Causal Agent: (fungus – Myrothecium roridum)
This fungus causes small, dark brown circular lesions on leaves (Image 1). These lesions can coalesce (Image 2). The disease is favored by wet weather conditions that favor the development of other foliar pathogens and can be controlled by the protectant fungicides used to control these pathogens. The disease occurs infrequently and has been observed mostly in the Lower Rio Grande Valley.