Compendium of Potato Diseases - (PDF, 101 mb) - USAID

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Each ae--ium is cupulate. 0.3-0.5 mm in diameter, with a colorless periderin. Aeciospores are angularly globoid or ellipsoid, I(r-21 X 20-23 , in. Epidemiology The source of inoculum is probably cultivated potato, which is grown under irrigation in the drier season. Because this disease occurs below the elevation of severe frosts, tile causal fungus may survive year around in plants and 'or debris, but no research has been done on the overwintering of the pathogen. Other Hosts Potato is the only well verified host. Control Although Peruvian rust can be very damaging and recurs every rainy season in some localities, it is not widespread and thus not considered an important disease. No research on its control has been underta ken. Selected References ABBOTT, F. V. 1931. Further notes on plant diseases in Peru. Phytopathology 21:1)61-11)71. ARTII IR, ,. C. 1929. las royas de los vegetales (Uredinales) del Peril. Est. Exp. Agric. Soc. Nac. Agrar. Lima. Peru. Bol. 2. 14 pp. BIIRI ICWA. I'.. and .1. OR.I I-IA. 1968. Estudios fisiol6gicos (Ie I'td(ina pi/iteria a Ilenn. ca usta lt d Ii ioa v de IaIpapa (Solattiom ttheroom, I..) Fitotecnia Lahinoamericana 5:81-88. I)IAZ, .1. R., and .1. CIII-VERRIA. 1963. Chemical control of l'o icia pitieriana on 47:800--801. polatoes in Ecuador. Plant Dis. Rep. FR ENCI. F. R.. II. TOR RES. I. A.de IC()CFII A, . SAILAZAR, C. FRIBOtRG. F.N.FERNANI)EZ. A. MARTIN,.J. FRANCO. M. M. (l(eSCUIRRAII. I. A. IIERRERA. C. VISF., I.. l.AZOand 0. A. I DAl) l. O. 1972. EnfernedLades de Ia Papa en el Perti. Bol. Tecn. 77. Est. Exp. Agr'.. l.a Molina. 36 p lIEN NIN(iS. I'. I9d4. Linige neue pil/c aus (ostarica utid Paraguay. Iledwigia 43:147-149. IIIURSION. II. 1). 1973. Threatening plant dise,.es. Ann. Rev. IPhytopathol. 11:27-52, 66 (P~repared by I'. R. French) sintuhaneousl present in leaf spots, severely defoliating potatoes in Peru. C(haetomiwnu spp. leaf spot, superficially resembling early blight but without the targetlike markings, is reported in South Dakota. Necrosis and chlorosis develop around points of mechanical injury. Selected References COOK, A. A. 1954. A foliage diseaseof potato induced by Chaetoioiunt species. Plant Dis. Rep. 38:403-404. FABRICATORE, .. 1953. Volanon tuherosun, ospite casuale di un Ietero.,wrihon. Rev. Appl. Mycol. 1953:504. JONES, W.. and if. S. MacL.EOl). 1937. Armillaria dry rot of potato tubers in British Columbia. Am. Potato .1.14:215-217. KUIFUSS, K. II. 1957. (Ionostachys arau'ariae Corda var. rosea Preuss an faulenden Kartoffelknollen. Nachrichtenbl. Pflan /enschutz. 1). I). R. 11:144-146. NYAK. M. L..1964. A new organism causing dry rot of potatoes. Sci. Cult. 30:143-144. PF1T1NA RI. C. 1949. A/ione patogena della ('lowsoach'r.s ara'ariae Corda var. ro.wa Preuss su tuberi di Solanwm uberostui. Ann. Sper. Agriar. 3:665-672. RIEHI.E, i. 1). 1941. A Xylaria tuber rot of potato. Phytopathology 31:936-939. SAIAI., 1). 1967. A newdisease of potato tubers caused by Gulmaniella hooicola Barron. Curr. Sci. 36:645-646. VESSEY, J. C. 1975. Some potato diseases of the Peruvian humid tropics. Plant Dis. Rep. 59: i004-1007. (Prepared by W. J. Hooker) Mycorrhizal Fungi The role of these obligate symbionts in potato growth and particularly their relation to tuberization has been extensively investigated. Only recently has their beneficial effect on potatoes been established. Inoculation in the root hair region with the endomycorrhizal fungus, Glotnus .fasciculatus, increased tuber yields ant total plant weight. Selected References GRAHAM. S. 0.. N. E.GREEN. and ..W. HENDRIX. 1976. The Miscellaneous Diseases influence of vesicular-arbuscular mycorrhizal fungi on growth and tuberization of potatoes. Mycologia 68:925-929. PHILLIPS. J. M., and 1). S. HAYMAN. 1970. Improved procedures Tuber Rots for clearing roots and staining parasitic vesicular-arbuscular In Germianyv and Italy. (Ihmo.otachrs araariaevar. rosea mycorrhizal In IalyCermny fungi for rapid Chrwsuhv~ assssment nd of infection. arucuirn'var Trans. Br. roesMvcol. tuber rot occasionally Soc. 55:158-161. causes severe losses in storage following bad weather during harvest. Dark necrotic areas on tubers are (Prepared by W. J.Hooker) surrounded by white mycelium with abundant conidia. Armillaria dry rot isa minor problem in northern areas where potatoes are produced on recently cleared land. Armillaria ,n.lea Vahl. ex Fr. causes hard brown, roughened areas some- Principles of Foliage what corky in texture. L.esions are usually shallow, with dark brown to black rhizomorphs attached to .:uch areas. Fungicide Application Xylaria tube- • it oc -urs in calcareous marl soils of Florida. Black rhizomo. ., tfireadlike to 3 mm thick, become firmly In most parts of the world, sprays have superceded attached dusts to in the tuber surface. In the field, tuber invasion slowly control of foliage diseases of potato. Dusts are progresses easily and as more or less semicircular lesions. The problem, of quickly applied without premixing with water, and dusters are minor importance, develops on recently cleared land. usually cheaper, lighter, and simpler in construction and Gilmaniella humicola causes minute brownish necrotic spots, maintenance than sprayers. However, dusts drift easily, do not 2-6 mm in diameter, around lenticels and eyes. L.esions remain adhere well to foliage in the absence of moisture, shallow. and are Eyes not are killed, making tubers unfit for seed. well suited to large-scale outdoor crop protection. On the other Cyiudlrocarpontonkinesis dry rot develops during the rainy hand, sprays are less subject to drift, provide season more in India uniform as brown patches on skin, later with white coverage, and stick better to foliage than dusts do, but accurate mycelium in or on affected tissue, measurement and mixing of ingredients are essential to their te'erosporiutn sp., usually found on potato leaves, also effectiveness. causes lesions on tubers. With few exceptions, the fungicides used to control foliage diseases of potato are protectant in their action. Leaf This Spots means they must be applied to foliage before orat the same time as inoculum Periconia sp., IXetuspaerulinasp., and Diid'mella sp. are is deposited in order to prevent fungous spore germination,
penetration, and subsequent disease development. Because protectant fungicides are not absorbed and translocated through the plant to any significant degree, they must be applied uniformly to as much of the foliage as possible. This implies uniformity both in horizontal distribution of fungicide across the spray swath and vertical distribution (penetration) through the plant canopy. Coverage of both upper and lower leaf surfaces isalso essential. To achieve optimal coverage, attention should be paid to the following: use of the correct spray volume and pressure for which a sprayer has been designed; proper functioning of the sprayer as determined by cleanliness, wear of nozzle orifices, height of boom, accuracy of pressure gauge; spraying when the air is still; and not extending swath width beyond that specified for the sprayer. Traiditional hydraulic boom sprayers that apply large voluimes (70t 1170r L ha, 75-125 g A of dilute spray under high pressure (approximately 28 kg cm, 400 psi) provide good horizontal and vertical distribution of fungicides. However, weight, high cost, large water requirement, and frequent need for filling have decreased their popularity in recent years. The present, trend is towards low pressure (approximately 7.0-8.8 kcn)-15pilwvlm(apoiaey45Lh,0 kg cm -100-125 psi), low volume (approximately4651 ha,50 g,A or less) spraying, either with hydraulic or airblast (atomizing) machines. These can be effectively used if the manufacturer's recommendations are followed, Spraying by aircraft has several advantages such as speed, saving of labor, ability to be used in fields too wet for ground equipment, absence of yield loss due to sprayer tracks, reduced spread of virus diseases, and low water requirements (usually 28-47 1. ha, 3-5 g A). These advantages have increased accetance of aircraft application particularly among large growers, But again, certain disadvantages must be considered, such as wind iterference and risk of drift, unsuitability of small, irregularly shaped or topographically uneven fields, the hazard of physical obstacles, relatively poor vertical distribution of spray through the plant canopy, and sparse deposition of d3scr,;et particles of concentrated fungicide. This last makes it essential that fungicide deposits be redistributed, i.e., transferred from their original landing sites to unprotected leaf areas by moisture in the form of dew, rain, or irrigation. Although the addition ofadjuvantsto fungicide sprays has been promoted to improve redistribution, most fungicide formulations have adequate spreadability without being supplemented with such materials. To provide as complete a protective blanket as possible, fungicide sprays must be applied at regular intervals to protect newly-expanded foliage and to supplement fungicide activity lost to dilution, photodegradation, oxidation, etc. Frequency of application depends n weather conditions, presence of disease in the vicinity, tena,:ity of the fungicide, varietal resistance, sprayer capability, and other factors. The usual interval employed by growers ranges from 5to 14 days. In certain areas, disease forecasting systems are used to determine spray intervals, I se ofthe correct aimount offungicide per unit area isvital to effective disease control. This requires careful attention to spr,.ycr calibration and maintenance. Calibration means determining how much fungicide is applied by a sprayer to a particular area. In summary, the four basic requirements for success are to apply the right chemical in the right amount at the right time in the right way to obtain maximum coverage. Selected References IIJRSFA I.I. .1.G. 1956. Principles of Fungicidal Action. Chronica Botanica Co., Waltham, ME. 231 pp. MARlIN. II. 1959. The Scientific Principles of Crop Protection. 4th ed. EIdward Arnold, Ltd.. London. 359 pp. 10RGESON,1). C.. ed. 1967. hIngicides An Advanced Treatise, Vol. I. Academic Press. New York. 697 pp. (Prepared by 0. Schultz) Tuber Seed Treatment Chemical treatment of seed tubers before planting is neithera cure-all nor a replacement for the use of high quality seed, properly stored and handled. Rather, it isinexpensive insurance that partially protects seed from invasion by microorganisms present in the soil and on the tuber surface. Unfortunately, it does not kill microorganisms present within seed. Possible benefits of seed treatment are: I) control of storage diseases such as Fusarium dry rot, 2)control of seed piece decay when cut seed has to be held for an extended period before planting. 3) control the soil (usually ol + seed piece decay inthsoluuay caused by Fusarium spp.) when planting is done under adverse soil conditions (cool and wet) that impair suberization of the cut surfaces, and 4) partial control of diseases such as Rhizoctonia stem canker, scab, Verticillium wilt, and blackleg. Prestorage treatment of seed, a relatively recent development, usually involves application of fungicides (e.g., thiabendazole) in the form of a fine mist as tubers enter the storage structure. Seed treatment after storage and before planting is most commonly don: by dusting with rotating drum dusters, which generally provide better coverage than do the shaker types of treaters. Several ethylenebisdithiocarbamate fungicides are useful for dip treatment of seed tubers. but they are not com monly applied in tis manner. When whole seed is planted, or when cut seed is planted in a warm, moist seedbed promptly after cutting, whole tubers may be surface disinfested by dusting or dipping. This is only partially effective in controlling diseases such as Rhizoctonia stem canker, scab, and Verticillium wilt because their causal agents are commonly soilborne. Where cut seed is predominantly used, treating seed immediately after, rather than before, cutting is advisable (dusts. are preferred). This protects the cut tuber surfaces from invasion by soilborne pathogens such as Fusarium spp. and provides partial surface disinfestation. Cut seed, whether treated or not, should be planted immediately. If this is impossible, it should he stored in open containers such as potato crates stacked to provide ample ventilation. Burlap bags should be only half filled and also stacked forventilation. Cut seed should be held at 10-16Cand high relative humidity (85-90%) for three to four days to allow wound cork to form over cut surfaces. If further stoage is necessary, temperatures can be dropped to 5 C, but seed should be warmed again before planting to ensure vigorous sprouting. Insects should be excluded from cut seed, particularly adults of the seed corn maggot. Cut seed held for some time before planting may develop considerable seed piece decay and give poor stands. Selected References BOYI). A. E. W. 1975. Fungicides for potato tubers. Proc. 8th British Insecticide and Fungicide Conf. 3:1035-1044. MOSHER, P. 1972. Treating seed potatoes for disease control. Spudlines. April 1972. Univ. of Maine. 3 pp. (Prepared by 0. Schultz) 67
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, ,. ,o . ; , . o , . r. , -' .L ,
Page 3 and 4:
Compendium of Potato Diseases W. J.
Page 5 and 6:
In memory ofimy respected colleague
Page 7 and 8:
Acknowledgments Planning Committee
Page 9 and 10:
Introduction 1 Potato Disease 1 The
Page 11 and 12:
A potato disease is an interaction
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Fig. 1.A, Lower portion of young po
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+q I B Fig 4. Natural openings in a
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Part I. Disease in the Absence of I
Page 19 and 20:
more heavily in the vascular region
Page 21 and 22:
the air temperature when tubers are
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iiO A B 'D C Fiq. 14 Second growth:
Page 25 and 26:
identifying tissue bruised by black
Page 27 and 28:
Internal Sprouting multiple sprouts
Page 29 and 30:
conditions permits normal leaf deve
Page 31 and 32:
Epidemiology Oxidant injury is pres
Page 33 and 34:
sevritof stnting, chiorosis. loss o
Page 35 and 36:
Selected Reference brown to bronze
Page 37 and 38:
Part II. Disease in the Presence of
Page 39 and 40:
should be planted on land with at l
Page 41 and 42: Control I) Use disease-free tubers
Page 43 and 44: FOI-SO M. D, and I. A. FRIEDMAN. )9
Page 45 and 46: Fungi Powdery Scab liberating powde
Page 47 and 48: Histopathology Sort of sporangia de
Page 49 and 50: any time but generally occurs late
Page 51 and 52: '40 ff .. . '1 f . ."L', . '1 .,. "
Page 53 and 54: A \, 2) Powdery mildew is rarely a
Page 55 and 56: R., Inst.. Kew. Surrey. ngland. 609
Page 57 and 58: TORRES, H.. E. R. FRENCH, and I.. W
Page 59 and 60: d AC D A 0 Fig 53 Gray mold. A, Bot
Page 61 and 62: strands of pigmented hyphae. Sclero
Page 63 and 64: tuber malformation. Roots are also
Page 65 and 66: 1. Giant-hill plants, taller than n
Page 67 and 68: 13. Bacterial soft rot. Erwinia car
Page 69 and 70: 24. Wart. Synchytrium endobioticum
Page 71 and 72: 34. Pleospora herbarum (Stemphylium
Page 73 and 74: 44. Charcoal rot. Macrophomina phas
Page 75 and 76: 55. Leafroll virus. Current season
Page 77 and 78: 67. Mop-top virus. Primary tuber 68
Page 79 and 80: 77. Aster yellows mycoplasma sympto
Page 81 and 82: Symptoms Small, localized, light br
Page 83 and 84: obovoid, and 14-30 X 5-10 pm. Pycni
Page 85 and 86: invaders through the IFusarium lesi
Page 87 and 88: necrosis extending into the tuber t
Page 89 and 90: do not survive drying. Both species
Page 91: cauisal. Tesis Magister Scientiae e
Page 95 and 96: have been demonstrated, including t
Page 97 and 98: In P..floridana,strains of PVY" and
Page 99 and 100: infects certain comnie,-cial stocks
Page 101 and 102: cytoplasm of infected potato cells
Page 103 and 104: WETTER, C. 1971. Potato virus S. No
Page 105 and 106: 3) Resistance has not been identifi
Page 107 and 108: nm), which do code for coat protein
Page 109 and 110: Symptoms AMV may induce Other predo
Page 111 and 112: Disease Cycle I)escriptions of Plan
Page 113 and 114: Selected References KASSANIS, B. 19
Page 115 and 116: Control 1)Avoid locations in wkhich
Page 117 and 118: The "yellows" types of disease, cha
Page 119 and 120: modifying cultural practices and by
Page 121 and 122: immature females in the white or ye
Page 123 and 124: l.aboratory, Control. and Quarantin
Page 125 and 126: They attack many major crops in the
Page 127 and 128: infested areas of North America sev
Page 129 and 130: antennal tb l tuberce u antenna eye
Page 131 and 132: carbon tetrachloride, applied at th
Page 133 and 134: Diagnostic Microbial Structures Scl
Page 135 and 136: Surface and or interior Shades of g
Page 137 and 138: Equivalent Names of Potato Diseases
Page 139 and 140: Common Name Causal Factor Other Nam
Page 141 and 142: Common Name Causal Factor Other Nam
Page 143 and 144:
coalesce-union of similar structure
Page 145 and 146:
many days following removal of the
Page 147 and 148:
Index Abrasions, tuber surfaces. 14
Page 149:
Irost tolerance in. 9 aniligena. 68
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