Non-Pathogenic Causes

Seed Corn Maggot inside a watermelon stem

Image 1: Seed Corn Maggot

Watermelon seedling killed by lightning

Image 2: Death by Lightning

Watermelon Vine damage caused by movement on plastic

Image 3: Movement on Plastic

Anasa wilt caused by squash bugs

Image 4: Anasa wilt (squash bugs)

Squash bugs and a dime, roughly the same size

Image 5: Squash bugs

Yellowing caused by glyphosate (herbicide) contact

Image 6: Glyphosate damage

scattered wilting caused by trifluralin (herbicide) contact

Image 7: Trifluralin damage

discoloration and swelling of the crown caused by Trifluralin (herbicide)

Image 8: Trifluralin crown damage

Agents that can cause seedling death that resemble damping-off include the seed corn maggot (Image 1) and lightning damage (Image 2). Wind movement of young plants on plastic mulch can cause damage to the stems, leading to wilt (Image 3). This problem disappears once vines are able to anchor to something.

Anasa wilt (Image 4), caused by the squash bug (Image 5), can be mistaken for Fusarium wilt. Watermelon growing next to brush are more prone to this problem.

Herbicide injury can cause symptoms that resemble those caused by pathogenic fungi. Glyphosate (herbicide) can cause yellowing (Image6). Trifluralin (herbicide) can cause scattered wilting in a field (Image 7) and affected plants will also exhibit discoloration or swelling of the crown area (Image 8).

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