Smut is a non-systemic infectious disease, which does not spread through seeds and soil. It infects the ovary from the flower organ when the millet blooms, and it was infected with the disease that year. The incidence of millet flowering is high in rainy years and low in dry years. The environmental factors inducing the disease are sunshine hours and relative humidity at flowering stage of millet. When the sunshine hours are few and the relative humidity is high, the flowering period will be prolonged, the chances of bacterial infection will increase and the incidence rate will be high. Symptoms: Generally, there are no symptoms before heading. Shortly after heading, a fungus gall appeared on the ear, and the ovary expanded into an oval shape, slightly larger than the healthy grain, covered with a yellow-white film, which contained a lot of black powder, that is, the pathogen winter spores. The film is strong and not easy to break. Usually, the whole ear chamber is diseased, a few ovaries are diseased, and the diseased ear is light. The diseased ears in the field are mostly upright and not drooping.
Control methods: planting disease-resistant varieties, selecting and keeping single-harvested disease-free seeds. The seeds were treated with 25% pentachloronitrobenzene wettable powder, 15% triadimefon wettable powder or 50% carbendazim wettable powder, all of which accounted for 0.2%-0.3% of the weight of the seeds.
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