What are the control methods for sweet osmanthus brown spot disease?
Sweet Osmanthus Brown Spot Disease
Sweet osmanthus brown spot disease is a very common disease; in severe cases it causes the whole plant to drop its leaves, affecting flowering and ornamental value. Aunt Fu, a flower grower in Guiyang and a retiree of the landscaping bureau, told reporters that controlling sweet osmanthus brown spot disease requires a bit of patience.
Sweet osmanthus brown spot disease mainly shows as follows: the pathogen infects the leaves; affected leaves first develop small yellow spots, which gradually turn yellowish-brown to grayish-brown. The spots are nearly round or irregular in shape, or appear as angular spots when their expansion is limited by the leaf veins. Around them is a ring of yellow halo.
In humid weather the diseased areas produce black mold spots, which are the conidiophores and conidia of the pathogen. The sweet osmanthus brown spot pathogen overwinters as mycelium on diseased plants and fallen diseased leaves, becoming the source of primary infection the following year. In late March each year it produces conidia and begins primary infection; the conidia are spread by airflow and raindrops and can invade directly or through wounds and natural openings, with old leaves being more susceptible than young leaves. Brown spot disease occurs from April to October, and the disease subsides after November. High temperature and high humidity favor the disease. Resistance differs among cultivars; generally, Dan Gui is more resistant than Jin Gui and Yin Gui.
How should sweet osmanthus brown spot disease be controlled? Here are some tips:
1. In combination with pruning, remove diseased leaves, clear away fallen leaves on the ground, and burn or deeply bury them in a centralized manner to reduce the source of primary infection. After two consecutive years, results are certain.
2. Strengthen cultivation management; never allow water to accumulate in the soil, and ensure good ventilation and light. Apply more humus fertilizer and potassium fertilizer to improve the plant's disease resistance.
3. During the disease period, spray 1:2:100 lime double-strength Bordeaux mixture, or 50% benomyl wettable powder at 1000-2000 times dilution, or 20% triforine at 500-800 times dilution, or 50% amobam at 1000 times dilution.
There Are Ways to Control Sweet Osmanthus Brown Spot Disease
Sweet Osmanthus Brown Spot Disease
China Landscape Web, October 16 news: Sweet osmanthus brown spot disease is a very common disease; in severe cases it causes the whole plant to drop its leaves, affecting flowering and ornamental value. Aunt Fu, a flower grower in Guiyang and a retiree of the landscaping bureau, told reporters that controlling sweet osmanthus brown spot disease requires a bit of patience.
Sweet osmanthus brown spot disease mainly shows as follows: the pathogen infects the leaves; affected leaves first develop small yellow spots, which gradually turn yellowish-brown to grayish-brown. The spots are nearly round or irregular in shape, or appear as angular spots when their expansion is limited by the leaf veins. Around them is a ring of yellow halo.
In humid weather the diseased areas produce black mold spots, which are the conidiophores and conidia of the pathogen. The sweet osmanthus brown spot pathogen overwinters as mycelium on diseased plants and fallen diseased leaves, becoming the source of primary infection the following year. In late March each year it produces conidia and begins primary infection; the conidia are spread by airflow and raindrops and can invade directly or through wounds and natural openings, with old leaves being more susceptible than young leaves. Brown spot disease occurs from April to October, and the disease subsides after November. High temperature and high humidity favor the disease. Resistance differs among cultivars; generally, Dan Gui is more resistant than Jin Gui and Yin Gui.
How should sweet osmanthus brown spot disease be controlled? Here are some tips:
1. In combination with pruning, remove diseased leaves, clear away fallen leaves on the ground, and burn or deeply bury them in a centralized manner to reduce the source of primary infection. After two consecutive years, results are certain.
2. Strengthen cultivation management; never allow water to accumulate in the soil, and ensure good ventilation and light. Apply more humus fertilizer and potassium fertilizer to improve the plant's disease resistance.
3. During the disease period, spray 1:2:100 lime double-strength Bordeaux mixture, or 50% benomyl wettable powder at 1000-2000 times dilution, or 20% triforine at 500-800 times dilution, or 50% amobam at 1000 times dilution.
Control of Sweet Osmanthus Brown Spot Disease
Sweet osmanthus brown spot disease is a common disease of sweet osmanthus, caused by infection with fungi of the subphylum Deuteromycotina. It occurs in both field-planted and potted sweet osmanthus plants; when it occurs, mild cases affect the ornamental effect, while severe cases cause the plant to die.
Symptoms It mostly occurs on leaves, and in most cases spreads from the leaf tip and leaf margin to the whole leaf. In the early stage the spots are light gray, then expand in an irregular fan shape; later the spots gradually dry up, turn brown, and bear black granular bodies.
Occurrence pattern The pathogen overwinters on diseased plant residues and spreads by wind, rain, watering and other means. In the north, for outdoor care, the disease is most severe from late spring to mid-autumn.
Control methods 1. Promptly remove diseased plant residues; 2. Strengthen water and fertilizer management to enhance the plant's disease resistance; 3. The growing environment should be well ventilated and well lit; do not spray water during the disease period, and avoid rain; 4. Promptly control piercing-sucking pests such as scale insects and aphids; 5. Before bringing plants indoors in late autumn, spray twice with 70% mancozeb wettable powder at 500 times dilution for control; 6. If the disease occurs, control it with 90% chlorothalonil at 500 times dilution or 50% carbendazim at 500 times dilution.