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Diseases of Corn (syn. Maize) (Zea mays L.)

Gary P. Munkvold, collator (last update: 8/27/17)

BACTERIAL DISEASES

Bacterial leaf blight

Pseudomonas avenae Manns subsp. avenae Manns

       (syns. Acidovorax avenae (Manns) Willems et al. subsp. avenae (Manns)

       Willems et al.; Bacillus avenae (Manns) Burgvits; Pseudomonas alboprecipitans Rosen)

Bacterial leaf streak

Xanthomonas vasicola pv. vasculorum (Cobb) comb. nov.

Bacterial stalk rot

Erwinia carotovora (Jones) Bergey et al. subsp. carotovora (Jones) Bergey et al.

       (syns. Erwinia carotovora (Jones) Bergey et al. f. sp. zeae Sabet; Erwinia

       chrysanthemi Burkholder et al. pv. zeae (Sabet) Victoria et al.; Pectobacterium

       carotovorum (Jones) Waldee emend. Hauben et al. subsp. carotovorum (Jones) Waldee

       emend. Hauben et al.)

Bacterial stripe and leaf spot

Pseudomonas andropogonis (Smith) Stapp

       (syn. Burkholderia andropogonis (Smith) Gillis et al.)

Chocolate spot

Pseudomonas syringae van Hall pv. coronafaciens (Elliott) Young et al.

       (syn. Pseudomonas coronafaciens (ex Elliott) Schaad & Cunfer pv. zeae Ribeiro et al.)

Goss’s bacterial wilt and blight

Clavibacter michiganensis (Smith) Davis et al. subsp. nebraskensis (Vidaver & Mandel) Davis et al.

       (syn. Corynebacterium michiganense (Smith) Jensen subsp. nebraskense

       (Vidaver & Mandel) Carlson & Vidaver)

Holcus spot

Pseudomonas syringae van Hall pv. syringae van Hall

       (syn. Pseudomonas holci Kendrick)

Stewart’s bacterial wilt

Pantoea stewartii (Smith) Mergaert et al. subsp. stewartii (Smith) Mergaert et al.

       (syns. Erwinia stewartii (Smith) Dye; Xanthomonas stewartii (Smith) Dowson)

FUNGAL AND OOMYCETE DISEASES

Downy Mildews

Brown stripe downy mildew

Sclerophthora rayssiae R. G. Kenneth, Koltin & I. Wahl var. zeae Payak & Renfro

Crazy top

Sclerophthora macrospora (Sacc.) Thirum., C. G. Shaw & Naras.

       (syns. Phytophthora macrospora (Sacc.) S. Ito & I. Tanaka; Sclerospora

       macrospora Sacc.)

Graminicola downy mildew

Sclerospora graminicola (Sacc.) J. Schröt.

Java downy mildew

Peronosclerospora maydis (Racib.) C. G. Shaw

       (syn. Sclerospora maydis (Racib.) E. J. Butler)

Leaf splitting downy mildew

Peronosclerospora miscanthi (T. Miyake) C. G. Shaw

       (syn. Sclerospora miscanthi T. Miyake)

Philippine downy mildew

Peronosclerospora philippinensis (W. Weston) C. G. Shaw

       (syn. Sclerospora philippinensis W. Weston)

Rajasthan downy mildew

Peronosclerospora heteropogoni Siradhana, Dange, Rathore & S. D. Singh

Sorghum downy mildew

Peronosclerospora sorghi (W. Weston & Uppal) C. G. Shaw

       (syns. Sclerospora graminicola (Sacc.) J. Schröt. var. andropogonis-sorghi Kulk.;

       Sclersopora sorghi W. Weston & Uppal)

Spontaneum downy mildew

Peronosclerospora spontanea (W. Weston) C. G. Shaw

       (syn. Sclerospora spontanea W. Weston)

Sugarcane downy mildew

Peronosclerospora sacchari (T. Miyake) C. G. Shaw

       (syn. Sclerospora sacchari T. Miyake)

Ear and Kernel Rots

Aspergillus ear rot

Aspergillus flavus Link:Fr.

Aspergillus niger Tiegh.

Aspergillus oryzae (Ahlb.) Cohn

Aspergillus parasiticus Speare

Black kernel rot

Lasiodiplodia theobromae (Pat.) Griffon & Maubl.

       (syn. Botryodiplodia theobromae Pat.)

Cladosporium rot

Cladosporium cladosporioides (Fresen.) G. A. de Vries

       (syn. Hormodendrum cladosporioides (Fresen.) Sacc.)

Cladosporium herbarum (Pers.:Fr.) Link

Diplodia (Stenocarpella) ear rot

Stenocarpella macrospora (Earle) B. Sutton

       (syn. Diplodia macrospora Earle)

Stenocarpella maydis (Berk.) B. Sutton

       (syns. Diplodia maydis (Berk.) Sacc.; Diplodia zeae Lév.)

Fusarium ear rot or pink ear rot

Fusarium spp.

Fusarium oxysporum Schltdl.:Fr.

Fusarium poae (Peck) Wollenw.

Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg

       (syns. Gibberella fujikuroi (Sawada) Ito, mating population D; Gibberella fujikuroi var.

       intermedia Kuhlman; Gibberella intermedia (Kuhlman) Samuels,

       Nirenberg & Seifert)

Fusarium sporotrichioides Sherb.

Fusarium subglutinans (Wollenw. & Reinking) P. E. Nelson, Toussoun & Marasas

       (syns. Gibberella fujikuroi (Sawada) Ito, mating population E; Gibberella subglutinans

       (E. T. Edwards) P. E. Nelson, Toussoun & Marasas)

Fusarium temperatum Scaufl. & Munaut

Fusarium tricinctum (Corda) Sacc.

Fusarium verticillioides (Sacc.) Nirenberg

       (syns. Fusarium moniliforme J. Sheld.; Gibberella fujikuroi (Sawada) Ito, mating

       population A; Gibberella moniliformis Wineland)

Gibberella ear rot or red ear rot

Fusarium boothii O’Donnell et al.

Fusarium culmorum (Wm. G. Sm.) Sacc.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Fusarium meridionale T. Aoki et al.

Gray ear rot

Botryosphaeria zeae (G. L. Stout) Arx & E. Müll.

       (syns. Macrophoma zeae Tehon & E. Y. Daniels; Physalospora zeae G. L. Stout)

Nigrospora ear and cob rot

Nigrospora oryzae (Berk. & Broome) Petch

       (syns. Basisporium gallarum Molliard; Khuskia oryzae H. J. Huds.)

Penicillium ear rot and blue eye

Penicillium spp.

Penicillium chrysogenum Thom

Penicillium cyclopium Westling

Penicillium expansum Link

       (syn. Penicillium glaucum Link)

Penicillium funiculosum Thom

Penicillium oxalicum Currie & Thom

Penicillium verrucosum Dierckx

Penicillium viridicatum Westling

Rhizoctonia ear rot

Waitea circinata Warcup & Talbot

       (syn. Rhizoctonia zeae Voorhees)

Rhizopus ear rot

Rhizopus stolonifer (Ehrenb.:Fr.) Vuill.

Trichoderma ear rot

Trichoderma viride Pers.:Fr.

Ergot

Claviceps gigantea S. F. Fuentes, Isla, Ullstrup & A. E. Rodr.

Foliar Diseases

Alternaria leaf spot

Alternaria alternata (Fr.:Fr.) Keissl.

Anthracnose leaf blight

Colletotrichum graminicola (Ces.) G. W. Wilson

       (syn. Glomerella graminicola D. J. Politis)

Ascochyta leaf spot

Ascochyta maydis G. L. Stout

Ascochyta zeae G. L. Stout

Ascochyta zeina Sacc.

Curvularia leaf spot

Curvularia spp.

Curvularia aeria (Bat., J. A. Lima & C. T. Vasconc.) Tsuda

       (syn. Curvularia lunata (Wakker) Boedijn var. aeria (Bat., J. A. Lima & C. T. Vasconc.)

       M. B. Ellis)

Didymella leaf spot

Didymella exitialis (Morini) E. Müll.

Diplodia (Stenocarpella) leaf spot

Stenocarpella maydis (Berk.) B. Sutton

       (syns. Diplodia maydis (Berk.) Sacc.; Diplodia zeae Lév.)

Diplodia (Stenocarpella) leaf streak

Stenocarpella macrospora (Earle) B. Sutton

       (syns. Diplodia macrospora Earle; Stenocarpella zeae Syd. & P. Syd.)

Eyespot

Kabatiella zeae Narita & Y. Hirats.

       (syn. Aureobasidium zeae (Narita & Y. Hirats.) Dingley)

Fusarium leaf scorch

Fusarium verticillioides (Sacc.) Nirenberg

       (syns. Fusarium moniliforme J. Sheld.; Gibberella fujikuroi (Sawada) Ito,

       mating population A; Gibberella moniliformis Wineland)

Gray leaf spot

Cercospora spp.

Cercospora zeae-maydis Tehon & E. Y. Daniels

Cercospora zeina Crous & U. Braun

Hyalothyridium leaf spot

Astromella spp.

Hyalothyridium maydis Latterell & A. E. Rossi

Leptosphaerulina australis McAlpine

Leptosphaeria leaf spot

Paraphaeosphaeria michotii> (Westend.) O. E. Erikss.

       (syn. Leptosphaeria zeae G. L. Stout)

Phaeosphaeria variiseptata (G. L. Stout) Shoemaker & C. E. Babc.

       (syn. Leptosphaeria variiseptata G. L. Stout)

Northern corn leaf blight

Exserohilum turcicum (Pass.) K. J. Leonard & Suggs

       (syns. Bipolaris turcica (Pass.) Shoemaker; Drechslera turcica (Pass.) Subram. &

       P. C. Jain; Helminthosporium turcicum Pass.; Setosphaeria turcica (Luttr.)

       K. J. Leonard & Suggs; Trichometasphaeria turcica Luttr.)

Northern corn leaf spot

Bipolaris zeicola (G. L. Stout) Shoemaker

       (syns. Cochliobolus carbonum R. R. Nelson; Drechslera zeicola (G. L. Stout) Subram.

       & P. C. Jain; Helminthosporium carbonum Ullstrup)

Phaeosphaeria leaf spot

Phaeosphaeria maydis (Henn) Rane, Payak & Renfro

Phoma sp.

Physoderma brown spot

Physoderma maydis (Miyabe) Miyabe

       (syn. Physoderma zeae-maydis F. J. F. Shaw)

Rhizoctonia banded leaf and sheath blight

Rhizoctonia solani J. G. Kühn

       (syn. Thanatephorus cucumeris (A. B. Frank) Donk)

Rostratum leaf spot

Exserohilum rostratum (Drechsler) K. J. Leonard & Suggs

       (syns. Bipolaris rostrata (Drechsler) Shoemaker; Drechslera rostrata (Drechsler) M. J.

       Richardson & E. M. Fraser; Exserohilum halodes (Drechsler) K. J. Leonard &

       Suggs; Helminthosporium rostratum Drechsler; Setosphaeria rostrata K. J. Leonard)

Selenophoma leaf spot

Selenophoma spp.

Septoria leaf blotch

Septoria spp.

Southern corn leaf blight

Bipolaris maydis (Y. Nisik. & C. Miyake) Shoemaker

       (syns. Cochliobolus heterostrophus (Drechsler) Drechsler; Drechslera maydis (Y. Nisik.

       & C. Miyake) Subram. & P. C. Jain; Helminthosporium maydis Y. Nisik. C. Miyake;

       & Ophiobolus heterostrophus Drechsler)

Tar spot complex

Coniothyrium phyllachorae Maubl.

Monographella maydis E. Müll. & Samuels

Phyllachora maydis Maubl.

Yellow leaf blight

Didymella maydis (Arny & R. R. Nelson) Qian Chen & O. Cai

       (syn. Phyllosticta maydis Arny & R. R. Nelson)

Zonate leaf spot

Microdochium sorghi (D. C. Bain & Edgerton ex Deighton) U. Braun

       (syn. Gloeocercospora sorghi D. C. Bain & Edgerton ex Deighton)

Fungal Stalk Rots

Anthracnose stalk rot

Colletotrichum graminicola (Ces.) G. W. Wilson

       (syn. Glomerella graminicola D. J. Politis)

Black bundle disease

Sarocladium strictum (W. Gams) Summerb.

       (syn. Cephalosporium acremonium Corda)

Charcoal rot

Macrophomina phaseolina (Tassi) Goid.

       (syns. Botryodiplodia phaseoli (Maubl.) Thirum.; Macrophomina phaseoli (Maubl.)

       S. F. Ashby; Sclerotium bataticola Taubenh.)

Diplodia (Stenocarpella) stalk rot

Stenocarpella maydis (Berk.) B. Sutton

       (syns. Diplodia maydis (Berk.) Sacc.; Diplodia zeae Lév.)

Fusarium stalk rot

Fusarium spp.

Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg

       (syns. Gibberella fujikuroi (Sawada) Ito, mating population D; Gibberella

       intermedia (Kuhlman) Samuels, Nirenberg & Seifert)

Fusarium subglutinans (Wollenw. & Reinking) P. E. Nelson, Toussoun & Marasas

       (syns. Gibberella fujikuroi (Sawada) Ito, mating population E; Gibberella subglutinans (

       E. T. Edwards) P. E. Nelson, Toussoun & Marasas)

Fusarium temperatum Scaufl. & Munaut

Fusarium verticillioides (Sacc.) Nirenberg

       (syns. Fusarium moniliforme J. Sheld.; Gibberella fujikuroi (Sawada) Ito, mating

       population A; Gibberella moniliformis Wineland)

Gibberella stalk rot

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Nigrospora stalk rot

Nigrospora oryzae (Berk. & Broome) Petch

Other stalk rot

Phaeocytostroma ambiguum (Mont.) Petr.

       (syn. Phaeocytosporella zeae G. L. Stout)

Pythium stalk rot

Pythium aphanidermatum (Edson) Fitzp.

       (syn. Pythium butleri Subram.)

Red root rot

Setophoma terrestris (H. N. Hansen) Gruyter, Aveskamp & Verkley

       (syns. Phoma terrestris H. N. Hansen; Pyrenochaeta terrestris (H. N. Hansen)

       Gorenz, J. C. Walker & Larson)

Late Wilt

Magnaporthiopsis maydis (Samra, Sabet & Hing.) Klaubauf, Lebrun & Crous

       (syns. Cephalosporium maydis Samra, Sabet & Hing.; Harpophora maydis (Samra,

       Sabet & Hing.) W. Gams)

Mycotoxins and Mycotoxicoses

Aflatoxins

Aspergillus spp.

Aspergillus flavus Link:Fr.

Aspergillus parasiticus Speare

Deoxynivalenol and other trichothecenes

Fusarium spp.

Fusarium cerealis (Cooke) Sacc.

       (syn. Fusarium crookwellense L. W. Burgess, P. E. Nelson & Toussoun)

Fusarium culmorum (Wm. G. Sm.) Sacc.

Fusarium equiseti (Corda) Sacc.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Fusarium poae (Peck) Wollenw.

Fusarium sporotrichioides Sherb.

Diplodiatoxin

Stenocarpella maydis (Berk.) B. Sutton

       (syns. Diplodia maydis (Berk.) Sacc.; Diplodia zeae Lév.)

Fumonisins

Fusarium spp.

Fusarium proliferatum (Matsush.) Gerlach & Nirenberg

       (syn. Gibberella intermedia (Kuhlman) Samuels, Nirenberg & Seifert)

Fusarium verticillioides (Sacc.) Nirenberg

       (syns. Fusarium moniliforme J. Sheld.; Gibberella moniliformis Wineland)

Ochratoxins

Aspergillus spp.

Aspergillus alutaceus Berk. & M. A. Curtis var. alutaceus Berk. & M. A. Curtis

       (syn. Aspergillus ochraceus G. Wilh.)

Penicillium spp.

Penicillium verrucosum Dierckx

Other mycotoxins

Penicillium spp.

Aspergillus flavus Link:Fr.

Aspergillus parasiticus Speare

Fusarium proliferatum (Matsush.) Gerlach & Nirenberg

       (syn. Gibberella intermedia (Kuhlman) Samuels, Nirenberg & Seifert)

Fusarium subglutinans (Wollenw. & Reinking) P. E. Nelson, Toussoun & Marasas

       (syns. Gibberella fujikuroi (Sawada) Ito; Gibberella subglutinans (E. T. Edwards)

       P. E. Nelson, Toussoun & Marasas)

Zearalenone

Fusarium cerealis (Cooke) Sacc.

       (syn. Fusarium crookwellense L. W. Burgess, P. E. Nelson & Toussoun)

Fusarium culmorum (Wm. G. Sm.) Sacc.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Root Rots

Fusarium root rot

Fusarium spp.

Fusarium acuminatum Ellis & Everh.

Fusarium equiseti (Corda) Sacc.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Fusarium oxysporum Schltdl.:Fr.

Fusarium proliferatum (Matsush.) Gerlach & Nirenberg

Fusarium solani (Mart.) Sacc.

Fusarium subglutinans (Wollenw. & Reinking) P. E. Nelson, Toussoun & Marasas

Fusarium verticillioides (Sacc.) Nirenberg

Pythium root rot (and feeder root necrosis)

Phytopythium helicoides (Drechsler) Abad et al.

       (syn. Pythium helicoides Drechsler)

Phytopythium vexans (de Bary) Abad et al.

       (syn. Pythium vexans de Bary)

Pythium spp.

Pythium acanthicum Drechsler

Pythium adhaerens Sparrow

Pythium angustatum Sparrow

Pythium aphanidermatum (Edson) Fitzp.

Pythium arrhenomanes Drechsler

Pythium graminicola Subram.

Pythium irregulare Buisman

Pythium lutarium Ali-Shtayeh

Pythium paroecandrum Drechsler

Pythium pulchrum Minden

Pythium rostratum E. J. Butler

Pythium splendens Hans Braun

Pythium sylvaticum W. A. Campb. & F. F. Hendrix

Pythium tardicrescens Vanterp.

Pythium torulosum Coker & P. Patt.

Pythium ultimum Trow

Red root rot

Setophoma terrestris (H. N. Hansen) Gruyter, Aveskamp & Verkley

       (syns. Phoma terrestris H. N. Hansen; Pyrenochaeta terrestris (H. N. Hansen) Gorenz,

       J. C. Walker & Larson)

Rhizoctonia crown and brace root rot

Rhizoctonia solani J. G. Kühn

       (syn. Thanatephorus cucumeris (A. B. Frank) Donk)

Rusts

Common rust

Puccinia sorghi Schwein.

Southern rust

Puccinia polysora Underw.

Tropical rust

Phakopsora zeae (Mains) Buriticá

       (syns. Angiopsora zeae Mains; Physopella zeae (Mains) Cummins & Ramachar)

Seed Rots and Seedling Blights (Damping-Off)

Alternaria spp.

Aspergillus spp.

Aspergillus flavus Link:Fr.

Aspergillus tamarii Kita

Bipolaris spp.

Fusarium spp.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Fusarium oxysporum Schltdl.:Fr.

Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg

Fusarium solani (Mart.) Sacc.

Fusarium subglutinans (Wollenw. & Reinking) P. E. Nelson, Toussoun & Marasas

Fusarium temperatum Scaufl. & Munaut

Fusarium verticillioides (Sacc.) Nirenberg

Nigrospora spp.

Penicillium spp.

Penicillium oxalicum Currie & Thom

Phytopythium vexans (de Bary) Abad et al.

       (syn. Pythium vexans de Bary)

Pythium spp.

Pythium debaryanum R. Hesse

Pythium irregulare Buisman

Pythium paroecandrum Drechsler

Pythium rostratum E. J. Butler

Pythium ultimum Trow

Rhizoctonia spp.

Rhizoctonia solani J. G. Kühn

Rhizopus spp.

Stenocarpella maydis(Berk.) B. Sutton

Trichoderma spp.

Smuts

Common smut

Ustilago maydis (DC.) Corda

       (syn. Ustilago zeae (Beckm.) Unger)

False smut

Ustilaginoidea virens (Cooke) Takah.

       (syn. Ustilaginoidea oryzae (Pat.) Bref.)

Head smut

Sporisorium reilianum (J. G. Kühn Langdon & Full.

       (syns. Sorosporium reilianum (J. G. Kühn) McAlpine; Sphacelotheca reiliana

       (J. G. Kühn) G. P. Clinton; Sporisorium holci-sorghi (Rivolta) Vánky; Sporisorium

       reilianum (J. G. Kühn) Langdon & Full. f. sp. zeae (J. G. Kühn)

       Langdon & Full.; Ustilago reiliana J. G. Kühn)

Storage Molds

Alternaria spp.

Aspergillus spp.

Aspergillus candidus Link:Fr.

Aspergillus flavus Link:Fr.

Aspergillus fumigatus Fresen.

Aspergillus glaucus (L.) Link:Fr.

Aspergillus ochraceus G. Wilh.

Aspergillus restrictus G. Sm.

Aspergillus versicolor (Vuill.) Tirab.

Cladosporium spp.

Fusarium spp.

Fusarium graminearum Schwabe

       (syn. Gibberella zeae (Schwein.) Petch)

Fusarium verticillioides (Sacc.) Nirenberg

Mucor spp.

Nigrospora oryzae (Berk. & Broome) Petch

Penicillium spp.

Penicillium brevi-compactum Dierckx

Penicillium chrysogenum Thom

Penicillium citrinum Thom

Penicillium cyclopium Westling

Penicillium funiculosum Thom

Penicillium oxalicum Currie & Thom

Penicillium viridicatum Westling

Rhizopus spp.

Rhizopus stolonifer (Ehrenb.:Fr.) Vuill.

Trichothecium roseum (Pers.) Link

MOLLICUTE DISEASES

Corn stunt

Spiroplasma kunkelii Whitcomb et al.

Maize bushy stunt

Maize bushy stunt phytoplasma: ‘Candidatus Phytoplasma asteris,’ 16S rDNA group I-B

Maize redness

Stolbur phytoplasma: ‘Candidatus Phytoplasma solani,’ 16S rDNA group XII-A

NEMATODES (PARASITIC)

Awl nematode

Dolichodorus heterocephalus Cobb

Cyst nematodes

Corn cyst nematode

       Heterodera zeae Koshy, Swarup & Sethi

Mexican corn cyst nematode

       Punctodera chalcoensis Stone, Sosa Moss & Mulvey

Goosegrass cyst nematode

       Vittatidera zeaphila Bernard et al.

Dagger nematodes

Xiphinema americanum Cobb

Xiphinema chambersi Thorne

Xiphinema rivesi Dalmasso

Lance nematodes

Hoplolaimus columbus Sher

Hoplolaimus galeatus (Cobb) Thorne

Needle nematode

Longidorus breviannulatus Norton & Hoffmann

Ring nematodes

Criconemella ornata (Raski) Luc & Raski

Criconemella sphaerocephala (Taylor) Luc & Raski

Root-knot nematodes

Meloidogyne arenaria (Neal) Chitwood

Meloidogyne chitwoodi Golden et al.

Meloidogyne hapla Chitwood

Meloidogyne incognita (Kofoid & White) Chitwood

Meloidogyne javanica (Treub) Chitwood

Root lesion nematodes

Pratylenchus spp.

Pratylenchus brachyurus (Godfrey) Filipjev & Schuurmans-Stekhoven

Pratylenchus hexincisus Taylor & Jenkins

Pratylenchus neglectus (Rensch) Filipjev & Schuurmans-Stekhoven

Pratylenchus penetrans (Cobb) Chitwood & Oteifa

Pratylenchus scribneri Steiner

Pratylenchus zeae Graham

Spiral nematodes

Helicotylenchus digonicus Perry

Helicotylenchus dihystera (Cobb) Sher

Helicotylenchus pseudorobustus (Steiner) Golden

Scutellonema brachyurum (Steiner) Andrássy

Sting nematodes

Belonolaimus spp.

Belonolaimus longicaudatus Rau

Stubby-root nematodes

Paratrichodorus minor (Colbran) Siddiqi

       (syns. Paratrichodorus christiei (Allen) Siddiqi; Trichodorus christiei Allen; Trichodorus minor Colbran; Trichodorus obesus Razjivin & Penton)

Paratrichodorus porosus (Allen) Siddiqi

Stunt nematodes

Tylenchorhynchus claytoni Steiner

Tylenchorhynchus maximus Allen

NONINFECTIOUS OR ABIOTIC DISEASES AND DAMAGE

Air Pollutants

Chlorine

Fluorides

Ozone

Peroxyacetyl nitrate (PAN)

Sulfur dioxide

Environmental Factors

Drought damage

Excess moisture damage

Damage intensified by warmer weather; plants without nodal roots

Frost damage

Most severe in organic soil and low-lying areas; increases with density of bacterial cells

High-temperature scalding

Usually in association with low soil moisture and hot, dry winds

Low-temperature sunscald and cold banding

Happens with cool, clear, dewy nights followed by clear, sunny mornings

Wind damage

Abrasions, breakage, lodging, pinching, shredding

Greensnap

Herbicide Injury

Excess rate of use; use of herbicides to which corn has a low tolerance; carryover or drift

Nutrient Deficiencies

Boron

Rare; drought; high-pH soil; and sandy, low-organic-matter soil

Calcium

Rare; very-low-pH soil; soil high in potassium and magnesium

Copper

Rare; high-organic-matter soil

Iron

Rare; high-pH soil; wet, compacted, poorly aerated soil; cool weather

Magnesium

Strongly acidic, sandy soil in regions of moderate to high rainfall; high-potassium soil; and soil treated with limestone low in magnesium

Manganese

High-pH soil; peat, muck, and sandy soils high in organic matter

Molybdenum

Rare; low-pH soil; heavily weathered soil

Nitrogen

Cold, wet, or flooded soil; drought (especially after midseason); sandy, low-organic-matter soil; heavy, leaching rains; standing water in warm weather; intensive row cropping

Phosphorus

Cool, wet soil

Potassium

Sandy, organic, wet, or compacted, weathered soil; potassium removal by preceding crops

Sulfur

Acidic, sandy, low-organic-matter soil; cold, wet soil

Zinc

High-phosphorus soil or fertilizer; high-pH soil; cool, wet soil; low-organic-matter soil (exposed subsoil)

Nutrient Toxicities

Anhydrous ammonia or aqua-ammonia damage

Ammonia (NH3) release from fertilizing practices; sandy, dry, compact, and low-organic-matter soil; uneven soil surface; deep planting; shallow placement of NH3

Fertilizer burn

Nutrient toxicity (excessive soluble nitrogen, potassium, or boron fertilizers); sandy soil; dry weather; high-salt-index fertilizer

Other nutrient excesses

Accumulation of aluminum oxides, iron oxides, nickel, and chromium

Other Abnormalities

Barren stalks

Low fertility; drought; dense plant populations; aphid or herbicide damage

Blunt ear syndrome

Temperature stress (brief cold shock); surfactants application

Branched ear

Undetermined

Buggy-whip

Some herbicides (e.g., 2,4-D); warm growing conditions; genetic connection

Exposed ear tips

Extreme drought during kernel set followed by abundant rainfall and good growing conditions

Genetic stripe, leaf spots, and flecks

Genetic abnormality

Kernel red streak

Associated with a toxin produced by a strain of the wheat curl mite, Eriophyes tulipae

Popped kernel

Inherited; irregular rainfall, particularly with very hot, dry conditions

Purple leaf sheath

Genetic connection; particulate matter lodged between the stalk and the leaf sheath for saprophytic fungi and bacteria to grow on

Red leaf

Accumulation of sugars and other photosynthetic products

Red stalk

Broken midrib

Rootless corn syndrome

Hot, dry surface soil; excessive rainfall; or strong, abrasive winds; shallow planting; compact soil; loose or cloddy soil

Silk-cut

Inherited; exact cause unknown

Soil crusting and leafing out underground

Wet soil; intensive tillage; heavy rains after planting; fine-textured soil

Tassel ear (floral abnormality)

Plants injured by hail, frost, flooding, herbicides, or mechanical damage

Tassel tip (floral abnormality)

Genetic connection

PARASITIC PLANT

Witchweed

Striga spp.

Striga asiatica (L.) Kuntze

       (syn. Striga lutea Lour.)

Striga hermonthica (Del.) Benth.

VIRAL DISEASES

Barley yellow dwarf

Genus Luteovirus:

       Barley yellow dwarf virus-MAV, strain (BYDV-MAV)

       Barley yellow dwarf virus-PAV, strain (BYDV-PAV)

Genus Polerovirus:

       Cereal yellow dwarf virus-GPV, strain (CYDV-GPV)

       Cereal yellow dwarf virus-RPV, strain (CYDV-RPV)

Brome mosaic

Genus Bromovirus, Brome mosaic virus (BMV)

Cereal chlorotic mottle

Genus Nucleorhabdovirus, Cereal chlorotic mottle virus (CCMV)

Cucumber mosaic

Genus Cucumovirus, Cucumber mosaic virus (CMV)

High Plains disease

Genus Emaravirus, Wheat mosaic virus (WMoV)

       (syns. High Plains virus (HPV), Maize red stripe virus (MRStV))

Maize chlorotic dwarf

Genus Waikavirus, Maize chlorotic dwarf virus (MCDV)

Maize chlorotic mottle

Genus Machlomovirus, Maize chlorotic mottle virus (MCMV)

Maize dwarf mosaic

Genus Potyvirus:

       Johnsongrass mosaic virus (JGMV)

       Maize dwarf mosaic virus (MDMV)

       Pennisetum mosaic virus (PenMV)

       Sorghum mosaic virus (SrMV)

       Sugarcane mosaic virus (SCMV)

       Zea mosaic virus (ZeMV)

Genus Tritimovirus, Wheat streak mosaic virus (WSMV)

Maize fine streak

Genus Nucleorhabdovirus; Maize fine streak virus (MFSV)

Maize leaf fleck

Genus has not been assigned, Maize leaf fleck virus (MLFV)

Maize lethal necrosis

Genus Machlomovirus, Maize chlorotic mottle virus (MCMV) combined with Potyviridae infection, e.g., Maize dwarf mosaic virus (MDMV) (Potyvirus); Sugarcane mosaic virus (SCMV) (Potyvirus); Wheat streak mosaic virus (WSMV) (Tritimovirus)

Maize mosaic

Genus Nucleorhabdovirus, Maize mosaic virus (MMV)

Maize necrotic streak

Genus Zeavirus, Maize necrotic streak virus (MNeSV)

Maize rayado fino

Genus Marafivirus, Maize rayado fino virus (MRFV)

Maize rough dwarf

Genus Fijivirus:

       Maize rough dwarf virus (MRDV)

       Rice black streak dwarf virus (RBSDV)

Maize streak

Genus Mastrevirus, Maize streak virus (MSV)

Maize stripe

Genus Tenuivirus, Maize stripe virus (MStV)

Maize white line mosaic

Genus Aureusvirus, Maize white line mosaic virus (MWLMV)

Mal de Rio Cuarto

Genus Fijivirus, Mal de Rio Cuarto virus (MRCV)

Rice stripe

Genus Tenuivirus, Rice stripe virus (RSV)

Wheat streak mosaic

Genus Tritimovirus, Wheat streak mosaic virus (WSMV)