Phoma Leaf Spot

(click image to enlarge) Symptoms:
• Lesions are light brown; round to oval (1-2 cm) with dark concentric rings
• Dark colored fungal fruiting structures within the lesion or concentric rings
• Disease intensity is usually greatest on lower leaves

Epidemiology:
• Favored by wet conditions
• Temperatures between 59-90° F
• Of little economic importance
• Seed borne
• Can survive in infected crop or lambsquarter residues for up to 26 months

Control:
• Control overhead irrigation to minimize leaf wetness
• Increase air circulation by reducing stand