Chrysanthemum
This article introduces knowledge about Chrysanthemum (Jiangxi蜡) from the Flower Clinic, including methods for the prevention and control of diseases and pests, as follows:
Common diseases of chrysanthemum include rust, wilt, and root rot.
1. Chrysanthemum yellowing disease: An important disease of chrysanthemum, affected plants are stunted and shrink, flowers are small and discolored.
(1) Symptoms: Leaves turn light yellow after infection, often growing twisted branches from start to finish. Flowers on the branches have varying degrees of color fading, usually light yellow-green. The plant grows weakly and can continue to infect nearby plants.
(2) Pathogen: Chrysanthemum yellowing disease is caused by MLO (Mycoplasma-like Organism) infection. MLO mainly survives on various perennial hosts, such as daisies, plantains, and天人菊. It is mainly spread by leafhoppers and dodder.
(3) Control methods:
a. The best preventive method is to plant the plant in a net room.
b. Spray 50%马拉硫磷 1000 times liquid or diazinon and other insecticides to control leafhoppers.
c. Regularly clear wild weeds around chrysanthemum to reduce the source of infection.
d. At the early stage of the disease, spray medical tetracycline or terramycin 4000 times liquid.
2. Chrysanthemum gray mold: This disease is a common disease of chrysanthemum, affecting flowers, flower stems, and leaves. In severe cases, flowers and leaves can wither, affecting their ornamental value.
(1) Symptoms: When leaves are affected, they first appear as water-soaked yellow-green or dark green spots, which gradually expand. When the environment is relatively humid, it causes rot and a gray powdery spore layer appears. The affected leaves eventually wither. Petals can be infected in buds or after opening. Initially, the edges of petals appear light brown and water-soaked, and rot occurs similarly.
(2) Pathogen: Botrytis cinerea Pers. of the Botrytis genus.
(3) Infection route: The fungus overwinters in diseased residues or soil. It is prone to occur when the temperature is around 20℃ and humidity is high. Plastic greenhouses are more severely affected than glass greenhouses.
(4) Control methods:
a. Pay attention to greenhouse ventilation, reduce humidity, avoid inappropriate watering. Timely removal of diseased plants and leaves to reduce the source of infection.
b. Spray 50% fast-acting灵 wettable powder 1500 times liquid or 50%扑海因 1500 times liquid during the onset of the disease.
3. Chrysanthemum wilt:
(1) Symptoms: The whole plant becomes wilted and dry. Young plants are affected, leaves become completely wilted. Adult plants show dwarfing, leaves wilt and turn black, and their vascular system also turns brown. Plants in full bloom may suddenly wilt at the top after being affected. The roots of diseased plants show varying degrees of rot, and pink or rose-colored sporulation can be seen at the base of the diseased plants.
(2) Pathogen: Fusarium oxysporum Schl.sp. callistephii(Beach) Snydre & Hansen, belonging to the Deuteromycetes. It is a soil fungus that can survive and persist in diseased plant residues for several years and is spread through seeds and soil.
(3) Control methods:
a. Soak the seeds with 0.1% mercury liquid for 30 minutes to kill the pathogenic bacteria they carry.
b. Rotate the seedling and planting areas or pots every year.
c. Avoid mixing soil carrying pathogenic bacteria into new soil during operations.
d. Soil disinfection: For seedbed soil disinfection, mix 50% carbendazim wettable powder 2 kg per mu with 30 kg of fine dry soil, mix well and evenly sprinkle into the planting holes.
e. Apply medicinal root irrigation or spraying at the early stage of the disease or before the disease occurs.
(1) Use 50% carbendazim wettable powder 500 times, pour 0.25 kg per plant, once every 5-7 days, for 2-3 times consecutively.
(2) Use 40% carbendazim suspension concentrate 400 times liquid, or 50% methyl thiophanate wettable powder 400 times liquid, or 10% double-effect spirit aqueous solution 200-300 times liquid, or 25.9% anti-wilt Ning 500 times liquid.
(3) Agricultural antibiotic "120" 100ppm root irrigation also has a certain control effect.
(4) Pouring potassium permanganate 800-1500 times liquid can also be used for root irrigation.
4. Chrysanthemum rust:
(1) Symptoms: The upper side of the leaves shows chlorotic spots, and the corresponding lower side can see round light yellow powdery sporulation. It is distributed in Jiangsu, Yunnan, Shanghai, and other provinces (cities).
(2) Disease occurrence conditions: When there are alternate hosts such as pine trees near chrysanthemum, it is easy to lead to the occurrence and prevalence of the disease. Pathogen: Coleos porium asterum (Diet)Syd., called aster sheath rust fungus.
(3) Control methods: At the early stage of the disease, spray 15% triadimefon (powder rust Ning) wettable powder 1500 times liquid or 12.5% fast-acting利 3000 times liquid.
5. Chrysanthemum brown spot disease: This disease is a common leaf disease of chrysanthemum, which can cause the leaves to turn yellow and lead to the withering of the whole plant.
(1) Symptoms: Initially, the leaves appear round spots of varying sizes in purple-brown, which later turn black or dark brown. The center of the lesion turns light gray and fine black dots appear. When there are many lesions on the leaves, the whole leaf turns yellow and withers. Generally, it starts from the lower leaves and withers upwards in sequence.
(2) Pathogen: A fungus of the Septoria genus, Septoria chrysan-themella Sacc.
(3) Infection route: The fungus overwinters in mycelium and conidiospore apparatus in diseased plant residues and is spread by wind and rain the following year. In the north, high temperatures and heavy rain in July and August can cause severe disease. Plants that are too dense are prone to disease.
(4) Control methods:
a. Choose a well-drained area for planting. The planting density should be appropriate. Choose disease-resistant varieties. Remove diseased leaves immediately when found. In the fall, collect and destroy diseased leaves and residues in a centralized manner.
b. Spray 50% carbendazim wettable powder 1000 times liquid, or 80% zineb wettable powder 500-700 times liquid, or 1% Bordeaux mixture, or 755 chlorothalonil 500 times liquid for prevention and control. Spray every 7-10 days.
The detailed content of the prevention and control methods for chrysanthemum (Jiangxi蜡) diseases and pests has been shared above, hoping to bring you help!