Symptoms of downy mildew in rape

The pathogen can infect leaves, stems, flowers, pedicels and pods. After the leaves were infected, the light yellow spots appeared at first, and the expansion of the disease spots were irregularly shaped yellow-brown spots limited by the veins of the leaves. There was a frosty mildew layer on the disease spots on the back of the leaves, which were sporangia and sporangium peduncles. In severe cases, the whole leaves turned brown and withered. After the stem stem, branch and pedicel are infected, the primary chlorotic spot in the disease part, and then the disease spot expands into an irregular yellowish-brown spot, which is also covered with a layer of downy mildew like the leaf. After pedicel onset, often swollen, deformed, floral organ large, green bibcock, smooth surface, frost-like mildew layer also appeared above. When the whole plant was seriously damaged, the whole plant was covered with mildew, brown and withered.