Iron Chlorosis

California grape shows interveinal yellowing of young leaves due to iron unavailability in high-pH soils. Iron deficiency chlorosis develops on alkaline soils. Acidify soil by adding sulfur or organic matter before planting. Use iron chelate as a foliar or soil treatment for quick recovery on affected plants.

Management depends on catching it early. Scout susceptible plants regularly and remove affected tissue before the pathogen can spread. Improve growing conditions by addressing drainage, spacing, and irrigation practices. For persistent or severe cases, contact your local Master Gardener program or Extension office for treatment options specific to your host plants.