Black spot of rhododendron
Rhododendron black spot, also known as brown spot, is a common multiple leaf spot disease of rhododendron. After the disease, the leaves formed black spots, which gradually dried up and fell off until the plant died. The disease mainly harms the leaves of rhododendron, which is infected by Cercospora rhododendron fungi, and several brown spots begin to appear. With the continuous expansion of the spots, the disease spots connect with each other and produce gray-brown fungal hyphae, and the damaged leaves start from the petiole and fall off early from green to brown, which seriously affects the growth, development and ornamental value of rhododendron. The pathogen overwinters on leaves or diseased plants, and the spores spread with the wind.
The recurrence period of the disease is usually in the high temperature and humid season, and the disease occurs in winter in the greenhouse. Generally, plants with weaker growth, seedlings, lower leaves, plants with poor ventilation and rhododendron (compared with rhododendron) have more serious disease. According to the law of the disease, the following prevention and control measures can be taken:
The main results are as follows: (1) to strengthen cultivation and management, rotten leaf soil should be selected in rhododendron cultivation basin soil, pH value of watering should be between 4.5 and 6.5, watering substrate should be dry and wet, and some mature thin organic liquid fertilizer should be often applied to promote plant health, leaf thickening and resistance. Potted cuckoos should be placed in ventilated places and shaded, moisture-proof and water-proof in summer. Diseased leaves should be removed and burned in time, disease-resistant varieties should be selected, and quarantine of plant diseases and insect pests should be strengthened.
(2) Pesticide control: spray 70% topazine wettable powder 800 times or 50% carbendazim 300 times immediately after anthesis. In addition, it can be sprayed regularly, and a mixture of protective fungicides and fungicides can be used, such as Poly Anga M Dasheng 45 and Keshuda alternately, or spraying Bordeaux solution 1-150 Bordeaux solution twice a week; spraying 1-100 Bordeaux solution every 10 days in the rainy season, 3 to 4 times in a row.
- Prev
Hybrid Magnolia leaf blight
The main symptoms occur on the leaves, and in severe cases, they can spread to petioles and buds. The disease spot mostly occurs at the leaf edge, the initial stage is faded green macula, watery, many disease spots are connected into pieces, the fan shape extends outward, the edge is dark brown, and the inside is grayish yellow, which can cause early defoliation. In a humid environment, black-gray grains appear on the fallen leaves. The cause of the disease is a fungal disease; the pathogen lives in the leaf bud and on the remnant of the diseased plant, and by means of airflow transmission, it can be infected directly from the stomata of the leaves with weak growth or physiological injury, and the wind speed is high.
- Next
Control methods of black spot of Magnolia
The main results are as follows: (1) strengthen the nursery management, enhance the tree potential and improve the disease resistance. Select loose, fertile and well-drained soil, apply fully rotten cake fertilizer, loosen the soil and water in time, and pay attention to frost prevention in the north. (2) remove the fallen leaves on the ground in time, cut off the seriously diseased leaves from the trees, and concentrate on burying them deeply. (3) at the initial stage of the disease, spraying 1purl 160 Bordeaux solution or 0.3~0.5Be stone sulfur mixture 77% could kill wettable powder, 30% Wang copper suspension, 25% complex ammonia copper water, 50% bacilli special wettable powder 6.
Related
- Fuxing push coffee new agricultural production and marketing class: lack of small-scale processing plants
- Jujube rice field leisure farm deep ploughing Yilan for five years to create a space for organic food and play
- Nongyu Farm-A trial of organic papaya for brave women with advanced technology
- Four points for attention in the prevention and control of diseases and insect pests of edible fungi
- How to add nutrient solution to Edible Fungi
- Is there any good way to control edible fungus mites?
- Open Inoculation Technology of Edible Fungi
- Is there any clever way to use fertilizer for edible fungus in winter?
- What agents are used to kill the pathogens of edible fungi in the mushroom shed?
- Rapid drying of Edible Fungi