Pyrenochaeta lycopersici

Brown root rot, corky root rot


Pyrenochaeta lycopersici is a fungal plant pathogen, infecting tomatoes and aubergine. It causes brown root rot and corky root rot.

Life cycle and appearance of Brown root rot, corky root rot

Pyrenochaeta lycopersici survives in the soil and in buried tomato roots as microsclerotia. The microsclerotia germinate and produce mycelium that in turn infect the roots of tomato and other hosts. Several alternate hosts in outdoor cropping systems are known: pepper, melon, aubergine, squash, spinach and safflower. The disease develops between 8 and 32 °C, but the fungus prefers low temperatures. Therefore, optimal temperatures for disease development lie between 15 and 20 °C. Development reduces at temperatures above 20 °C. The fungus produces pycnidia containing conidiophores with conidia and microsclerotia.

Spread happens through dispersal of soil particles by farm equipment and cultivation practices. However, this fungus is a poor competitor against a balanced microbial population in soil.

How to prevent Brown root rot, corky root rot

Field crops:

  • Fumigate the soil
  • Practise crop rotation with non-host crops
  • Delay planting in the spring until soil temperatures are higher
  • Mound soil around the stem to promote adventitious root growth

Greenhouse crops:

  • Steam or fumigate the soil
  • Disinfect nutrient solutions


  • Choose resistant cultivars or graft on resistant rootstock
  • Avoid frequent irrigation. Remove and destroy affected plants

Prevent plant diseases by optimizing plant potential and crop resilience.