reference

List of Plant Disease Resistance Codes

A plain-language key to the disease and pest resistance codes used in variety descriptions, with the pathogen and crop for each code.
By Hensley’s Seed Co.
Disease Resistance Codes

Plant Disease Resistance Codes

An alphabetical list of disease code acronyms used on our website and in our catalog.

Key: HR = high resistance; IR = intermediate resistance
  • A — anthracnose; cause: fungal
    • Colletotrichum lindemuthianum (on bean)
    • C. orbiculare (on cucurbits, watermelon)
  • AB — Alternaria blight; cause: fungal Alternaria dauci (on carrot) [tomato version: see EB ]
  • ALS — angular leaf spot; cause: bacterial Pseudomonas syringae pv. lachrymans (on cucumber)
  • AS — Alternaria stem canker; cause: fungal Alternaria alternata f. sp. lycopersici (on tomato)
  • B — bacterial wilt; cause: bacterial
    • Erwinia tracheiphila (on cucumber)
    • Ralstonia solanacearum (on tomato)
  • BB — bacterial blight; cause: bacterial Xanthomonas hortorum pv. carotae (on carrot)
  • BBS — bacterial brown spot; cause: bacterial Pseudomonas syringae pv. syringae (on bean)
  • BLS — bacterial leaf spot Xanthomonas campestris pv. vesicatoria (on pepper)
  • BMV — bean common mosaic virus; crop: bean
  • BO — Botrytis leaf blight and neck rot of onion; cause: fungal Botrytis allii (on onion)
  • BR — black rot; cause: bacterial Xanthomonas campestris pv. campestris (on brassicas)
  • BRoot — black root; cause: oomycete (water mold) Aphanomyces raphani (on radish)
  • BS — black speck; cause: fungal Rhizoctonia spp.
  • C — Cercospora blight; cause: fungal Cercospora carotae (on carrot)
  • CA — cotton aphid; type: insect pest Aphis gossypii (on melon)
  • CMV — cucumber mosaic virus; crops: cucurbits
  • CR — clubroot; cause: protist (traditionally grouped with fungi) Plasmodiophora brassicae (on cabbage)
  • CRR — corky root rot; cause: fungal Pyrenochaeta lycopersici (on tomato)
  • CS — cavity spot; cause: oomycete (water mold) Pythium spp. (on carrot)
  • CTM — beet curly top virus; crop: beet
  • Cv — Cladosporium leaf spot; cause: fungal Cladosporium variabile (on spinach)
  • CVYV — cucumber vein yellowing virus; crops: cucumber
  • DM — downy mildew; cause: oomycete (water mold)
    • Bremia lactucae (on lettuce)
    • Hyaloperonospora brassicae (on radish)
    • H. parasitica (on arugula)
    • H. brassicae (on broccoli, cabbage, chinese cabbage)
    • Peronospora belbahrii (on basil)
    • P. destructor (on onion)
    • P. effusa (on spinach)
    • P. viciae (on pea)
    • Pseudoperonospora cubensis (on cucumber)
  • EB — early blight (Alternaria blight); cause: fungal Alternaria solani (on tomato)
  • F — Fusarium wilt; cause: fungal
    • Fusarium oxysporum f. sp. basilici (on basil)
    • F. oxysporum f. sp. lycopersici (on tomato)
    • F. oxysporum f. sp. melonis (on melon)
    • F. oxysporum f. sp. niveum (on watermelon)
    • F. oxysporum f. sp. pisi (on pea)
  • FBR — Fusarium basal rot; cause: fungal Fusarium oxysporum f. sp. cepae (on onion)
  • FLB — foliar late blight; cause: oomycete (water mold) Phytophthora infestans (on potato)
  • FOR — Fusarium crown and root rot; cause: fungal Fusarium oxysporum f. sp. radicis–lycopersici (on tomato)
  • FY — Fusarium yellows; cause: fungal
    • Fusarium oxysporum f. sp. conglutinans (on brassicas)
    • F. oxysporum f. sp. raphani (on radish)
  • GLS — gray leaf spot; cause: fungal Stemphylium solani (on tomato)
  • HB — halo blight; cause: bacterial Pseudomonas savastanoi pv. phaseolicola (on bean)
  • LB — late blight; cause: oomycete (water mold) Phytophthora infestans (on tomato)
  • LM — leaf mold; cause: fungal Cladosporium fulvum also called Fulvia fulva (on tomato)
  • LMV — lettuce mosaic virus; crops: lettuce
  • MDMV | — maize dwarf mosaic virus; crop: corn
  • MT0-10 | Seed lot tested for lettuce mosaic virus with none detected in a sample of at least 10,000 seeds.
  • MT0-30 | Seed lot tested for lettuce mosaic virus with none detected in a sample of at least 30,000 seeds.
  • N — root-knot nematodes; cause: nematode Meloidogyne arenaria, M. incognita, M. javanica (on tomato)
  • NCLB — northern corn leaf blight; cause: fungal Exserohilum turcicum (on corn)
  • Nr — lettuce leaf aphid; type: insect pest Nasonovia ribisnigri (on lettuce)
  • Pb — lettuce root aphid; type: insect pest Pemphigus bursarius (on lettuce)
  • PC — Phytophthora blight; cause: oomycete (water mold) Phytophthora capsici (on pepper)
  • PEMV — pea enation mosaic virus; crops: pea
  • PLR — pea leaf roll virus; crops: pea
  • PM — powdery mildew; cause: fungal
    • Erysiphe heraclei or Leveillula taurica (on carrot)
    • Erysiphe pisi (on peas)
    • E. polygoni (on beans)
    • Oidium neolycopersici (on tomato)
    • Podosphaera xanthii (on cucurbits, watermelon)
  • PMV — pepper mottle virus Potyvirus (on pepper)
  • PR — pink root; cause: fungal Phoma terrestris (on onion)
  • PRSV — papaya ringspot virus; crops: cucurbits
  • PU — purple blotch; cause: fungal Alternaria porri (on leek)
  • PVY | Potato Virus Y (Pepper)
  • R — common rust; cause: fungal
    • Puccinia allii (on leek)
    • P. asparagi (on asparagus)
    • P. sorghi (on corn)
    • Uromyces appendiculatus (on bean)
  • Rs — corky root; cause: bacterial Rhizomonas (now Sphingomonas) suberifaciens (on lettuce)
  • RZ — Rhizoctonia or black scurf; cause: fungal
    • Rhizoctonia solani (on potato)
    • Rhizoctonia solani (on radish)
  • S — scab; cause:
    • bacterial: Streptomyces scabies and other S. spp. (on potato)
    • fungal: Cladosporium cucumerinum (on cucumber)
  • SCLB — southern corn leaf blight; cause: fungal Bipolaris maydis (on corn)
  • Sv — Stemphylium leaf spot; cause: fungal Stemphylium vesicarium (on spinach)
  • SW — Stewart's wilt; cause: bacterial Pantoea stewartii (on corn)
  • TBSV — tomato bushy stunt virus; crops: lettuce dieback complex [lettuce]
  • TEV — tobacco etch virus; crops: pepper
  • TLB — tuber late blight Phytophthora infestans (on potato)
  • TM | Tobamovirus (Pepper)
  • TMV — tobacco mosaic virus; crops: nightshade family
  • ToANV — tomato apex necrosis virus; crops: tomato
  • ToMV — tomato mosaic virus; crops: tomato, pepper
  • TSP — target spot; cause: fungal Corynespora cassiicola (on cucumber)
  • TSWV — tomato spotted wilt virus; crops: tomato
  • TYLCV — tomato yellow leaf curl virus; crops: tomato
  • V — Verticillium wilt; cause: fungal Verticillium albo–atrum and other V. spp. (on potato, tomato)
  • WMV — watermelon mosaic virus; crops: cucurbits
  • WR — white rust; cause: oomycete (water mold)
    • Albugo occidentalis (on spinach)
    • Albugo candida (on cabbage)
  • WT — white tip; cause: oomycete (water mold) Phytophthora porri (on leek)
  • ZYMV — zucchini yellow mosaic virus; crops: cucurbits
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