Splashing water from raindrops or irrigation helps to move spores from infected plants to nearby healthy plants. The motile zoospores can swim in pools of standing water, drainage ditches or irrigation systems to infect plants far away from the original disease site. Non-Chemical Effective disease control begins with prevention and proper water management to minimize excess moisture on the plants. Avoid handling diseased and healthy plants at the same time since spores can be unknowingly transferred by workers during handling. Immediately remove and destroy any plants suspected of being diseased or showing signs of infection.
Monitor plants regularly in order to detect disease outbreaks early.
Read label directions carefully and apply chemicals responsibly. Agrios, G. N. 1988. Plant Pathology, 3rd edition. Raabe, R. D, I. L. Conners, and A. P. Martinez. Checklist of Plant Diseases in Hawaii.