How is barley kernel smut transmitted? What's the cure?

How is barley smut transmitted? What are the control methods? (1) occurrence regularity: there are two ways of transmission of barley smut pathogen: one is that the black powder (chlamydospore) is mixed during threshing, the chlamydospore adheres to the seed surface, and after barley sowing, the chlamydospore germinates into hyphae and invades the young tissue of wheat seedlings. Another situation is that during seed storage, chlamydospores germinate at higher temperatures, resulting in hyphae adhering to the seed surface or invading the seed. After emergence, the hyphae, which lurk on the surface and inside of the seeds, continue to grow with the wheat seedlings to form diseased plants. (2) Control methods: disease-free seeds were selected for ①. ② seeds were sterilized. The seeds were soaked in 1% lime water for 2 to 3 days. Do not break the film on the surface of lime water when soaking seeds, because the film can isolate the air and facilitate sterilization. Or mix seeds with 50% Fumishuang wettable powder with 0.5% seed volume. ③ should sow seeds at the right time and sow them shallowly in order to make wheat seedlings unearthed quickly and reduce the infection of bacteria.