What are the common pests and diseases of osmanthus trees? This article gives you a detailed introduction
What common pests and diseases affect osmanthus trees? How should they be prevented and controlled? We also ask experienced netizens to help explain. There are many varieties of osmanthus, and four are common: Jingu (golden osmanthus), Yingu (silver osmanthus), Dangui (red osmanthus) and Sijigui (four-season osmanthus). The fruit is a purplish-black drupe, commonly known as guizi.
What common pests and diseases affect osmanthus trees? How should they be prevented and controlled? We also ask experienced netizens to help explainThere are many varieties of osmanthus, and four are common: Jingu (golden osmanthus), Yingu (silver osmanthus), Dangui (red osmanthus) and Sijigui (four-season osmanthus). The fruit is a purplish-black drupe, commonly known as guizi.
Most common osmanthus diseases occur on the leaves, mainly osmanthus brown spot, osmanthus blight spot and osmanthus anthracnose. These diseases can cause early leaf drop in osmanthus, weaken plant vigor, and reduce flower yield and ornamental value. Therefore Zhongdiwang has compiled the damage and control methods for osmanthus brown spot, blight spot and anthracnose, listed in detail below for netizens' reference.
Damage of osmanthus brown spot:
In the early stage of osmanthus brown spot, small chlorotic yellow spots appear on the leaves and gradually expand into nearly round lesions, 2 to 10mm in diameter, or become irregular lesions because the expansion of the lesion is restricted by leaf veins. The lesions are yellowish-brown to grayish-brown, with a yellow halo around the edge. Brown spot generally occurs from April to October, and old leaves are more susceptible than young leaves. The pathogen overwinters as mycelium on fallen diseased leaves, and in the following spring produces conidia for primary infection; the conidia are spread by airflow and raindrops.
Damage of osmanthus blight spot:
The pathogen of osmanthus blight spot mostly invades from the leaf margin and leaf tip, and occurs at the leaf margin and leaf tip. In the early stage of the disease, small light brown spots appear on osmanthus leaves and gradually expand into round or irregular lesions, then enlarge into nearly round or irregular grayish-brown large spots with dark brown edges. Blight spot occurs from July to November, and can occur year-round in greenhouses with poor environmental conditions. The pathogen spreads and infects via conidia carried by wind and water. High temperature, high humidity and poor ventilation favor the disease. When plants are weak, and on old leaves after overwintering and leaves in the lower part of the plant, the disease is more severe.
Damage of osmanthus anthracnose:
This disease infects osmanthus leaves. In the early stage of the disease, small chlorotic spots appear on osmanthus leaves and gradually expand into round, semicircular or oval lesions. The lesions are light brown to grayish-white, with a reddish-brown ring at the edge. Under humid conditions, pale pink viscous acervuli appear on the lesions. Anthracnose occurs from April to June. The pathogen overwinters as acervuli in fallen diseased leaves and is spread by wind and rain.
Control methods for osmanthus diseases:
1. The control of the following diseases first requires reducing sources of infection. For example, thoroughly remove fallen diseased leaves in autumn, and for potted osmanthus, promptly remove diseased leaves.
2. Strengthen the management of osmanthus trees. Choose fertile soil or substrate with good drainage for planting osmanthus; apply more organic fertilizer and potassium fertilizer; the planting density should be appropriate to allow ventilation and light penetration, reduce leaf surface humidity and reduce the occurrence of diseases.
3. In the early stage of the disease, spray 1:2:200 Bordeaux mixture, after which you can spray 50% carbendazim wettable powder 1000 times solution or 50% benlate wettable powder 1000 to 1500 times solution.
4. In severely affected areas, when seedlings leave the nursery, soak them in 1000 times potassium permanganate solution for disinfection.
Control methods for osmanthus tree insect pests:
Generally, the main insect pest of osmanthus is mites, commonly known as red spider mites. Once the disease is found, it should be dealt with immediately. You can use manchongqing, yamansha, and sanzuoxi for foliar spraying. Spray both the front and back of the leaves evenly. Once a week, for 2-3 consecutive times, and it can be cured.
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