Combatting Bacterial Spot on Tomatoes and Peppers

Fresh market tomato is the No. 1 vegetable crop in Florida with 32,200 acres harvested for a total crop value of $453.1 million in 2015, while bell peppers generated a sizeable $220.5 million. These economic mainstays are so successful because of research and development by scientists in the UF/IFAS tomato breeding program and Plant Pathology Department to combat bacterial spot disease.

Bacterial spot on tomatoes and peppers is a debilitating disease that affects crops in warm, moist environments (such as Florida) by attacking the foliage, stems and fruit. Flowers may also become infected with pedicel infection often resulting in blossom drop and associated yield loss. Under optimal environmental conditions for disease development, the majority of the crop can be severely afflicted.

UF/IFAS researchers have led the charge against bacterial spot for the past 50 years, and their research has made a major impact on basic biology and disease management practices. This included the first documentation in a field setting of a bacterial pathogen showing resistance to the antibiotic streptomycin, resulting in growers using alternative control strategies. Later, the researchers identified and characterized copper resistance in the pathogen and determined that it was widespread in Florida. Other research efforts have resulted in the identification of recessive and dominant resistance genes in tomato and pepper. The researchers have also significantly contributed to identifying extensive pathogen variation in a worldwide collection of strains, and they identified genetically distinct strains that resulted in the naming of three new bacterial species within the bacterial spot pathogen complex. UF/IFAS plant pathology researchers also identified novel secreted virulence effectors in pathogen genomes that were verified by functional analysis.