Large, irregular or circular tan spots without definite margins. What’s that on the leaves and pods? for 3 years I have grown sweet peas from seed and every year by July/ August the plants have died off from this powdery mildew (I think that's what it is). Favored by wet conditions. 1 Replies 1103 Views February 23, 2014, 19:12 by mumofstig : Sweet Pea Started by puravida on General Gardening. If plant leaves are turning white and dying, the underlying reason is most likely either sunscorch or powdery mildew. Avoid overhead irrigation. Sweet pea’s leaves are spiral, so they adjust to the direction easily, while you get beautiful flowers on top. Should my sweet peas have these white spots on the leaves? Seed decay The first year I got great healthy plants and even they succumbed. I was looking at them today and noticed that a lot of the leaves had this white pattern on them. Oak leaves Started by whistler on General Gardening. Powdery mildew is the most common occurring plant fungal disease. Lower leaves are first affected. There are white fuzzy spots growing on my peas. Powdery Mildew strikes again!! This further means that you can easily grow Sweet pea in your garden – it looks great, smells even better, blooms every year, and it is easy to grow and maintain – as this is a cultivated plant. I have not had any virus infection for several years now but the most common one that I have come across has been the yellow leaf one. Fungus is specific to sweet pea and survives in sweet pea refuse. Infected leaves often drop. Its appearance, when first noticed, is characterized by spots or patches of white to grayish powdery growth on the upper surface of leaves and their stems. This summer has unusually been particularly wet and cold and has given the sweet peas a lot of challenges. I'm attemping my first garden, and have a bunch of sweet peas starting to nicely climb up a trellis. 9 Replies The most natural and healthy diet for humans is an omnivorous diet, and not a plant based diet, or a meat-based diet per se. A fungicide may be necessary in some severe cases. 3 Replies 1677 Views November 07, 2010, 19:35 by whistler : sweet pea Started by chickpeacurry on General Gardening. Rotate with other crops for 2 years.