I have a “fence” of golden bamboo that is approximately 8 years old. It has a black coating on the leaves as well as small white flying insects that scatter when I move the branches. Any ideas as what has invaded my yard?
While we cannot diagnose plant problems remotely, what you describe sounds a bit like aphids or whitefly.
This page (now archived) from the American Bamboo Society website also has information on insect pests that affect bamboo. Here is an excerpt, about aphids:
“Aphids love bamboo! There are over 50 species of Asian aphids known to feed on Asian bamboos. A good example is Astegopteryx bambusifoliae, which sucks sap from the leaves of Bambusa, Phyllostachys, and Dendrocalamus throughout Southeast Asia. It over-winters on the bamboo plant, where it sucks sap from the leaf undersides and culms. It is most common during the winter and spring, and disappears during hot summers. It is controlled by ladybeetles. In general, aphids aren’t a major problem since there are so many organisms that prey on them, but they can appear in an occasional outbreak that causes wilting of the leaves and shoots, a reduction in vigor, and stunted growth. They can also transmit fungal diseases, such as black mildew.” Bamboo mites are also common in our area.
University of California at Davis “Giant Whitefly” page mentions a black mold that forms during whitefly infestations.
To determine which insect is invading your bamboo, you may want to take a bagged sample to a Master Gardener Clinic for identification. For information about Clinic hours see their website (Plant Clinic Schedule).