Bacterial spot causes more losses to the Florida tomato industry than any other disease. Although fruit spotting is a problem, primary losses are due to leaf infection which causes defoliation resulting in yield reduction and fruit defects such as cracking, sunscald, and black shoulder. Breeding for resistance to bacterial spot has been difficult, primarily because there has not been a good source of resistance.
Over the last 2 summers we have screened over 300 accessions in the field, which had reported tolerance or resistance to any bacterial pathogen of tomato. Hawaii 7998 appears to be resistant to bacterial spot. Although inoculated with 108 bacteria/ml in the field, no lesions could be identified on the plants. Work to identify the genetics of this resistance is underway. Hawaii 7998 is reported to have bacterial wilt tolerance as well. Other genotypes with good levels of tolerance are: Ohio 4014-4 (Frost tolerant tomato TGC 32:45), Ohio 4013-3, Heinz 1568, [(Sub Artic Delight x Fla. MH-1) x Heinz 603], L556, C-28, PI 127813, Heinz 603, and PI 379032.