Early dying complex

Early dying complex: biology

Early dying occurs when potato plants fail to reach maturity due to infection by a complex of plant pathogens and/or conditions, including:

  • Verticillium dahlia
  • Verticillium ablo-atrum
  • Soft rot bacteria (Pectobacterium species (Erwinia))
  • Pathogenic nematodes
  • Black dot (Colletotrichum coccodes)
  • Nutrient deficiencies
As its name suggests, early dying is a complex issue. A combination of factors can cause the premature death of potato vines.

Early dying complex: damage description

Plants decline 4-6 weeks prior to normal maturity, and may appear stressed. Foliage shows degrees of chlorosis (yellowing) and necrosis (dead tissue), sometimes associated with wilting or dying of stems or leaflets. Individual vines may die and remain erect. Throughout an affected field, individual plants or groups of plants may show symptoms (Rowe & Powelson, 2002).

When early dying becomes severe during tuber bulking, tuber size and yield can be significantly impacted. Rowe & Powelson (2002) suggest that in the case of moderate disease, yield reduction can be 10-15%, and in severely diseased fields it can be as high as 30-50%.

Early dying complex: management

Varieties have different levels of susceptibility to early dying. The following have been identified:

  • Very Susceptible: Kennebec, Superior
  • Susceptible: Atlantic, Norland, Red Pontiac, Russet Norkotah, Shepody
  • Moderately Susceptible: Envol, Russet Burbank, Shepody
  • Moderately Resistant: Chieftain, Goldrush, Krantz, Umatilla
  • Resistant: Alturas, Ranger Russet
Certain crop management factors can impact early dying. Buy clean seed, avoid early irrigation, and try not to irrigate during early flowering/tuber initiation. As much as possible, avoid nutrient deficiencies and compaction. Limit cross contamination by cleaning soil from all machinery.

Crop rotation and disease control can be used as preventative disease management. Rotation and weed control will not eradicate Verticillium that is already present in fields.

Sources:
https://www.topcropmanager.com/inoculants/unravelling-potato-early-dying-complex-732
http://www.umanitoba.ca/faculties/afs/MAC_proceedings/2003/pdf/selvanathan_potato_complex.pdf