Experiments at two sites in Florida tested the effect of composted organic amendments on bacterial wilt of tomato. At one site, yard waste, mushroom compost, and yard waste plus poultry litter suppressed bacterial wilt compared to sewage sludge, yard waste plus cow manure or no organic amendments. On the other site, only mushroom compost reduced disease incidence compared to controls. Site differences were attributed to possible differences in pathogen strains at the two sites. Beginning below the soil line, a wet, black stem lesion spreads and eventually girdles the shoot.
Stands are poor, plants appear sickly, and leaves wilt and die.
This fungus also causes a stem rot in tomatoes. Seed cutting knives and equipment not cleaned after cutting infected tubers can contaminate healthy tubers. Bacteria may be spread in the field by seed corn maggots or seed potato maggots which have fed on infected plants. Planting only disease-free certified seed, sterilizing seed cutting knives and equipment, and controlling maggots reduces the incidence of blackleg. Cereal crops are excellent rotational crop choices.