Particularly, the disease will be noticeable on infected plants as soon as the hop shoots start to emerge with the latent period being approximately 10 days at 12 and 15 °C compared to 5 days at 18-27 °C. These spore-covered shoots that emerge from infected buds are called “flag shoots” and will be stunted with distorted leaves. Periods of rapid plant growth are the most favorable for infection.
Notably, the disease becomes evident on contaminated plants when hop shoots start to sprout, with a typical incubation period of approximately 10 days at temperatures between 12 and 15 °C versus 5 days at warmer temperatures. The spore-covered shoots that emerge from infected buds are known as “flag shoots” and will exhibit stunted growth and distorted leaves. Rapid plant expansion is the most conducive to infection.