Rhizomania
(click image to enlarge) Symptoms:
• Necrotic, yellow veins are rarely seen
• Common are general chlorosis leading to bright, fluorescent yellow leaf color ("blinker")
• Leaves are elongated and erected
• Infection of younger plants can lead to stunting
Epidemiology:
• Viral disease caused by Beet necrotic yellow vein virus
• Transmitted by ubiquitous soil fungus Polymyxa betae
• Fungus is favored by near-saturated soil conditions
• Soil temperatures from 59-83° F
Control:
• Resistant varieties
• Irrigation management
• No fungicides are available for the control of P. betae