What is the black corn?

Corn is one of the most important food crops in China, and it is planted all over the country. As a kind of cash crop, growers may encounter nodules of about 4cm and 14cm on corn. At first it is white, then it turns gray or white, and a large amount of black powder will appear when it is broken. So, what is the black corn?

What is the black corn?

The black corn is a pathogen called corn smut. Powdery mildew fungus can be susceptible to disease from seedling to adult plant, and any young shoot tissue with meristematic ability can be infected and form tumors of different sizes and shapes. The tumor is white or light purple at first, then becomes gray gradually, and a large amount of black powder will be released after rupture.

Second, what is the incidence law of corn smut?

The pathogen of maize smut is fungi (basidiosporium), and the powdery mildew in the tumor is the teliospore of the pathogen. Winter spores overwinter in soil, on the surface, on diseased bodies, and in soil manure.

The overwintering winter spores became the primary infection pathogen in the second year. Under suitable conditions, they germinated and produced basidiospores and secondary basidiospores, which spread to the young meristematic tissues of maize, such as leaves, nodes, axillary nodes, male and female ears, and grew and spread in the tissue, and produced a substance similar to auxin, which stimulated the cells of the host local tissue to divide vigorously and gradually swelled to form a disease. The tumor matured and ruptured, and then spread black powder (winter spores) for re-infection.

The winter spores had no dormant period, and could be re-infected many times during the maize growth period, and spread rapidly in the heading and flowering stage, forming the peak period of the disease, until the infection stopped after the corn matured.

What pesticides are used by corn smut fungus?

Before corn emergence, the herbicides with bactericidal effect can be sprayed on the surface with 15% trimethoprim, with a dosage of 0.4% of the seed amount; when corn is about to heading, 1% Bordeaux solution is sprayed, which has a certain protective effect; about 10 days before corn heading, 50% thiram wettable powder is sprayed 500-800 times to reduce the re-infection of smut.