|
Causal Agent: (bacterium ‑ Acidovorax avenae subsp. citrulli)
Fruit symptoms
start as water‑soaked spots that rapidly enlarge. Symptoms are generally seen in the light portions
of striped fruit [wmd53.jpg].
The lesions later turn brown and crack [wmd43.jpg].
The pathogen is introduced to a field by planting contaminated seed or transplants.
Within the field, the bacteria spread to healthy plants via rain or overhead
irrigation, especially under conditions
of high humidity and temperature. The
fruit are most susceptible to infection around the time of pollination. As the fruit matures, it becomes resistant to
infection. Once introduced into a field, the bacteria can persist on volunteer
watermelon or citron [wmd5.jpg]
plants, or in their seed. Cantaloupe and honeydew melons are also susceptible
to this pathogen.
Where
this disease has occurred, watermelons and other cucurbit crops should not be
replanted in the field for at least one season, crop debris should be plowed
under, and volunteer plants destroyed. Cucurbit weeds such as citron melon should
also be controlled. Copper based fungicides
should be applied on a regular schedule at the time of flowering or earlier,
if transplants are used.