Prevention and control of mango bituminous coal disease
Harm of mango bituminous coal disease:
The leaves damaged by bituminous coal disease are covered with a loose net of black powdery mildew, which hinders the photosynthesis of leaves. Mildew is limited to leaves, and it is not closely combined with leaves, so it is easy to be erased.
The black mold layer of bituminous coal disease will cover inflorescence, flower spike and lateral branch floret during mango flowering, which will affect the pollination of flower spike and cause the fruit setting rate to decrease. Small fruit is easy to fall off due to the influence of mold layer. In the later stage of fruit growth, the affected pericarp is colored and has poor appearance, which is easy to induce postharvest diseases.
Occurrence time and cause of mango bituminous coal disease;
In areas with obvious spring drought (western Hainan, Leizhou Peninsula in Guangdong, Baise in Guangxi, Yunnan) or in drought years in full fruit, HOMOPTERA insects (flat-billed leafhopper, aphid, scale insect, moth wax cicada, etc. ), insects (thrips) and mites with high population density are rampant. They suck young leaves and young juices and excrete a lot of amino acids, sugars and waxes.
The disease is more serious in orchards with old trees, shady trees and poor cultivation management.
Control method of mango bituminous coal disease
Method 1. Strengthen orchard cultivation management and prune reasonably. Older orchards should shrink their crowns, cut off internal branches, dead branches and insect branches, improve the ventilation and transparency of orchards, and reduce hidden places for leafhoppers, aphids, thrips and mites.
Method two. Regularly control leafhoppers, aphids, thrips and mites.
Method 3: Apply bactericide regularly to inhibit the growth of mold. Spray the tree crown with 800- 1000 times of 75% chlorothalonil wettable powder or 600-800 times of 40% mirex gel suspension, and the application interval is 15-20 days, and it can be applied continuously for 2-3 times.
Control methods of mango anthracnose
Harm of mango anthracnose:
Mango anthracnose mainly harms mango flowers, fruits and shoots. There are many round brown spots on the tender leaves of mango, surrounded by yellow halo, which gradually expand into round, polygonal or irregular brown spots, and then rupture and perforate, and the leaves and young fruits are easily infected by gall midges and leafhoppers.
When mango anthracnose is serious, the tender leaves are easy to bend, the tip and edge of the leaves are often burnt, and the diseased leaves are easy to fall off. The infected branches become black spots and then gradually dry up. Some small spots appear after ear infection, and finally turn black and rot, causing rotten flowers and fruit. Fruit is easy to get sick during the whole growing period. Young fruits will be deformed, blackened and shed after being infected. When larger fruits are damaged, dark brown spots are formed on the peel, the center sinks, and the diseased parts become stiff and degenerate. When the weather is wet, pink sticky substances will grow on the affected parts. This disease not only harms mango in the growth period, but also continues to harm mango during storage and transportation, causing a lot of fruit rot.
Causes of mango anthracnose:
High humidity is the leading factor to induce anthrax, and the relative humidity is above 95%. Keep 12 hours, and bacteria will invade, with an incubation period of 2-4 days. It can happen all year round. All parts of Hainan Province, especially the northeast of Qionghai, can get sick from June 1 1 to April of the following year, when the relative humidity is above 95% and the temperature is 12-30℃. Especially when the temperature is 16-25℃ and the relative humidity is 95%- 100%, anthracnose is most likely to flourish, resulting in crop failure. The pathogen of anthracnose has the characteristics of latent infection, mostly lurking in the peel and pulp near the fruit stalk, or in the mesophyll near the petiole, with a depth of about 65438 0 mm.
Control methods of mango anthracnose;
Method 1: Cut off the diseased leaves of Qingyuan Garden in late autumn and early winter, and burn them centrally. The whole garden was sprayed with Bordeaux mixture of 1: 2: 100 or 1: 100.
Method 2: Pruning and shaping After picking fruits in summer, pruning and shaping should be carried out in time to improve the light transmission and ventilation conditions of plants.
Method 3: Spraying pesticides once a week at flowering stage, and the chemicals are chlorothalonil 600 times solution, carbendazim 500 times solution, thiophanate-methyl 70 times solution, mirex 400 times solution, Spock EC 25% 1000 times solution (bud stage) and copper chloride 20% 600 times solution.
Method 4: spraying 0.2%-0.3% potassium dihydrogen phosphate, urea and borax on the leaves every 7- 10 days; Spraying flower and fruit protective agent for 2-3 times can effectively enhance the disease resistance of plants. Results 70% thiophanate methyl 700 times solution,1:1:bordeaux solution, 75% chlorothalonil 600 times solution, 25% Spock EC 800 times solution and 20% cupric chloride EC 500 times solution were sprayed every half month.
Method 5: After the fruits are harvested, soak them in 70% thiophanate-methyl 1000 times solution (water temperature 52-54℃) 15 minutes, pick them up, put them in a ventilated place to dry, pack them in cartons or bamboo rafts, or move them to low-temperature controlled atmosphere storage for storage; You can also spray 700-800 times of 25% Spock solution on the fruit/0/5 days before picking, and then package it. Spraying medicine once every half a month in the autumn shoot growth period, and the dosage is basically the same as that in the flower and fruit period.
Control of mango weevil disease. Mango leaf-cutting weevils are widely distributed, and adults feed on young mango leaves, resulting in dry leaves; Or female insects lay eggs on young leaves and bite them off from the base, which affects plant growth. Prevention and control methods:
(1) During the growth of shoots, 1 broken leaves were picked from the damaged plants every three days, dried and burned to kill the larvae;
(2) Spraying once every seven days during the shoot growth period, killing with 40% dimethoate EC 1500 times, 90% trichlorfon 1000 times, 25% bisultap 500-800 times and 2.5% fofen 2004-3000 times respectively.
2. Fruit mango weevil and pulp mango weevil The former is a small beetle with a body length of about 7 mm and black. Its larvae eat mango seeds, which affects the fruit quality; Mango weevil with pulp is a small yellow-brown beetle smaller than mango weevil with fruit. Its larvae dive into the pulp, form tunnels, and are filled with insect droppings, making the fruit inedible. These two insects mainly occur in Yunnan, Vietnam, Cambodia and Indonesia, and belong to quarantine objects. However, it is reported that this insect was found in the border areas of Guangxi and Yunnan in recent years. Because these two kinds of insects are serious, but they only occur in local areas, quarantine must be strengthened to prevent them from spreading to new areas. In recent years, it is very dangerous to import a large number of mangoes from Vietnam through non-governmental channels without quarantine.
Prevention and control methods:
(1) Strict quarantine system shall be implemented in areas where the insect has not been found to prevent its spread in new areas;
(2) Do a good job in the orchard sanitation in the pest area, pick up the fallen fruit in time, and concentrate on poisoning;
(3) Weeds should be removed in autumn and winter, and pests overwintering in soil crevices should be carefully plowed;
④ Spraying the mixture of dimethoate trichlorfon and water 1: 1500/time every 7- 10 days in the young fruit stage 30-45 days after flowering, and the control effect is obvious for 3-4 times in a row.