|
|
 |
|
Figure 1. Bacterial wilt.
|
 |
|
Figure 2. Bacterial wilt. |
|
Bacterial wilt is a common and destructive disease of muskmelon and cucumber. It is less common on squash and pumpkin. SYMPTOMSSymptoms of bacterial wilt may develop anytime during the summer, but it is more pronounced in late spring or summer soon after transplants are placed in the field. Diseased plants initially are dark green and wilt slightly during mid-day. Soon thereafter, the plants go into an irreversible wilt and die. To diagnose bacterial wilt, cut the stem near the soil line and
squeeze the cut end between your fingers. Then place the tip of a knife
blade on the bead of sap that has extruded from the stem and slowly pull
the knife blade away. If a slimy string develops between the blade and
the vine, then the plant is probably infected with the bacterium. On
healthy plants, the slimy string does not develop. Alternatively, place
a small section (1/4inch thick) of the lower portion of the stem in a
shallow dish containing water. After a few minutes, you should see a
cloud of slimy bacteria oozing from the cut end of the vine. DISEASE CYCLEThe cucumber beetle transmits the bacterium that causes the disease. The
beetle survives the winter as an adult in debris at the field edge. In
the spring, the adults, contaminated with the bacteria, migrate into the
field and begin to feed on transplants. The bacterium is introduced into
the plant through feeding wounds. Once inside, the organism blocks the
water-conducting tissue, which results in wilting. CONTROLThere is no control of bacterial wilt once the plants become infected. None of the cucumber and muskmelon varieties currently in use have resistance to this disease. Therefore, it is important to prevent transmission of the bacterium by controlling cucumber beetle feeding. Early season control is very important to prevent establishment of the disease in the field. Growers may incorporate a systemic insecticide (Furadan) into planting rows at the time of planting or apply contact insecticides to the plants as soon as they are placed in the field. Monitor for cucumber beetles in the field and continue insecticide applications at regular intervals. For more details on insecticides labeled for cucumber beetle control, see publications on commercial vegetable pest control. Alternatively, cover the crop with a floating row cover. This serves as a physical barrier to the cucumber beetles.
|
|
It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all persons shall have equal opportunity and access to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age, or disability. Kansas State University is an equal opportunity organization. These materials may be available in alternative formats. |
|
Web updated 9/01/06 |