Anthrax can damage the leaves of Magnolia grandiflora, first of all, the leaves or old leaves, from the tip and edge of the leaves began to attack. In the early stage of anthrax, there will be irregular spots, which will gradually expand and even spread to a quarter of the whole leaf.
Anthrax is more serious in rainy and humid weather.
At the beginning of anthrax, 1:1:100 times of Bordeaux solution can be sprayed for prevention and treatment.
The leaf spot of Magnolia grandiflora occurred. In the early stage, the spot was brown round spot, which was expanding continuously. The whole spot was gray white inside and red brown outside. In the late stage of leaf spot disease, the spot will dry up and grow black particles.
Under the condition of rain and high temperature drying, Magnolia grandiflora is prone to leaf spot disease.
Prevention and control of leaf spot disease, one is to timely remove the remains of the disease and regularly burn the dead branches of the disease; the other is to spray carbendazim, methyltobuzin and other fungicides regularly for sterilization.
Paramecium usually occurs in two generations a year. July and September are its peak periods. Most of the Paramecium are parasitic on the axils, shoots, leaves and branches, which do great harm.
The first and second ten days of April and the middle and last ten days of August are the suitable time for the control of Paramecium. The medicament of prevention and cure can choose the medicament such as Hua Bao, fat insect line..
Magnolia grandiflora in May, late June to August this period of time, is Taiwan's milk termite peak.
To prevent and control Taiwan's milk termites, one is to place "Yike" and other traps in the ant path; the other is to avoid the mechanical damage of trees; the third is to strengthen the maintenance management and timely fill holes for trees.
Dry rot usually occurs on the 1-2-year-old branches and stems of Magnolia grandiflora. At the beginning of the disease, the cortex will become soft and fall off. With the development of the disease, the epidermis of Magnolia grandiflora will gradually dry, and the subcutaneous part will become dark brown, and grow black dots.
When cultivating Magnolia grandiflora, we should pay attention to the protection of the wound when pruning the branches. We can apply the protective agent. Dry rot disease, can be coated with 70% tobujin 800 times liquid for control.
The damage of Alternaria alternata gray spot is still very big. In the late stage of the disease, the edge of the spot is black, the center is white to gray white, and the black mould cluster will gradually expand.
For this kind of disease, first, it is necessary to timely remove the remains and bury or burn them; second, at the early stage of the disease, it is possible to spray 600 times of 75% chlorothalonil wettable powder for prevention and control, once every 10 days or so, generally 3-4 times.
Spot disease is a common disease of Magnolia grandiflora. The disease is that there will be small round spots on the leaves, which are yellow or light brown. The spots will gradually expand, and black small particles will grow later. When the damage is serious, it will cause the leaves to fall.
The first is to cut off the diseased leaves in time, and collect the diseased leaves to bury or burn them intensively, so as to reduce the primary infection source; the second is to spray 500 times of 20% Longke bacteria suspension for prevention and control in the early stage of the disease.
