Control of White Silk Disease of Jasmine

White silk disease of jasmine is the most serious disease of jasmine. When the disease is serious, the plant will die and the yield will be greatly affected.

Suzhou, Hangzhou, Shanghai, Nanjing, Fuzhou, Taiwan.

[symptoms] the disease occurs in the root neck and root, and can spread to the lower leaves under suitable conditions. The part of the root neck became brown and rotten, gradually spread and spread, producing a white silk-like film, mostly radiating, and the edge was especially obvious. the silk-like hyphae could spread to the soil near the root neck, and in severe cases, the whole soil was full of white hyphae. Later, the sclerotia was formed on the mycelium film, and the sclerotia was white at first, and gradually deepened into yellow, tea brown to dark brown, rapeseed-like size. After cortical decay, the leaves withered and fell off, and the whole plant died in severe cases. Under very humid conditions, the hyphae can spread directly to the lower leaves, producing a large number of white silk membranes, which surround the lower branches and leaves, making the leaves appear water stains and produce hyphae on the silk membranes.

[pathogen] the pathogen is fungus. Sclerotinia uniformis (Sclerotiumrolfsii). Belong to half-known subphylum, hyphomycetes, non-spore order, small sclerotia genus. The sclerotia was white at first, then changed gradually from light yellow to chestnut brown to tea brown, the surface was smooth, spherical or subspherical, with a diameter of 0.8-2.3 mm, which was very similar to rapeseed. The optimum temperature for the development of the pathogen was 32-33 ℃, the highest temperature was 40 ℃, and the lowest was 8 ℃. The range of acid and alkali resistance is pH 5 to 9.

[incidence regularity] there are more than 200 kinds of pathogens. Overwintering with sclerotia or hyphae on soil, diseased plant residues and weeds. Sclerotia survive in soil for more than 4 years, but the survival time is very short under high humidity conditions and is not resistant to flooding. Bacteria spread by hyphae in the soil, and long-distance transmission depends on running water or diseased seedlings, diseased soil, disease basin for human transfer. When changing pot soil, it is easy to get sick when using garbage soil and vegetable garden soil, continuous cropping or continuous use of diseased basin soil is serious, and high humidity is easy to occur.

[prevention and control methods]

(1) Horticultural control: rotation, concentrated treatment of diseased soil, it is better to pour it into the paddy field, the potted soil is taken from the disease-free land, and the paddy soil is better. Organic manure should be fully mature; reproductive materials should be cut from disease-free plants; and dense stacking should be avoided when overwintering in greenhouse.

(2) removal of diseased plants and soil disinfection. If the damaged plants are found in the early stage, they should be removed in time and burned or buried deeply. 86.2% of the copper masters are irrigated with 800-1200 times, 50% desenamine 500-fold solution or lime powder. The removal of diseased plants should be carried out before sclerotia formation.

(3) Pesticide control: 1000 grams of 50% bacillus per 666.6 square meters; irrigate 1000 times of 50% Dysenamine at the initial stage of the disease, and sprinkle it again after 7-10 days to kill germs in the soil. The soil around the stem base of the plant was sprayed with 1000 times of thiophanate methyl or 1000 times of carbendazim to inhibit the spread of the disease. Pour other fungicides later; the basin soil can use 82 Trichoderma bran preparation (the product of the Department of Plant Protection of Zhejiang Agricultural University), remix the human soil according to 0.5% of the soil, and use it after filling the basin; you can also dig out part of the basin soil and load it into the soil mixed with the preparation.

(4) physical control: the basin soil is sterilized by heating method.

(5) Biological control. Using antibiotic Trichoderma harzianum (Trichodermaharzianum) to control white silk disease of jasmine flower has a good effect. First cultivate the strain of Trichoderma, and then mix it into the sterilized wheat bran to form Trichoderma preparation. When Trichoderma preparation is used, and then evenly mixed with fine soil to the soil, the soil should maintain a certain humidity, promote a large number of Trichoderma growth and reproduction in the soil, in order to inhibit the growth of white silk fungus, so as to achieve the purpose of disease prevention.

(6) rational fertilization. The application of non-mature organic fertilizer on the surface of the soil will aggravate the occurrence of white silk disease, so organic fertilizer (such as barnyard manure, etc.) should be used as base fertilizer and buried deep in the lower layer of the soil. If used as topdressing, it must be fully ripened before it can be applied.