Pay attention to the prevention and control of maize tumor smut

The symptoms of the disease can be infected in all parts of the ground during the whole growth period of corn, especially in the male-pumping stage. tumors of different sizes are produced in the affected part. at the initial stage, the tumor is wrapped in a white film, then turns gray, and then spreads black powder after cracking. that is, the spores of the pathogen. It is easy to produce tumor-like heaps of bean grains on the leaves, cystic gall tumors on the male ear, and large tumors in other parts. The pathogen is Yushu smut fungus, which belongs to basidiomycete subphylum fungi. the chlamydospores are oval or globose, thick, tea-brown, with fine prickly protuberances on the surface, with a size of 8 ~ 13 × 3 ~ 13 μ m. After binucleate hyphae are combined in vivo and in vitro, corn can develop rapidly in host tissue, stimulate tumor formation and produce chlamydospores. The transmission route and pathogenic conditions of the disease are as follows: chlamydospores are overwintered by chlamydospores in soil or manure, or with disease remains and seeds in soil. Chlamydospores first produce basidiospores or secondary basidiospores after overwintering, which are transmitted by airflow or Rain Water and insects, invade from the epidermis or wounds of the young tissue of the host, stimulate host cells to expand, form tumors after 2 weeks, and produce chlamydospores in the tumor after 20 weeks. The rupture of the tumor gives off a large amount of black powder, which can be infected many times a year. High temperature, drought or too much nitrogen fertilizer is easy to develop. The optimum temperature for chlamydospore germination was 26 ℃, the highest temperature was 36 ℃, and the lowest temperature was 8 ℃. The optimum temperature for basidiospore germination was 20 ℃, and the highest temperature was 40 ℃. The main control methods are as follows: (1) Sweet corn is susceptible to disease, especially the selection of disease-resistant varieties. (2) the seriously diseased fields should be rotated for 2-3 years. (3) after the disease appeared in the field, it should be removed and buried deeply in time, and ploughed deeply in time to reduce the source of primary infection. (4) seed treatment, using 1000 milliliters of 20% triadimefon EC, mixing 25 kg seeds, or 2% Suboli wettable powder 1 g, mixing 20 kg seeds, or mixing seeds with 0.2% copper sulfate, or soaking seeds with 0.1% antibacterial agent 401 can reduce the damage.