Symptoms occur in both rapeseed production areas in China and in the world. It mainly damages leaves, petioles, stems and pods. The leaves were infected with diseased, brownish-brown lesions, with slightly concentric ring veins, sometimes surrounded by yellow halos, and black moldy organisms with high humidity. The petiole, petiole, and main stem were infested at the junction and formed an elliptic to spindle-shaped ring-shaped lesion. When surrounding the lateral branch and the main stem for one week, the lateral branch or the whole plant died.
The pathogen Alternaria brassicae (Berk.) Sacc. said Alternaria brassicae, A. brassicola (Schw.) Wilts. Alternaria brassicae, A. raphani Groves et Skolko called Alternaria radicans, are all fungi Asian fungus. Among them, 95.26% of Alternaria alternata, 2.93% of Alternaria alternata, and 0.14% of Alternaria sphaeroides were found in three species. Alternaria alternata hyphae brown to grayish brown, conidial stems 14-74μm long, conidia pale black-brown, solitary or 2-3 bunches, body length 90-114μm, gills, gills long 45 -65μm, 10-11 transects, 0-6 mediastinals, slow growth on the medium, rarely form chlamydospore. Alternaria alternata mycelia olive gray to grayish black, conidiophores 35-45μm long, conidia black, cylindrical to elliptic, non-diaphragm, 8-10 spores
The daughters are long-chain, and the spores are 45-55μm in length with 5-8 cross-septae and 0-4 mediastinal segments. They grow fast on the culture medium, and the colonies are black soot-like, with rings and spores. Alternaria alternata mycelium green-gray to dark olive, conidiophore stalk 29-160μm long, conidia olive brown to black, inverted club-shaped, solitary or 6 spores forming a string, short or no pods The spores are 45-58μm in length and 10-25μm in length, with 6-9 transects and 3-6 mediastinals. The spores are flocculent on the culture medium, with few spores, and they can be used in culture media and rot tissues. The formation of olive chlamydospore. The first two can produce toxins.
Transmission routes and pathogenic conditions The pathogens use hyphae and conidia for winter or summer in and out of the seeds. The seed carrier rate is 60%, and the seeds carrying the bacteria cause the seeds to rot and die. In addition to seeds, the germs can grow on the sick body over the summer. The sporulation time on the sick body can last for more than 150 days. The disease can occur in the southern part of the year. It can be turned to harm, and there is no obvious wintering period. In the north, the initial infestation of mycelium and spores on the diseased body produces a large amount of spores. Sporulation lasts for more than 80 days. The spores extend from the lower leaves to the upper phyllodes, inflorescences and pods. The prevalence of this disease is closely related to species, climate and cultivation conditions. Cabbage-type rape is the most susceptible, and Brassica type is more disease-resistant. Brassica juncea plants are less resistant to disease when they are short, their branches are low, their growth is dense, and their leaf wax layer is thin. On the contrary, they are resistant to disease. The optimal temperatures for infection with Alternaria brassicae and Alternaria brassicae were 15°C and 25°C, relative humidity higher than 90%, and 48-72 hours of free water in leaves were suitable for the development and progression of the disease. The flowering period of rapeseed meets the high temperature and rainy weather, the incubation period is short, and it is easy to develop. Low-lying land for continuous use, partial application of heavy nitrogen fertilizer incidence.
Control methods (1) Selection of disease-resistant varieties such as: oyster sauce 18 and so on. (2) Carry out large-scale crop rotation, promote the use of compost made from fermented bacteria, adopt formula fertilization techniques, avoid partial application of nitrogen fertilizer, and pay attention to increasing potassium fertilizer. (3) The seeds are treated with a seed weight of 0.4% of 50% Formamide WP or 0.2%-0.3% of 50% acetaminophen wettable powder. (4) Apply 75% chlorothalonil wettable powder 600 times or 40% Dafudan or 80% Dasheng M45 WP 500 times, 64% antivirus WP 500 times, 50% Due to wettable powder 1500 times, 80% spray WP 800 times, but also with 12% green milk emulsion 600 times or 1:1: 150 times Bordeaux spray. (5) The effect of seed dressing with 0.2% of adriamycin or 0.2% of imidazole and 0.2% of adventitious copper in foreign countries is very good. However, cruciferous vegetables such as rapeseed are sensitive to copper, and they can no longer increase the dose when they are used, so as to avoid phytotoxicity.
Foley catheter, HSG catheter, Cervical ripening balloon
Anesthesia Medical Co., Ltd. , http://www.sinoanesthesia.com