manganese toxicity of watermelon

Manganese toxicity-This is not an infectious disorder. However, it is important to recognize the symptoms since economic loss can occur. Also, the symptoms tend to be clustered in areas of the field where the soil pH is relatively low, thus mimicking an infectious problem. 

Figure 1. Manganese toxicity on watermelon. Note symptomatic vines are clustered in areas of low soil pH. Figure 1. Manganese toxicity on watermelon. Note symptomatic vines are clustered in areas of low soil pH.
Figure 2. Manganese toxicity on watermelon. Figure 2. Manganese toxicity on watermelon.
Figure 3. Manganese toxicity on watermelon. Figure 3. Manganese toxicity on watermelon.