Avoid excessive irrigation before flowering. Cultivars with cv. Williams in parentage may be more susceptible. Symptoms are usually not evident until late in the growing season. Leaves may suddenly discolor, with brown tissue between veins and green tissue along veins.
Leaves remain attached.
Browning of pith inside stem of infected plants. Disease progresses more quickly in older than younger plants, regardless of temperature. Can survive 3-5 years. Avoid susceptible cultivars for 3 years. Click on an image to display it in larger detail.