Wet - At or above baseline

Field Capacity/ Runoff. Not common in prunes

Low/Mild Stress 0 to 6 bars below baseline

Very low stress levels. May occur in March and April. Indicates soil moisture is not limiting. If low crop stress is sustained through the growing season, higher incidence of disease and tree loss may occur (-6 to -8)

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Low to mild stress. Favors rapid shoot growth and fruit sizing in orchards when low to mild crop stress is sustained from April through mid-June (-8 to -12)

Mild/Moderate Stress -6 to 12 bars below baseline

Mild to moderate stress levels. Appropriate beginning in late June through early August. Rate of shoot growth may be slower, but rate of fruit sizing is unaffected. May help manage energy and irrigation costs 

Moderate/High Stress -12+ below baseline

Moderate to high stress levels. Rate of shoot growth slow or stops. Should be avoided until fruit sizing is complete d in early to mid-August. Once fruit sizing is completed, imposing moderate to high levels of stress by reducing irrigation about two weeks before harvest may increase sugar content in fruit and reduce moisture content or "dry-away" (-16 to -20)

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High to severe crop stress. More likely to occur in late August and early September, when irrigation is suspended for harvest. Extended periods of high to severe crop stress before harvest results in defoliation and exposure of limbs and fruit to sunburn.. May also negatively affect the condition of trees going into dormancy (-20 to -30)

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Severe crop stress. Extended periods of severe crop stress should be avoided (less than -30)

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