
Figure 3. A. Early stages of powdery mildew infection in muskmelon leaf. Notice several whitish and small spots (white arrows) developing on the upper surface. B. Early stages of powdery mildew infection in Beit Alpha cucumber leaf. Notice several whitish and small spots (white arrows) developing on the upper surface. C. Advanced powdery mildew disease in squash, where all small spots have coalesced homogeneously.