Its symptoms vary according to different environmental conditions. Generally speaking, from the jointing stage to the heading stage of wheat, spindle-shaped lesions from light green to yellow appear between the veins on the leaves, and then gradually expand and heal into irregular light brown patches with scattered black spots, that is, conidia of the pathogen.
Sometimes the lesion is yellow and connected into stripes, and the veins are yellow-green. At first glance, it looks like wheat yellow dwarf disease, but the stripe edge is wavy and runs through the whole leaf. In severe cases, the yellow leaves are long and waterlogged, spreading from left to right, making the leaves white and black spots (conidia) grow on them.
The diseased leaves generally develop upward from the lower leaves, and the diseased spots extend from the leaf sheath to the stem, infecting the spikelets and turning them white. Sick leaves sometimes turn yellow, thin and droop quickly, but they don't die soon. Some diseased leaves have small spots, but the leaves are dry and then spread out gradually.
Distribution range of wheat leaf blight
Wheat leaf blight is a worldwide wheat disease, which occurs in different degrees in the main wheat producing areas of the world. This is the most important disease affecting wheat production in South Asia. It happened in the United States, Canada, Australia, India and Russia. According to reports, the global area of cultivated wheat leaf blight is about 25 million hectares, including 6,543,800 million hectares in South Asia.
In China, with the global warming, the change of farmland environmental conditions and the popularization of dwarf wheat, the occurrence of wheat leaf blight is more and more frequent, and the occurrence range has spread from the prone areas such as northeast and northwest wheat areas to Huanghuai wheat areas, middle and lower reaches of the Yangtze River and south China wheat areas. Mainly distributed in Heilongjiang, Jilin, Liaoning, Henan, Hebei, Shandong, Inner Mongolia, Shanxi, Shaanxi, Gansu, Xinjiang, Guangdong and other regions.