Blossom End Rot

Causal organism: Physiological disorder

Crops Affected: most commonly associated with fruiting vegetables like tomatoes, peppers, eggplant, however other fruiting vegetables may have BER develop (e.g. squash/pumpkins/melons, etc.)

Disease Cycle / Conditions Favouring Disease Development:

• Not caused by a pathogen
• Physiological disorder caused by a localized deficiency of calcium in the fruit
• Typically linked to growing conditions that result in uneven and/or interrupted uptake of calcium from the soil or growing medium into the plant
  • Hot/dry, drought conditions and/or fluctuations in water supply
  • Other factors can also influence incidence of BER
    • Rapid plant growth (unable to keep up with demand for calcium)
    • High soil nitrogen and magnesium levels (competition for uptake in the plant “pipeline”)
    • Saline soils (creates imbalance in the osmotic [H2O flow] pathway through membranes)
    • Root damage (plant unable to take up nutrients adequately)
    • High relative humidity (slows down the draw/flow of water through the plant from top to bottom)
  • Not necessarily related to the levels of calcium available in the soil, merely the ability of the plant to take up enough calcium to meet developing fruit needs

Symptoms:

• Often starts on younger fruit (1/3 developed), but symptoms may develop in any stage of fruit development
• Light brown patches appear at the blossom end of the fruit, or occasionally on the sides
  • Over time, patches darken and become sunken, as tissues die
  • Sunken areas can cover as much as half of the fruit
• Tissues may be infected by secondary pathogens, resulting in additional fruit rots

Management:

• Ensure that plants maintain a healthy, even growth and steady uptake of water
  • Irrigation will allow water availability to be more consistent
• Avoid root damage and encourage strong and deep root growth
  • Ensure that root development and health is maintained to ensure that the plant can take up calcium as needed
• Practices that promote moisture conservation in the soil (e.g. mulches) can be beneficial towards reducing BER
• If calcium levels are insufficient or in question, the application of calcium-rich fertilizers or amendments, or the application of foliar-applied calcium prior to symptom development can be effective

On the Canadian prairies, most soils were derived from calcium-rich parent materials, therefore deficiencies in soil calcium are unusual