungi: 3.1.9 of –Nature Economic The forms. parasitic and 3.1.4 –Saprophytic –Fungi nature. in fungi and bacteria of Distribution 3.1.2 –Micro-organisms: classification: of system kingdom Five Organisms: of 3.1.1Diversity – 3.1 Unit causing in parasitism of Role H1.4.11 Relationships: –Ecological 1.4 Unit Biology Certificate Leaving ReferenceSyllabus mycelium Understand the classification of potato blight, Phytophthora Phytophthora blight, potato of classification the Understand Ireland. in potato the of importance economic the Appreciate Describe the procedure used to produce new potato varieties. potato new produce to used procedure the Describe potato. of varieties blight-resistant for search the Describe cycle. life the on impact they how and methods control the Outline infestans. Phytophthora of cycle life the of understanding an Show blight. of symptoms the Outline infestans. Phytophthora of structure the Describe infestans. Though no longer classified as a true fungus, Phytophthora Phytophthora fungus, true a as classified longer no Though the search in here the 1840s, crop of the potato the failure Following of number a and significant the very is crop in potato the diet Economically, our of part important an became first potato The hyphae and reproduction by means of spores. sharesinfestans some fungal features, notably the production of began. blight potato of cause the for namewhose Latin is Phytophthora infestans. blight, late including parasites, many by attack to susceptible is crop potato the However, nationwide. grown are varieties different seventeenth century. vegetatively propagated vegetatively is classified as a eukaryotic as classified is potato and also the blight. the also and potato storage. food for modified astem of of fungi. importance Animal. and Plant Fungi, (Protoctista), Protista Monera, disease and controlling populations. . The species is characterised by having a multi-nucleate multi-nucleate a having by characterised is species The . (Mont.) de Bary, is the most important. important. most the is Bary, de (Mont.) motile zoospores motile crop is subject to attack by viruses, viruses, by attack to subject is crop Phycomycete which belongs to the the to belongs which Phycomycete literally means ‘plant infecting infecting ‘plant means literally in the soil. Shoots grow up above above up grow Shoots soil. the in .

Phytophthora Phytophthora hyphae hyphae outbreaks of the disease in any year. a form of would method new such as and years 10 over for soil the in survive also can greater in result could which pathogen the in variation genetic produce will oospore Sexual an of production the in resulting Ireland. an of in reproduction follows fertilisation rare extremely is this though sexually, reproduce also can fungus The Reproduction Sexual P. of infestans cycle life the follow to below diagram the Use infection. initial initial the following the another to crop one from and of crops within air-borne days rapidly 4-5 multi-cycle, within This sporangia of infection. crop fresh a with stomata the through emerge sporangiophores the conditions, favourable Under by followed is Germination temperatures. higher ( plant host the to attachment by favoured is of periods below to exposure 100C while temperatures germination direct by short favoured is germination Indirect zoospores. motile of by means indirectly or tube agerm of means by directly germinate can Sporangia disease. the of spread where they insects, orleading germinate directly indirectly to further and rain wind, by plants healthy to spread be can sporangia These sporangia were produced. the where length its along swellings periodic by identified sporangiophore can be sporangiophore a of tip the on borne are that thin-walled, of sporangia means lemon-shaped, by (vegetatively) infestans Under normal conditions P. Cycle Life Phytophtora life cycle 2Phytophtora Fig. oogonium . Sexual reproduction reproduces 2-8 1-3 μm) 12-23 × (21-38 virulence by an an by branch. The The branch. over-wintering , aggressiveness or or aggressiveness , f) e) d) c) b) a) True/False Questions g) h) i) j) antheridium 4. 3. 2. 1. Activities Student • • • • •

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Check your answers to these questions on www.sta.ie on questions these to answers your Check fungus atrue not is blight Potato hyphae of agroup for term acollective is A mycelium food with swollen roots are Potatoes 1845 in Ireland in famine of cause amajor was blight Potato Italy from Ireland to brought first were Potatoes apathogen of example an is P. infestans blight potato in occur not does reproduction Sexual better grow afungus makes A fungicide attack blight to susceptible are potato of varieties Resistant potato of variety anew produce to 15 years takes It At what time of the year does late blight infect potato crops? Find Find crops? potato infect blight late does year the of time what At all of list a make and shop vegetable or supermarket local a Visit Grow a potato plant from a tuber in a ‘grow bag’ or large plant pot. plant large or bag’ a‘grow in atuber from plant apotato Grow 1845- in Ireland in Famine the in blight late of role the Research out what weather conditions favour the spread of potato blight. potato of spread the favour conditions weather what out internet. the using varieties different these of properties resistant blight the Research on are sale. that of potato varieties different the to current statistics. theof Famine time the from figures Census Irish the Compare time. the at population Irish the on famine the of effect the to Refer 1846. Selective breeding is a means of producing new varieties of blight- new is varieties a of breeding means producing Selective some and developed been have potato of varieties 33 Ireland In of development the is blight late against defence of line second A disable or kill to designed are that chemicals are Fungicides of the Knowledge life cycle the of development late facilitates blight resistant potato plants. blight. late to resistance excellent show potato. of varieties resistant pathogenic fungi. parasite. the of control of methods successful of encystment of the fungus and could lead to earlier earlier to lead could and fungus the of

Spores present on the leaves at the time of can be harvest a serious Plant resistant varieties of potato. of varieties resistant Plant Avoid planting infected tubers since the disease can over-winter in in over-winter can disease the since tubers infected planting Avoid Spraying the leaves on a regular basis with specific specific with basis regular a on leaves the Spraying Good protect the foliage from infection, see below corrosive solution such as sulfuric acid. sulfuric as such solution corrosive a with by spraying done be can This harvest. before 3 weeks least at off burned be should foliage the Therefore infection. tuber of source the tubers. season helps to prevent infection of the tubers. the of infection prevent to helps season systemic earthing up earthing Potato Blight Potato fungicides. The annual cost of late blight control is in in is control blight late of cost annual The fungicides.

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(i) 2. 1. Questions Style Examination the spread of(ii) tuber to Describe the an from fungus a infected tuber 4. 3. two ways State (iii) in the of may which spread blight potato be reduced.

The National Botanic Gardens in Dublin played a key role in in role key a played Dublin in Gardens Botanic National The potato of varieties different three thirty years forty past the Over is not a tuber it a root; is in potato fact underground, found Although Central of parts of outside unknown was potato the AD 1500 Before by has 2008 been as the designated Nations United the International great Irish Famine. the Irish great during infection blight potato the of source the investigating Carlow. Park, Oak at Centre Research Crop Teagasc the at developed been have reproduction. asexual of organ capable also storage is that food special a is It stem. modified underground an and South America. website: www.potato2008.org following the on found be can information More Potato. the of Year Which variety has the least effective tuber and foliage foliage and tuber effective least the has variety Which (d) (c) (b) (a) words. underlined the of meaning the Give may be in found the leaves infestans of Phytophthora The mycelium (b) (a) Using Table 1 in the Lesson decide which variety you would pick pick would you variety which decide Lesson the Table 1in Using of choice the on decide to have you and grower potato a are You Name developed. be may potato of varieties resistant how Outline blight in the following year. following the in blight in found are mycelia potatowinter tubers. These tubers are responsible for the appearance of the During intervals. at haustoria out put and leaf the through grow hyphae The plants. potato infected of in each of the following cases: following the of each in grow. to varieties potato Ireland. in developed been have that potato of varieties four cycle. life its or infestans Phytophthora on method each of effect the State produced in the following growing season. . protectant, translaminar

For further examples of examination questions questions examination of examples further For resistance? resistance. foliage and tuber best the has that A variety resistance. tuber than resistance foliage better has that A variety resistance. foliage than resistance tuber better has that A variety nature. of scheme overall the in parasites of role the State parasite. term the Explain fungicides to to

check from the making of the initial cross until the new variety can be be can variety new the until cross initial years. fifteen the about takes grown commercially of making variety the potato new a from multiplying and testing breeding, of process The is process of type This breeding. propagated. selective as known vegetatively are they fungus the found, to are resistance good show that plants potato When blight. to resistance for tested are they while the All underground. tubers produce and grow hybrids The (hybrids). parents both of combination genetic a are grow that plants potato new The out. planted seedlings the and sown then are produced are that seeds The cross. initial the as known is This variety). other of the part on it female to the dusting and variety one from www.sta.i legislation. safety and health and environmental under obligations industry’s the and pathogen. control disease of area the in the the with particularly industry, potato closely in work who variation advisors technical genetic has also and Teagasc efficacy fungicide to the host, the reference and with special pathogen the environment of interaction the on focused is latter The control. blight breeding late and potato of areas the in are projects in current and Centre, Carlow Research Crops the at conducted is research Potato as such crops environment. rural the of protection the tillage of and produce the of safety and quality competitiveness the ensure to and potatoes, the increase to is tillage the facing challenges One and sector of rural communities. the objectives the organisation’s on focused firmly is Teagasc 300 and scientists roles. advisory and 200 training in development staff over specialist other many and rural research, in technicians employs with Teagasc and industries agencies. locations food hundred and a agriculture over at the of work sectors all with in work They country. the throughout staff industry food 1,500 and Over agriculture Ireland. the for services training and Teagasc www.teagasc.ie and the many scientific projects they are involved in at there work who people Teagasc, the about out Find is a state organisation that provides research, advisory advisory research, provides that organisation state a is e SCIENCE TECHNOL SCIENCE TECHNOL ACTION IN ACTION

AN D SECOND EDITIONFOURTH vegetative reproduction, virulence, zoospore. parasite, over-winter, sporangiophore, systemic, translaminar, tuber, vegetative oogonium, propagation, sporangia, breeding, selective protectant, photosynthesis, mycelium, pathogen, micrometer, hyphae, encystment,fungicide, haustorium, gametangium, hybrid,eukaryotic, hectare, earthing-up, cross, bi-flagellate, asexual, antheridium, terms? following the of meaning the recall you Can retention. and recall for aid apowerful is terminology the Revising Revise The Terms lichens. in exists that fungus a and alga an between relationship of kind the word describe the to symbiosis coined and lichens of stages developmental the studied He of wheat. parasites are that of fungi study extensive out carried He also potatoes. of parasites are further that fungi of a number a spent studying and years fifteen 1861 in fungi on work first his published Bary De and forms the seemed to different species. be different developed they as dramatically quite form life whole changed organisms many the sexual because cycle observe to describe essential to was first it that realised He fungi. in reproduction the was He he plants. 1853 of parasites fungal common of In study are which rusts on Heidelberg. abook his published at began Bary medicine de 1848 In fungi. of classification and physiology the of study the in specialised who surgeon, German botanist, microbiologist and mycologist, a was Bary de Anton (1831–1888) Bary de Anton Heinrich Biographical Notes OG OG Check the Glossary of Terms for this lesson at www.sta.i at lesson Terms of this for Glossary the Check • • • •

A ‘resistance gene’ that is effective against all known strains of of strains known all against effective is that gene’ ‘resistance A to Potato” “Irish the as known is potato the countries many In Ridging Axona Sarpo is and Mira oftenSarpo as such potatoes of varieties used New to reduce tuber contamination by the blight has been identified and successfully copied from a wild wild a from potato, the copied of successfully relative and identified been has blight Ipomoea batatas. potato, sweet the from it distinguish blight. This usually involves piling soil or mulch around the stems stems the around mulch or the tuber. to get to soil travel to farther has piling pathogen the that so potato involves the of usually This blight. infestation. heavy of areas in even blight to resistance great show into the genome of cultivated varieties of the potato. the of varieties cultivated of genome the into Y Y

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OG OG Y Y e • • • • • • • • to: able be should student the section, this completing On Learning Outcomes • • • • Learning PointsGeneral 3.6.1 – Vegetative propagation: asexual reproduction, in terms of the of terms in reproduction, asexual propagation:Vegetative 3.6.1– anexample as potato the Organs- Storage Food Plant – Modified 3.3.2 fungi. of nature Eukaryotic Fungi: 3.1.9 of –Nature Economic The forms. parasitic and 3.1.4 –Saprophytic –Fungi nature. in fungi and bacteria of Distribution 3.1.2 –Micro-organisms: classification: of system kingdom Five Organisms: of 3.1.1Diversity – 3.1 Unit causing in parasitism of Role H1.4.11 Relationships: –Ecological 1.4 Unit Biology Certificate Leaving ReferenceSyllabus Describe the procedure used to produce new potato varieties. potato new produce to used procedure the Describe potato. of varieties blight-resistant for search the Describe cycle. life the on impact they how and methods control the Outline infestans. Phytophthora of cycle life the of understanding an Show blight. of symptoms the Outline infestans. Phytophthora of structure the Describe Phytophthora blight, potato of classification the Understand Ireland. in potato the of importance economic the Appreciate infestans. Though no longer classified as a true fungus, Phytophthora Phytophthora fungus, true a as classified longer no Though the search in here the 1840s, crop of the potato the failure Following of number a and significant the very is crop in potato the diet Economically, our of part important an became first potato The hyphae and reproduction by means of spores. sharesinfestans some fungal features, notably the production of began. blight potato of cause the for namewhose Latin is Phytophthora infestans. blight, late including parasites, many by attack to susceptible is crop potato the However, nationwide. grown are varieties different seventeenth century. potato and also the blight. the also and potato storage. food for modified astem of of fungi. importance Animal. and Plant Fungi, (Protoctista), Protista Monera, disease and controlling populations. b) a) True/False Questions d) c) f) e) g) i) h) j) 2. 1. Activities Student 4. 3. • • • • •

Check your answers to these questions on www.sta.ie on questions these to answers your Check Italy from Ireland to brought first were Potatoes food with swollen roots are Potatoes 1845 in Ireland in famine of cause amajor was blight Potato fungus atrue not is blight Potato hyphae of agroup for term acollective is A mycelium apathogen of example an is P. infestans better grow afungus makes A fungicide blight potato in occur not does reproduction Sexual potato of variety anew produce to 15 years takes It attack blight to susceptible are potato of varieties Resistant eerh h rl o lt bih i te aie n rln i 1845- in Ireland in Famine the in blight late of role the Research At what time of the year does late blight infect potato crops? Find Find crops? potato infect blight late does year the of time what At all of list a make and shop vegetable or supermarket local a Visit pot. plant large or bag’ a‘grow in atuber from plant apotato Grow to current statistics. theof Famine time the from figures Census Irish the Compare time. the at population Irish the on famine the of effect the to Refer 1846. out what weather conditions favour the spread of potato blight. potato of spread the favour conditions weather what out internet. the using varieties different these of properties resistant blight the Research on are sale. that of potato varieties different the Selective breeding is a means of producing new varieties of blight- new is varieties a of breeding means producing Selective some and developed been have potato of varieties 33 Ireland In of development the is blight late against defence of line second A disable or kill to designed are that chemicals are Fungicides of the Knowledge life cycle the of development late facilitates blight resistant potato plants. blight. late to resistance excellent show potato. of varieties resistant pathogenic fungi. parasite. the of control of methods successful of Potato Blight Potato T T T T T T T T T T F F F F F F F F F F • YouDid Know? • • • • mycelium and bi-flagellate and mycelium was potato the time, that at today. case the still is This Ireland. in grown even extensively that suggest, This would Irish. the for food of source many a as find potato the to can one references century seventeenth the of middle the By Cork. Co. Youghal, in 1623 as early as toll potatoes a on to (tax) and 1606 in Down Co. in grown being potatoes to refer records Historical their on America. South from Ireland voyages return visited whom of both Raleigh, Walter Sir by or Drake Francis Sir by brought were they claim Some Ireland. in arrived first potatoes how or when exactly knows one No and later turns black. ( Fig 3). Infected tubers are inedible. inedible. are tubers 3). Infected (Fig black. turns later and brown becomes gradually that a leaf of edge the at patch green light a is infection of sign One tubers. and stems leaves, attack can it destroyer’; infestans Phytophthora name The Symptoms a as known is hyphae of group A cytoplasm. the in nuclei many have called that structures thread-like of up made fungus is It Oomycetes. ‘true’ class a be to infestans considered longer no Although Structure and Classification 1860s. the in Bary de Anton scientist German by the unveiled eventually was fungus the of view cycle life full The unpopular afungus. by caused the was it that took others the while weather, the natural as to such due was causes it that maintained of group level one certain controversy; a to led scientific This cause. underlying the major a establish was to there search 1845 in disease the of outbreak initial the Following years. hundred loss. a economic significant cause lasted still can it which of today, effects effect devastating to have such is unlikely blight potato the Although Ireland, in of here cause major a famine was disease blight late century mid-nineteenth the In Disease Blight Late significance, The Search for Cause the of structure, its – blight late on prevention. and cycle life focus classification, will lesson This infestans Phytophthora fungus, the by caused blight, late these, Of fungi. and bacteria, This flowers. and leaves producing eventually tubers, the from ground the tubers planting by grown are Potatoes baking, roasting, mashing, steaming, boiling, andchipping crisping. Rooster. for is and It acceptable market. Irish Cara the very on variety Record, successful most Pink, the been has Kerr’s Rooster Wonder, Golden potato, of varieties including different many are in There 2007. worth in was €140m and of ha excess 20,000 of area an occupies crop potato Irish The Classification

(i) 2. 4. 3. two ways State (iii) in the of may which spread blight potato be reduced. the spread of(ii) tuber to Describe the an from fungus a infected tuber 1. Questions Style Examination mycelium

2008 has been designated by has 2008 been as the designated Nations United the International Before 1500 AD the potato was unknown outside of parts of Central Central of parts of outside unknown was potato the AD 1500 Before Although found underground, a potato tuber is not a tuber it a root; is in potato fact underground, found Although Over the past forty years thirty three different varieties of potato potato of varieties different three thirty years forty past the Over The National Botanic Gardens in Dublin played a key role in in role key a played Dublin in Gardens Botanic National The website: www.potato2008.org following the on found be can information More Potato. the of Year and South America. that is also capable of asexual reproduction. asexual of organ capable also storage is that food special a is It stem. modified underground an Park, Carlow. Carlow. Park, Oak at Centre Research Crop Teagasc the at developed been have great Irish Famine. the Irish great during infection blight potato the of source the investigating Which variety has the least effective tuber and foliage foliage and tuber effective least the has variety Which (d) (c) (b) may be in found the leaves infestans of Phytophthora The mycelium (a) pick would you variety which decide Lesson the Table 1in Using of choice the on decide to have you and grower potato a are You Name developed. be may potato of varieties resistant how Outline words. underlined the of meaning the Give (b) (a) blight in the following year. following the in blight in found are mycelia potatowinter tubers. These tubers are responsible for the appearance of the During intervals. at haustoria out put and leaf the through grow hyphae The plants. potato infected of in each of the following cases: following the of each in grow. to varieties potato Ireland. in developed been have that potato of varieties four cycle. life its or infestans Phytophthora on method each of effect the State produced in the following growing season. vegetatively propagated vegetatively

is classified as a eukaryotic as classified is For further examples of examination questions questions examination of examples further For resistance? A variety that has the best tuber and foliage resistance. foliage and tuber best the has that A variety resistance. tuber than resistance foliage better has that A variety resistance. foliage than resistance tuber better has that A variety nature. of scheme overall the in parasites of role the State Explain the term parasite. term the Explain . The species is characterised by having a multi-nucleate multi-nucleate a having by characterised is species The . (Mont.) de Bary, is the most important. important. most the is Bary, de (Mont.) motile zoospores motile crop is subject to attack by viruses, viruses, by attack to subject is crop check Phycomycete which belongs to the the to belongs which Phycomycete literally means ‘plant infecting infecting ‘plant means literally in the soil. Shoots grow up above above up grow Shoots soil. the in www.sta.i .

e Phytophthora Phytophthora hyphae hyphae outbreaks of the disease in any year. a form of would method new such as and years 10 over for soil the in survive also can greater in result could which pathogen the in variation genetic produce will oospore Sexual an of production the in resulting Ireland. an of in reproduction follows fertilisation rare extremely is this though sexually, reproduce also can fungus The Reproduction Sexual P. of infestans cycle life the follow to below diagram the Use infection. initial initial the following the another to crop one from and of crops within air-borne days rapidly 4-5 multi-cycle, within This sporangia of infection. crop fresh a with stomata the through emerge sporangiophores the conditions, favourable Under by followed is Germination temperatures. higher ( plant host the to attachment by favoured is of periods below to exposure 100C while temperatures germination direct by short favoured is germination Indirect zoospores. motile of by means indirectly or tube agerm of means by directly germinate can Sporangia disease. the of spread where they insects, orleading germinate directly indirectly to further and rain wind, by plants healthy to spread be can sporangia These sporangia were produced. the where length its along swellings periodic by identified sporangiophore can be sporangiophore a of tip the on borne are that thin-walled, of sporangia means lemon-shaped, by (vegetatively) infestans Under normal conditions P. Cycle Life

Phytophtora life cycle 2Phytophtora Fig. oogonium . Sexual reproduction reproduces 2-8 1-3 μm) 12-23 × (21-38 virulence by an an by branch. The The branch. over-wintering , aggressiveness or or aggressiveness , vegetative reproduction, virulence, zoospore. parasite, over-winter, sporangiophore, systemic, translaminar, tuber, vegetative oogonium, propagation, sporangia, breeding, selective protectant, photosynthesis, mycelium, pathogen, micrometer, hyphae, encystment,fungicide, haustorium, gametangium, hybrid,eukaryotic, hectare, earthing-up, cross, bi-flagellate, asexual, antheridium, terms? following the of meaning the recall you Can retention. and recall for aid apowerful is terminology the Revising Revise The Terms lichens. in exists that fungus a and alga an between relationship of kind the word describe the to symbiosis coined and lichens of stages developmental the studied He of wheat. parasites are that of fungi study extensive out carried He also potatoes. of parasites are further that fungi of a number a spent studying and years fifteen 1861 in fungi on work first his published Bary De and forms the seemed to different species. be different developed they as dramatically quite form life whole changed organisms many the sexual because cycle observe to describe essential to was first it that realised He fungi. in reproduction the was He he plants. 1853 of parasites fungal common of In study are which rusts on Heidelberg. abook his published at began Bary medicine de 1848 In fungi. of classification and physiology the of study the in specialised who surgeon, German botanist, microbiologist and mycologist, a was Bary de Anton (1831–1888) Bary de Anton Heinrich Biographical Notes antheridium Check the Glossary of Terms for this lesson at www.sta.i at lesson Terms of this for Glossary the Check • • • • asexually

Spores present on the leaves at the time of can be harvest a serious Plant resistant varieties of potato. of varieties resistant Plant Avoid planting infected tubers since the disease can over-winter in in over-winter can disease the since tubers infected planting Avoid Spraying the leaves on a regular basis with specific specific with basis regular a on leaves the Spraying Good protect the foliage from infection, see below corrosive solution such as sulfuric acid. sulfuric as such solution corrosive a with by spraying done be can This harvest. before 3 weeks least at off burned be should foliage the Therefore infection. tuber of source the tubers. season helps to prevent infection of the tubers. the of infection prevent to helps season systemic , and introduced introduced , and earthing up earthing

fungicides. The annual cost of late blight control is in in is control blight late of cost annual The fungicides. OG OG parasite around the potato plants during the growing growing the during plants potato the around Y Y e and the conditions that affect its growth. The The growth. its affect that conditions the and . protectant, translaminar fungicides to to

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