The University of California Agriculture Department recommends not planting sweet peas in the same area each year if you have problem with the fungus. As this disease infects the root system of the sweet pea plant, you may notice that the plant develops roots and stems that have decayed and turned yellow or pink. Plan the perfect garden with our interactive tool →, Image by Flickr.com, courtesy of tanakawho. Symptoms include foliage with dark green areas combined with yellow-green areas. Promote healthy growth by planting sweet pea plants in fertile, well-drained soils that have been treated with a fungicide. Learn which plants thrive in your Hardiness Zone with our new interactive map! Aphanomyces, Pythium, Fusarium and Rhizoctonia can all result in the yellowing of the leaves of the sweet pea plant. As they continue to decay, they turn a brownish-black colour. The powdery mildew spores are spread through the air. These are: Pea enation mosaic virus (PEMV) Bean yellow mosaic virus (BYMB) Pea mosaic virus (PMV) Basic Problems with Sweet Peas Leggy seedlings are caused by high temperatures of insufficient light. Unfortunately, no sweet pea varieties are resistant to this disease, so close monitoring in the spring and summer is essential. Each type of fungi thrives in slightly different temperatures, but they are all within the range of 17.7 to 30.5 degrees C. As the fungi spreads throughout the plant, it produces spores which aid in the spread of the disease. The deficiency is frequently seen in soil with a very high pH. The virus, which can kill your plants, is spread by thrips. All Rights Reserved. Sweet peas (Lathyrus odoratus) are elegant cool-season annuals with brightly colored flowers. The mosaic virus is spread by aphids, which can be treated with an insecticide and by controlling nearby weeds. Each type of fungi thrives in slightly different temperatures, but they are all within the range of 17.7 to 30.5 degrees C. As the fungi spreads throughout the plant, it produces spores which aid in the spread of the disease. Use an insecticide and control nearby weeds, including grasses. While they are generally easy to grow, sweet peas are susceptible to some diseases that can cause their leaves to turn yellow. Spotted wilt is a virus that causes circular spots on leaves that are first yellow, then brown. The leaves of infected plant starts showing signs of disease by turning yellow, and as the disease progresses, the leaves start to shrivel and fall to the ground. She has worked for several newspapers, including "The Washington Post" and "The Charlotte Observer." Sweet pea plants thrive in locations where they receive full sunlight. The mosaic virus is spread by aphids, which can be treated with an insecticide and by controlling nearby weeds. Ascochyta blight – Lastly, Ascochyta blight may be to blame for a pea plant turning yellow and dying. Reynolds holds a Bachelor of Arts in English from Florida State University. Try watering more, or more often. You may also find this article helpful: University of Illinois: Root Rots of Pea Plants, Washington State University: Sweet Peas - A Flower Garden Favorite. Spotted wilt is a virus that causes circular spots on leaves that are first yellow, then brown. Monitor the soil regularly to maintain a pH of 6.5 to 7.0, and avoid over-watering the soil. Why Are the Leaves on My Begonia Wilting? This annual plant is a member of the Fabaceae family and was traditionally used in old-fashioned English gardens. In the spring and summer months, this ornamental plant can be damaged by root rot. Your snow peas react to too much water in the same way they react to too little water: the leaves turn yellow. The fungus survives in foliage that has been removed, so do not compost infected plants. Sweet peas are members of the legume family and thrive in early spring before summer's heat wilts them. The University of California Agriculture Department recommends not planting sweet peas in the same area each year if you have problem with the fungus. For healthy growth, plant pea-plant seeds in soil with a temperature of 12.7 to 18.3 degrees C until germination. Clarkson earned a Bachelor of Arts in journalism from the University of Florida. Aphanomyces, Pythium, Fusarium and Rhizoctonia can all result in the yellowing of the leaves of the sweet pea plant.