Cause Alkali yellows is caused by strongly alkaline soil, which can make iron or manganese unavailable to plants. Although soil pH may be the main problem, iron could be lacking in the soil or in a form unavailable to plants. A frequent problem sent into the OSU Plant Clinic from areas east of the Cascade Range.
Symptoms Younger leaves show yellowing or lack of green chlorophyll between the veins. Veins tend to remain green in comparison. Interveinal areas may become slightly necrotic. New leaves continue to be small and may look white or bleached. Root volume is restricted and roots may be yellowish. No symptoms occur on flowers or fruit. Symptoms are similar for either iron or manganese deficiency.
Cultural control
- Adjust soil pH to 6.2, which is optimal for strawberry.
- Check plant's proximity to newly poured concrete. New concrete leaches lime into the surrounding soil, raising the pH.
- Use iron chelate, either as a soil treatment or by foliar feeding, to quickly help chlorotic plants. Read and follow all label instructions.
Reference Zaiter, H. Z., Saad, I. and Nimah, M. 1993. Yield of iron-sprayed and non-sprayed strawberry cultivars grown on high pH calcareous soil. Communications in soil science and plant analysis, 24:1421-1436.