|
What is it?
Bacterial wilt, or the bacterium erwinia trachephila primarily infects cucumbers and muskmelons but is can also attack pumpkins and squash in the curcurbit family. Bacterial wilt does not affect watermelon plants.
What does it look like?
Erwinia trachephila damage shows up at first as dry leaves which have wilted. The edges of the leaves may appear ragged as if they were chewed. Often the leaves will recoup from the wilting process during the night when moisture is heavy in the air, but come morning they will wilt and shrivel once again in the sun. This process leads to eventual death of the plant. To confirm bacterial wilt you can cut the plant on a wilted stem area. If you cut near the base of the plant, and then squeeze that section a white sap that is milky looking will appear, oozing out in a thin thread-like stream.
How does it manifest?
Erwinia trachephila primarily is present in areas where the weather is cool and the climate has a moderate amount of rainfall. Bacterial wilt bacterium can thrive in these conditions. Bacterial wilt is spread by the striped or spotted cucumber beetle. Erwinia trachephila overwinters on the bodies of these beetles, and when they emerge to feed on curcurbit family plants like cucumbers and muskmelons, they spread the bacterium onto new plants which were previously healthy. Once the cucumber beetles begin feeding they can infect an entire plant over a fifteen day period causing a quick death to the plant.
What can you do about it?
In order to be effective, insecticides must be applied prior to the plant being infected with bacterial wilt. Once erwinia trachephila is present there is no chemical control that will stop the damage to the plant from resulting in death. To control cucumber beetles, and prevent spread of bacterial wilt that has overwintered on their bodies, spray them with carbaryl or diazinon containing insecticides as soon as they are spotted. Unfortunately, there are no resisitant varieties of muskmelon, but there are resistant varieties of the other affected curcurbit plants which you can plant. For those plants which have been infected with the bacterium, your only choice is to remove and destroy all infected plants making sure to remove any plant debris.
| 
