Bacterial leaf spot is caused by Pseudomonas species. Phyton and other copper products are very toxic to bacteria as well as many fungi. However, pesticides are only marginally effective against bacterial diseases unless coupled with sound cultural practices. Since bacteria are spread by water splash, insects, handling and pesticide applications, diseased plants should be promptly isolated from healthy plants and discarded. Adequate space should be provided to allow for quick drying after watering. Discontinue overhead watering when bacterial diseases are evident. Reduce relative humidity and avoid prolonged periods of leaf wetness by the use of fans or a combination of heating and venting.