In time, the centers of the lesions turn brown and crack. A white bacterial ooze, or an effervescent exudate, can often be seen on the fruit. Fruit decay usually follows. Persistence And Transmission. The bacteria can be introduced into a field on infested seed, infected transplants, volunteer watermelons, or from natural spreading of alternate hosts.
Seed harvested from infected fruit often harbor the pathogen.
Undetected infestations can spread rapidly in transplant houses, resulting in high numbers of infected plants going into fields. Volunteer watermelons act as hosts in fields infested with blotch the previous year. Bacterial fruit blotch is favored by warm, moist environmental conditions. Hot, sunny days accompanied by thundershowers appear to favor its development and spread. Symptoms do not appear to develop under cool, rainy weather.