Nutritional disorder – sulfur (S) deficiency
Middle to upper leaves develop a light green coloration. Over time the leaves become more uniformly yellow in coloration. With severe deficiencies the pale yellow leaves can develop necrotic spotting due to sunburning.
The fruit can also be smaller in size, but have normal color.
Nitrogen deficiency can be confused with sulfur deficiency. In contrast, nitrogen deficiencies begin on the oldest leaves and work their way up the plant.
With the burning of coal atmospheric sulfur provides sufficient levels of the element to prevent deficiencies from occurring.
Sulfur deficiencies are rare. Tissue testing will help identify any nutritional disorders. Glyphosate spray drift will also result in leaf yellowing, but those symptoms tend to be on the new growth.
The pattern of how the symptoms develop will aid in diagnosis. Symptoms begin in the middle part of the plant and move upward. Submit a leaf sample for nutrient analysis. The sufficiency range for sulfur in strawberries vary by source. The widest recommended range is 0.25% to 0.8%, while 0.15 to 0.4% is listed by another reference and 0.4 to 0.6% by a third.
Values lower than 0.25 to 0.35% are considered deficient, while levels above 0.8% are considered excessive.
Take a soil and tissue test to determine nutrient levels. Make adjustments based on those test results and the lab’s recommendations.
Conduct a soil test prior to planting the crop to determine if pre-plant fertilizer applications are required. Fertilizer can also be injected to the crop during active growth. Recommendations vary by soil type and your location, so check with local resources for guidelines.
Funding was provided in part by the National Sustainable Agriculture Program: Sustainable Strawberry Initiative and the following sources.
A thank you is also expressed to Kube Pak of Allentown, New Jersey for donating strawberry plants.
Publication date: April 24, 2014
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