Nutritional disorder – zinc (Zn) deficiency
Younger leaves initially develop a yellow interveinal chlorosis in the interior of the leaf, while the outside margin remains green. This produces a halo effect. Leaf blades are typically narrower and elongated. With severe deficiencies the interveinal areas can develop necrosis.
Fruit size is normal, but the number produces is less.
Iron, manganese, and molybdenum deficiencies may produced similar symptoms.
Because symptoms can occur due to many possible causes, it is important to determine the actual cause. Tissue testing will help identify any nutritional disorders. Nutrient deficiencies usually take weeks to develop.
Take a soil sample to determine if nutrient levels are inadequate. Submit a leaf sample for nutrient analysis. The sufficiency range for zinc in strawberries is between 15 and 60 ppm. Some references recommend a narrower range of 20 to 40 ppm or 30 to 100 ppm. Values below 15 ppm are considered deficient and above 80 ppm 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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