(1) Control methods 1. Do a good job of field sanitation and remove the guava fruits that have been hit by wind and rain or other fields. 2 fruit bagging. For the prevention and control of fruit blight, bagging is the best protection measure. When the plastic bags cover the fruit, the top of the bag should be tightly closed; in addition, the fruit position of the fruit should be paid attention to when the fruit is ripe, the fruit will be too heavy, the branches will fall, and the fruits will be close. The ground is rubbed, and the damaged bacteria in the bag enter the infection. 3 Strengthen field management, pay attention to drainage and so on. 4 Orchards with more incidence should be sprayed and protected. The agent can be used 65% dexamethasone WP or 600% or 40% AI 300 times. The results will be sprayed once every 10-15 days for a total of 3-5 Times. Other agents include Rhizoctonia and Bordeaux mixture (1:2:200). Bordeaux solutions should be used to avoid phytotoxicity. 4. Guava Bacterial Wilt This disease is a new disease, the host is extensive, vegetables such as tomatoes, peppers, eggplants, fruit trees such as guava, Lianmeng, etc. have all been found. (1) Symptoms of guava infection once infected by Ralstonia solanacearum, in addition to the whole plant growth has stopped, the whole plant has no reflex luster, and it is very different from the healthy plants. The old leaves first fall off, but the upper leaves stay on the branches of the plants, but Turn yellowish white, or yellowish green, and finally the whole plant withered. (2) Prevention and control methods Because bacteria spread from the soil and spread, it is difficult to prevent and control pesticides. It is feasible to use the soil and soil method to remove the soil from the locust ward and transfer it to the new soil. Fertilizer in the whole area should be given more organic fertilizer, increase the number of microorganisms such as saprophytic bacteria in the soil, reduce the value of -, and inhibit the reproduction of bacteria. In addition, when guava is to be planted, it is important to pay attention to the early crops of the garden and avoid directly planting crops such as peppers, eggplants, and tomatoes that are susceptible to bacterial wilt, or make such crops in the garden to reduce the occurrence of diseases. 5. Guava algae spot disease (1) The main symptoms of damage are guava leaves, which cause the nutrients of the leaves to be absorbed by the algae and prematurely age. The current economic varieties such as Shibapu, pearl pull and other varieties will suffer. There are two types of illnesses. The first type of algae disease caused by green cephalosporins was the brownish-brown algae on the upper surface of the infected leaf, which slightly protruded from the surface of the leaf. Head-shaped cells appeared on the upper part of the leaf and adhered to the ascus, which was dark red-brown. The second condition is a yellow lesion in the mesophyll tissue. The center is reddish. Sometimes the lesion is dark green, and the center of the lesion is yellow in the middle. The lower surface of the leaf is also dark green, spotted or lumpy. The surface is slightly elevated, and does not form a similar algae and escort as the green cephalosporin. On the surface cells and appendages of the second lesion, hyphal hyphal cells and green round cells are often seen. (2) Control methods Control algae disease, generally with copper-containing agents such as "." Bordeaux mixture, copper hydroxide and organic copper and other agents have control effect, but the orchard ventilation, moderate pruning, avoid excessive use of Phosphorus fertilizers also have a good effect on the control of algae spot disease in orchards. 6. Fruit Anthracnose (1) Infestation Symptoms Infection with guava Anthracnose, first of all, softened water spots appear on the surface of the fruit, only the mature fruit appears lesions, and the unripe fruit does not; lesions fade or show a brown central black, And there will be a slight inward depression, often spotted pink mucus on black lesions, is an anthrax spore conidia and conidia. Conserved spores often migrate to new shoots, etc., with rainwater, etc., and become infected again. The fruit of anthracnose can be gradually enlarged if it is placed under it. The color of the fruit infected with anthracnose will appear in the central part of the disease, such as pink and lavender, and the diseased external tissues will fade into water stains. (2) Control methods Orchard prevention and treatment of anthrax is generally available with 50% prochloraz (SPC), 50% tetromycin, 40% sterilized Dan, 50% thiophanate WP, etc. , After the application of rain or pruning after the application; in addition, before bagging sterilization must also be applied, before the bagging agent in accordance with the concentration of the first application before the bagging, reduce the damage. China Agricultural Network Editor
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