Control methods of Leaf Blight of Rhododendron

Rhododendron, also known as Yingshanhong and pomegranate, is a typical acidic indicator plant in south-central and southwest China. Because the whole plant of rhododendron can be used as medicine, its economic value is very high. If leaf blight occurs in azaleas, it will not only affect the ornamental value of azaleas, but also seriously affect the healthy growth of azaleas.

Rhododendron

First, the main symptoms: occur in the leaves, mostly in the tip of the leaves. In the initial stage, the disease spot is faded green macula, the disease spot spreads inward from the edge, showing an irregular shape; in the later stage, the disease spot is yellowish brown, and when the disease leaf is serious, the disease leaf is dry.

Second, the cause of the disease: fungal diseases. The pathogen lives on the plant disease residue and spreads through watering, insects and human activities. It can occur all the year round in the indoor environment. High temperature, dryness and poor ventilation are easy to cause diseases. The disease is serious after plant growth is weak or suffered by insect pests (especially aphids, shell insects, whitefly).

3. Prevention and control methods:

1. Remove the fallen leaves in time, do not store the fallen leaves in the basin, and burn them centrally.

2. Strengthen maintenance and often spray water to the leaf surface or the surrounding space in order to improve the small environment. Increase the application of phosphorus and potassium fertilizer to enhance plant growth potential.

3. At the initial stage of the disease, 500 Mel 800 times liquid carbendazim or topirazine fungicide was sprayed. If there are pests, it can be sprayed with 1500 times liquid of nicotinine.

Symptoms of prevention and control of rhododendron leaf blight: leaf blight harms rhododendron leaves and causes leaves to fall early. The disease mainly occurs on the old leaves and also harms the young leaves. Most of the diseases occur from the leaf tip or leaf edge, forming irregular leaf margin and leaf tip drying up to 1 leaf 2pm 2 leaf 3 seriously. The disease spot is yellowish brown, the demarcation between the disease part and the healthy part is obvious, the edge color is slightly darker, and the upper black grain spot. Pathogen: the pathogen of leaf blight is Rhododendron Phaeosporium, the black grain spot on the disease spot, that is, the conidium disk of the pathogen. There are conidia in the disk. Occurrence regularity: the bacteria mainly invaded the leaves from the wound. The disease is more serious in plants weakened by insect pests or iron deficiency. Most of the leaves of seriously diseased plants fall off, resulting in weak plant growth, poor development of buds, and even affect the number of buds in the next year. Prevention and control methods: ⑴ timely removal of sick and residual fallen leaves, should not be stored in the basin, should be concentrated burning. ⑵ strengthens maintenance and often sprays water on the leaf surface or surrounding space to improve the small environment. Increase the application of phosphorus and potassium fertilizer to enhance plant growth potential. In the early stage of ⑶, carbendazim or topiramate was sprayed. If there are pests, you can spray 1000-1500 times the liquid of nicotine to control. Control techniques of Leaf Blight of Rhododendron

First, the main symptoms: occur in the leaves, mostly in the tip of the leaves. In the initial stage, the disease spot is faded green macula, the disease spot spreads inward from the edge, showing an irregular shape; in the later stage, the disease spot is yellowish brown, and when the disease leaf is serious, the disease leaf is dry. Second, the cause of the disease: fungal diseases. The pathogen lives on the plant disease residue and spreads through watering, insects and human activities. It can occur all the year round in the indoor environment. High temperature, dryness and poor ventilation are easy to cause diseases. The disease is serious after plant growth is weak or suffered by insect pests (especially aphids, shell insects, whitefly). Third, prevention and control methods: ⑴ timely removal of sick and residual fallen leaves, should not be stored in the basin, should be concentrated burned. ⑵ strengthens maintenance and often sprays water on the leaf surface or surrounding space to improve the small environment. Increase the application of phosphorus and potassium fertilizer to enhance plant growth potential. In the early stage of ⑶, carbendazim or topiramate was sprayed. If there are pests, you can spray 1000-1500 times the liquid of nicotine to control.

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