Answer: Unfortunately, I can't track your first question so I do not have the full story. However, the most common problem with this plant is probably scale insects. Although scale can be successfully treated with horticultural oil, they can be difficult to control on a thick, dense planting. According to Michael Dirr's "Manual of Woody Landscape Plants" the plants may also be infected with mildew, anthracnose, crown gall (a bacterial disease), leaf spots, and additional insects such as thrips and aphids. You might want to consult with your county extension as to the true nature of the problem and how to treat it. They should also be able to assist with rhubarb problem.
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