Eventually, all leaves may become infected. Damage Description Yield loss due to powdery mildew will occur if the disease is allowed to go unchecked. The earlier the disease occurs during the season, the greater the loss. Loss will occur due to decreased root yield as well as decreased sucrose concentrations. In addition, powdery mildew will cause a reduction in purity.
Infected plants have higher concentrations of sodium and amino-nitrogen in the roots.
The decreased purity will reduce the amount of extractable sugar. The fungus produces spores called conidia. The conidia blow in the wind, and some will land on sugar beet foliage. The conidia then germinate and start growing. The fungus grows vegetatively by producing strands called hyphae.