There are two
Common types of banana leaf spot, yellow spot and black spot. In the past two years, there have been frequent occurrences in banana gardens, and the damaged area of ​​banana leaves often accounts for 20% to 40% of the total area of ​​the leaves, and in severe cases it is more than 80%. Most of the leaves of the diseased plants are dry and dead, and the plants are unable to plant heads and fruit, or can When the fruit finger is smaller, the yield is greatly reduced, and the quality of the fruit is reduced. In severe cases, the yield can be reduced by more than 50%. First, the disease yellow leaf spot disease at the beginning of the disease is the top of the third or fourth leaf on the top of the plant appearance of small yellow-green stains, sick lines and veins parallel to the vertical expansion, the formation of yellow-green or yellow stripes, and then stripes again The formation of dark patches expands to appear water-stained, the center becomes brown or rust-red, and the edges are surrounded by yellow halos, after which the central tissue of the patches or stripes is dry. When the disease is severe, multiple lesions or stripes merge into each other and the surrounding tissues become necrotic. The large areas of the leaves turn black and dry and quickly die. Black leaf spot initially appeared between the veins on the underside of the fully expanded third or fourth leaf, with tiny faded green spots. Spots grow into rust-brown stripes and then darken, becoming dark red, brown, or black. Severely damaged leaves, lesions, or fringes merge, causing large areas of mesophyll tissue to be destroyed, becoming black and water-stained, and finally diseased leaves quickly die, dry, droop, and hang upside down on pseudostems. Leaf spot is a fungal disease and it is prone to develop in high-temperature and high-humidity weather conditions. Especially after a typhoon, the leaves cause more wounds and the disease is more serious. The occurrence of dense planting, non-removal of buds, poor drainage of soil, overgrown weeds in the plantation area, poor management, partial application of nitrogenous fertilizer, and bad ventilation conditions are the most common problems. Second, the prevention and control methods 1, to strengthen fertilizer and water management: increase organic fertilizer and phosphorus and potassium fertilizer, to avoid partial nitrogen fertilizer, promote plant growth robust. At the same time, when the new banana leaves are extracted and unfolded, the roots are sprayed with nucleotides, gaomeishi, spray-applied or potassium dihydrogen phosphate to enhance the tree vigor and increase its resistance to disease. 2, pay attention to the banana garden care: timely digging through irrigation drainage canal valley, so that can discharge irrigation; clear weeds in the garden, remove excess sucker, reduce the humidity of the banana garden, keep the surface dry and moist, in order to facilitate growth, reduce Onset. 3, clear leaves and dead leaves: on the incidence of heavy plants, timely removal of the plants on the seriously illused leaves and dead leaves, remove the ground sick leaves, move out of the park to burn, reduce the bacteria source, make the orchard air and light, reduce humidity , mitigate harm. 4, timely spraying control: in the early stages of disease, after clearing the diseased leaves and after a heavy storm, timely medication control, spray every 7 to 10 days 1, continuous spray 3 times. Control agent can choose 64% of antiviral 800 times, 70% of mancozeb 700 times, 77% can kill 1000 times, 25% must shake 1000 times, etc., the above drugs should be used alternately to avoid color Drug resistance, improve control efficiency.
Common
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