Chestnut disease prevention and control technology
October 21 06:01:56, 2018
(1) Distribution and damage, also known as blight and blight, is a worldwide chestnut disease. Because American chestnut and European chestnut were extremely resistant to disease, in the early 20th century, the disease was widespread in Europe and the United States and almost destroyed all the chestnut forests. Chestnut in China is considered to be highly resistant to diseases, but many provinces and cities in China, such as Liaoning, Hebei, Henan, Shandong, Anhui, Jiangsu, Jiangxi, Guangdong, Guangxi, and Hunan, have occurred in some places, and some are still very Seriously, it even caused large-scale chestnut to be destroyed and was destroyed as a domestic and foreign quarantine target. (b) Symptoms of Infestation Trees, seedlings, mainly occur on the trunks and branches, and the lower branches of the canopy are susceptible to disease. In the early stage of the disease, lesions are watery, round or irregular brown lesions, the diseased skin is slightly swollen, the cortex tissue decays, and the bark of the late stage is indented and sub-shaped. The weather was damp and orange-yellow conidium horns spilled over the seats. The autumn seat changes to dark brown. The ascospora shell is formed inside it. The germs mainly spread in the host cortex. When the disease is severe, the surface of the xylem can also infect, causing a serious decline in tree vigor. When the lesions surround the trunk, the upper branches gradually wither and turn yellow and then fall. (c) The pathogens are caused by fungi of the genus Ascomycota, Ribosomalis, Securidae, endocarpium, and parasitic endospora. (4) The pathogenic bacteria of the disease onsets the wintering of mycelium and sub-spots on the diseased tree, starts to move after the temperature rises in the following spring, and produces orange-yellow patches on the lesions in April. In wet weather, the conidia are squeezed out of the sub-seats. angle. The bacteria spread through wind, rain, insects or birds and invade the wound. The long-distance transmission of germs is through the transmission of asexual propagation materials with diseased seedlings. The disease is closely related to temperature and temperature, with heavy rainfall, high humidity, and the most serious disease. The relationship with the situation on the ground is also very close. If the soil is thin and the tree is weak, the incidence is heavy. Chestnuts with high groundwater levels or poor drainage are also affected. (E) Control methods 1. Strict quarantine. Prevent diseases from passing in or out of diseased seedlings, scions, rootstocks, etc. If seedlings need to be transferred from the wards, except for strict inspection, 1:1:160 Bordeaux mixture, 3-5 Bomer Degree of lime sulfur or other miscellaneous agents after spraying colonization. 2. Increase tree vigor, strengthen management, reduce and protect wounds. Wounds should be sterilized and protected with Boer's liquid as soon as possible. Branches can be painted white in winter and summer to prevent sunburn and freezing injury and to avoid mechanical damage. Strengthen the prevention and control of stem pests in trees. 3. Drug treatment, scrape the skin, and then apply chemical agents. In the onset stage, 1:10 sodium carbonate, 25% wettable carbendazim powder 1:100, 1:1.5 Bordeaux mixture, antibacterial agent (401) 200 times, 0.1% Pingpingjiao, etc. were used. 4. Screening for resistant varieties and selecting disease-resistant varieties.