Gramoxone on leaves. Plants can usually overcome this damage if it is isolated. Symptoms can be varied.
Surflan damage in young primocanes
Orange rust is a systemic fungal disease and infected plants never recover. Orange spots occur on the undersides of leaves, but can appear on canes.
Small white dots throughout a leaf typically found in lower dense foliage is a result of spider mite infestation. Mites and eggs can be seen on the underside of leaves along with delicate webbing.
Pierces disease is a bacterial disease that is lethal to grapevines, and has been detected in wild blackberry in western North Carolina. At this time, it is not thought to be a problem in blackberry.
Veins are yellow or necrotic, leaves have ringspots or yellow blotches (go to virus section)