All aerial parts can be injured by this mite. Young, new growth is very susceptible and will develop abnormally. Flower buds may not open or blossoms may be destroyed and drop early. Leaves often appear crinkled, twisted, and stunted. Leaf yellowing and dieback can also occur.
Severe symptoms can be apparent even when mite populations are low.
Monitoring The undersides of mite-infested leaves may be covered with fine webbing. In severe infestations, the foliage becomes yellow, then grey, then dry, and finally dies. To avoid a build-up of mite populations, the under surfaces of leaves should be closely inspected for mites every 10 days throughout the growing season. Check individual leaves that appear stippled, mottled, yellowish, or bronzed. A simple but effective diagnostic tool is to breathe on the back of the leaf.