Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Tomato blossom end rot (082)

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  • Worldwide distribution. On tomato, although eggplant, capsicum and watermelon are also affected. An important physiological problem.
  • It is not a disease. Occurs when fruits are green, and a third to half full size.
  • Light brown areas at the blossom end, becoming dark brown, dry, sunken. More common on first fruit.
  • Cause: too little calcium (Ca) in e.g., sandy soil; too little or too much water; low pH prevents Ca uptake; conditions too hot and dry; too much nitrogen in the soil.
  • Cultural control: ensure good drainage (raise beds); add organic matter; apply mulch; do not damage roots when cultivating; use windbreaks; do not use urea, ammonium types of fertilizer or 'raw' chicken manure; tolerant varieties.
Common Name

Blossom-end rot

Scientific Name

Blossom-end rot has a 'physiological' cause; it is due to a lack of calcium. It is not caused by insects, fungi, bacteria, or any other pathogens. It is not a disease.

AUTHORS Suzanne Neave & Grahame Jackson
Information from Blossom end rot (2018) Plant Disease Diagnostic Clinic, Plant Pathology and Plant-Microbe Biology Section, Cornell University College of Agriculture and Life Sciences. (; and from Growing vegetables: Managing blossom end-rot. University of New Hampshirre. ( Photo 2 Kohler F, et al. (1997) Diseases of cultivated crops in Pacific Island countries. South Pacific Commission. Pirie Printers Pty. Limited, Canberra, Australia.

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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