Where it stops indicates how deep the water penetrated. Deep, infrequent waterings allow air to return to the soil between irrigations, encourages roots to grow deeply, avoids root rot and flushes away salts. Determine when to irrigate again by testing the soil 2 inches below the bush's canopy. If the soil is moist, wait a few days and test again. If it's dry and crumbles to the touch, irrigate.
Infections appear on new growth after warm days are followed by cool, damp night.
New leaves may become curled or twisted and shoots will look badly deformed. The fungus may infect older leaves. Often, the upper surface of the leaf appears normal, but there is extensive fungus growth on the leaf undersurface. Reduce infection by keeping the area around the bush free of debris. Prune out and destroy diseased canes and leaves.