Pumpkin and Watermelon Herbicide Injury Symptoms – In Photos – Vegetable Crops Hotline

Pumpkin and Watermelon Herbicide Injury Symptoms – In Photos

Throughout the growing season, vegetable crop farmers often report suspected herbicide drift injury. Each type of herbicide results in specific types of injury. Knowing what to look for can help us narrow which herbicide or herbicide mode of action could be responsible.

To document how watermelon and pumpkin respond to various herbicides, we sprayed a reduced rate (1/10th of the recommended rate) of 9 herbicides (Table 1).

Table 1. Herbicide active ingredient, group number, and rate.

Observations:

  • Symptoms were similar for watermelon and pumpkin with a couple exceptions:
    • Pumpkin appears to be more sensitive to dicamba than 2,4-D. The opposite appears to be true for watermelon, which was more sensitive to 2,4-D than dicamba.
    • Clomazone resulted in very mild bleaching injury on watermelon leaves only. In contrast, mesotrione, another group 27 herbicide, caused severe bleaching injury on the watermelon growing points.

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