Pest control of Yulinglong

Pest control. Osmanthus fragrans is prone to anthracnose, brown spot disease, plaster disease, Fusarium wilt, algae spot disease, soot disease, whitefly, scale insect, moth, thorn moth, grasshopper, osmanthus leafhopper and other pests, which need to be sprayed in time for control. Brown spot is caused by fungi, which harm leaves. At first it was yellow spots, and later it developed into nearly round or irregular spots, yellow-brown to taupe. The diameter of the spot is 2- 10mm, the outer edge of the spot has yellow halo, and many black mildew spots are scattered on the front of the leaf. These are conidia and conidia of fungi. After the diseased spots become large spots, the leaves will die, but they will not spread to the veins. Pathogens are spread by wind, rain, water and other means. It began to increase in March, and from April to the onset of 10, and the incidence decreased after 10. High temperature and high humidity are beneficial to the disease, and the disease of old leaves is more serious. Generally speaking, Dangui is more resistant to the disease than Jingui and Yin Gui.

Prevention and control methods: remove the remains and leaves of diseased plants in winter and destroy them in time. The introduced seedlings should be pruned of diseased leaves. When the seedlings in seriously ill areas leave the nursery, potassium permanganate can be sprayed 1000 times. Chemical control refers to osmanthus leaf blight. Strengthen the management of water and fertilizer, increase the application of humus fertilizer and potassium fertilizer to enhance the disease resistance of plants; The environment should be ventilated and transparent, and do not spray drugs during the onset period to avoid getting wet in the rain. Never accumulate water in the soil. Timely control sucking pests such as scale insects and aphids; Spray 70% mancozeb wettable powder 500 times twice before entering the house in late autumn. If it happens, it can be prevented with 500 times solution of 90% chlorothalonil or 500 times solution of 50% carbendazim. During the onset period, you can spray 1: 2: 100-200 times of lime Bordeaux solution, or 1000- 1500 times of 50% benlet wettable powder, or 500 times of amobam, or 600 times of 50% amobam solution. Leaf blight, also called leaf blight, is an important disease of osmanthus fragrans. The damage of leaves mostly starts from the tip and edge of leaves, and the small spots are light brown, and then expand into round or irregular shapes. Lesions are sometimes friable and curly. Lesions can be interconnected to 1/3 to 1/2 of leaves. They are grayish brown with green edges, and small black spots are produced on the later lesions. The disease can occur all year round, resulting in large-scale dry leaves, high temperature and humidity, poor ventilation and weak plant growth. It usually occurs from July to 1 1, and it is spread by wind and rain.

Prevention and control methods: thoroughly remove diseased leaves in late autumn and early winter, burn or bury them centrally, and reduce overwintering bacteria, which can effectively inhibit the occurrence of diseases in the coming year; Transplanted or introduced seedlings should be removed from diseased leaves and burned centrally. When necessary, the seedlings can be disinfected by spraying 500 times of 50% carbendazim wettable powder or 0. 1% potassium permanganate solution before leaving the nursery. Strengthen management, increase the application of phosphorus and potassium fertilizer, often loosen the soil and weed, prevent soil hardening or water accumulation, water and spray water in time in case of high temperature and dry weather, and increase the disease resistance of osmanthus plants; Spraying 500 times solution of 70% mancozeb wettable powder, 800 times solution of 75% chlorothalonil wettable powder or 1: 2: 100 lime bordeaux solution once every half month for 3-4 times continuously has good control effect; It can also be sprayed with 5000 times of 25% propiconazole EC at intervals of 48 days. The disease usually occurs in hot and humid seasons and in hot and humid, hidden and poorly ventilated environments. The main performance is that leaves and branches are covered with a layer of gray-black powder of different colors, and sometimes even a black film is formed. The reason is that when aphids, scale insects, whiteflies and other insects harm osmanthus fragrans, the excreta secreted by them cause parasitism of many fungi, thus inducing a dark gray sooty blotch. The gray-black coal pollution layer not only affects the ornamental of osmanthus fragrans plants, but also affects the photosynthesis of leaves, resulting in poor plant growth and early shedding of susceptible leaves after yellowing and wilting.

Prevention and control methods: strengthen the shaping and pruning of osmanthus plants, ensure the ventilation and light transmission in the plant cavity, and promote the good growth of plants; When aphids, scale insects, whiteflies and other pests are found to harm osmanthus fragrans, effective prevention and control should be carried out in time to kill them; Potted plants, often spraying water to wash leaves; At the initial stage of the disease, spraying branches and leaves with 500 times of 50% methyl sulfide suspension, 800 times of 50% carbendazim wettable powder or 500 times of 75% chlorothalonil wettable powder has a good control effect. This disease is iron deficiency chlorosis. Due to the imbalance of PH value in soil, alkaline soil and incomplete cleaning of building residues, iron in soil exists in the form of insoluble iron hydroxide, which cannot be absorbed by osmanthus fragrans roots, thus making osmanthus fragrans lack of iron. If it is mild iron deficiency, it means that the veins of young leaves turn green and yellow, and the vein tissue is still green; If the iron deficiency is serious, the new and old leaves will turn yellow, the young leaves will stop growing slowly, some old leaves will appear yellow-brown spots, and the plants will not grow and bloom normally, which will seriously affect the ornamental effect and the harvest of flowers.

Prevention and treatment methods: mild iron deficiency can be treated by pouring 0.5% ferrous sulfate solution on roots and spraying 0.2% ferrous sulfate solution on leaves; When iron deficiency is serious, 20-40g chelating iron [F-EDTA] can be applied to the soil around the rhizosphere of each osmanthus fragrans (including potted osmanthus fragrans), and 0. 1% chelating iron solution can be sprayed on the leaves at the same time; Spraying leaves with 0.2% ferrous sulfate solution every half month during the growth season of new shoots in spring; When preparing potted soil, the pH value can be adjusted to below 6.5 with 0.5% ferrous sulfate solution. It mainly occurs on newly transplanted osmanthus plants with large specifications. When landscaping or transplanting osmanthus fragrans, the trunk or branch bark of osmanthus fragrans plants is seriously damaged or large pieces of dry bark are not properly protected in time due to reasons such as bumps during digging, scratches during long-distance transportation and strangulation during hanging planting. When rain and sewage infect wounds, fungi (such as wood rot fungi, etc. ) and bacteria (such as soil wild Bacillus, etc. ) is induced to invade and parasitize, causing the wound to rot.

Prevention and treatment methods: for small wounds on tree trunks or branches, wound healing agents should be applied in time; For small wounds that have been partially decomposed or slightly decomposed, the wound can be partially cleaned until the fresh xylem and phloem are exposed, and then the wound healing agent can be applied to the fresh wound to promote the wound healing as soon as possible; For old big wounds with long-term phloem damage and exposed xylem for many years, the rotten exposed xylem can be cleaned up, and the stone sulfur mixture can be applied regularly every year to prevent corrosion, or it can be quickly applied to fresh wounds after being colored with two-component marble glue, which will have better protection effect; For the thick osmanthus plants with cavities in the trunk, the rotten parts can be thoroughly removed first, and the isolation layer between rotten xylem and non-rotten xylem should not be destroyed, and the cavities should be filled with polyurethane foaming agent.