Figure 1. Lesions of anthracnose on pumpkin fruit often consist of round, dark rings on the fruit surface.
Figure 2. Anthracnose lesion on pumpkin in comparison to a quarter.
Figure 3. Anthracnose lesions of differing ages on pumpkin.
Bacterial leaf spot
Figure 1. Lesions of bacterial leaf spot on a pumpkin leaf are often a light brown and maybe somewhat angular in shape.
Figure 2. Close up of lesions on pumpkin of bacterial leaf spot.
Figure 3. The bacterial spot lesions on the leaf in the foreground are a darker necrotic shade than the lesions in Figure 1 and 2.
Figure 4. A specialty pumpkin with lesions of bacterial leaf spot of pumpkin. Note that lesions may have a water-soaked appearance. Older lesions may have a light necrotic center.
Figure 5. Lesions of bacterial spot on this pumpkin appear necrotic and may have small depressions in the center.
Figure 6. This immature pumpkin has lesions of bacterial spot of pumpkin. The lesions have the appearance of light necrotic scabs. The larger lesions are probably where one of the bacterial spot lesions became infected with a fungus that started in one of the bacterial spot lesions.
Figure 7. Bacterial spot lesions on a pie pumpkin.
Figure 8. Several necrotic lesions caused by bacterial spot of pumpkin can be observed here. One lesion is much larger and has probably been infected by a secondary fungus.
Figure 9. Typical lesions of bacterial spot can be observed on this pumpkin along with one that has been infected by secondary fungi causing it to rot through the pumpkin rind.
Cercospora leaf spot
Figure 1. Cercospora leaf spot of pumpkin.
Figure 2. Cercospora leaf spot of pumpkin.
Figure 3. Cercospora leaf spot of pumpkin.
Figure 1. Downy mildew of pumpkin. Lesions tend to be angular and are initially chlorotic. Note older lesions have turned necrotic.
Figure 2. Downy mildew of pumpkin.
Figure 3. Under moist conditions, the causal fungus for downy mildew of pumpkin can be observed to sporulate on the underside of the leaf.
Figure 4. Sporulation on the underside of a pumpkin with downy mildew. Note pumpkin leaf is wet.
Figure 5. Downy mildew of pumpkin. Sporulation is visible on the underside of the leaf near the vein where moisture has accumulated.
Fusarium fruit rot
Figure 1. Fusarium fruit rot of pumpkin. Note gray/white sporulation.
Figure 2. Fusarium fruit rot of pumpkin. Note sporulation in center of lesion.
Figure 3. Fusarium fruit rot of pumpkin.
Figure 4. Fusarium fruit rot of pumpkin.
Gummy stem blight / black rot of pumpkin
Figure 1. Gummy stem blight lesion on a pumpkin leaf.
Figure 2. Black rot of pumpkin. Note target spot-like pattern of lesion.
Figure 3. Close-up of black rot lesion on pumpkin.
Phytophthora fruit rot
Figure 1. Phytophthora fruit rot of pumpkin.
Figure 2. Phytophthora fruit rot of pumpkin.
Figure 3. Phytophthora damping off of pumpkin.
Figure 4. Phytophthora blight of pumpkin on crown.
Figure 5. Phytophthora fruit rot.
Figure 6. Phytophthora fruit rot.
Figure 7. Phytophthora fruit rot. Growth and sporulation of causal fungus is often on the underside of fruit due to increased moisture.
Figure 8. Phytophthora blight lesion on stem.
Figure 9. Phytophthora blight lesion on stem.
Figure 10. Phytophthora blight has affected the pumpkin plants in the lower area of this field. Note the wilted and dead plants in the low area shown here.
Figure 11. Often the first symptom of Phytophthora blight of pumpkins is the wilt and decline of plants caused by lesions on stems.
Figure 1. Plectosporium blight of pumpkin. Lesions are most common on the handle or lower stem.
Figure 2. Plectosporium blight of pumpkin on stem.
Figure 3. Plectosporium blight of pumpkin.
Figure 4. Plectosporium blight of pumpkin.
Figure 5. Plectosporium blight of pumpkin on leaf.
Figure 1. Powdery mildew of pumpkins can be easily recognized by the talc-like lesion on the upper and lower surface of leaves.
Figure 2. A fungicide trial for products for powdery mildew of pumpkin. The untreated row on the right has significant symptoms of powdery mildew. The adjacent row to the left has been treated with a systemic fungicide and has relatively mild symptoms.
Figure 3. Severe symptoms of powdery mildew on a pumpkin leaf.
Figure 4. Powdery mildew lesions can be observed on the lower leaf in this photo. The upper leaf has light colored variegation that are sometimes mistaken for powdery mildew.
Figure 1. This pumpkin tested positive for Watermelon mosaic virus 2 and zucchini mosaic virus, both poty viruses. Note the sunken, gray, mostly circular lesions.
Figure 2. Close up of pumpkin in figure 1.
Figure 3. Poty virus on pumpkin.
Figure 4. Poty virus on pumpkin.
Figure 5. Pumpkins affected by papaya ringspot virus, a potyvirus.
Figure 6. Pumpkins affected by papaya ringspot virus, a potyvirus.