The latest course on cultivation techniques and methods of avocado

Avocado is a kind of rare fruit in the tropics, also known as avocado, etc., the fruit is a kind of fruit with high nutritional value, which contains a variety of vitamins, rich fat and protein. The contents of sodium, potassium, magnesium and calcium are also high. Besides being used for fruit consumption, it can also be used as dishes and cans, which is of high cultivation value. Let's take a look at the cultivation techniques of avocado.

Cultivation conditions of avocado

Avocado likes light, warm and humid climate, and is not resistant to cold. Only a few varieties can endure a short-term low temperature of 0 degrees Celsius. It is cultivated at 40 °S ~ 40 °N in the world, with an average annual temperature of 20: 25 ℃. Cold resistance varies with different varieties (strong cold tolerance of Mexican line, weak cold tolerance of Guatemala and West Indies), cold-resistant varieties can tolerate-6 ℃ low temperature, low cold resistance varieties will dry up when low temperature is 0 ℃. Need annual rainfall of more than 1000 mm, shallow roots, fragile branches, can not withstand strong winds, strong winds can lead to reduced production, strong adaptability to the soil.

Propagation methods of avocado

Avocado can be propagated by seed or grafting. When sowing, the seed coat should be peeled off and germinated in the sand bed. The plant should be planted in a place with deep soil layer, good drainage and shelter from the wind. The suitable row spacing is 5 * (6-7) meters, and mixed planting of varieties can ensure pollination. It is best to raise seedlings in containers. The seedlings can be grafted by bud grafting or abdominal grafting with a diameter of 0.8 cm. The seedlings can be planted at 50 cm or 60 cm. The row spacing of the plants is 5 cm. The grafted seedlings will blossom and bear fruit for 3-4 years or 4-6 years. The mature trees can produce 25-50 kg and the high yield 100-150 kg.

Fertilization technology of avocado

The main results are as follows: 1. nitrogen fertilizer is routinely applied more than 4 times a year, usually by withdrawal or through irrigation system. 50 kg organic fertilizer per plant and 50 g compound fertilizer are applied to adult trees in young fruit stage, and the quantity is doubled after harvest.

2. When the leaf analysis indicates that phosphorus and potassium fertilizer is applied when the content of phosphorus and potassium is low, zinc can be applied or foliar spraying zinc in some types of soil, and spraying is the most effective when new leaves are developed in spring. the most effective way for crops to grow on calcareous soil or soil with low oxygen content is to inject chelating iron solution into the root zone.

3. The amount of nitrogen used should be reduced when there is nitrogen in some soil and irrigation water, and nitrogen fertilizer should be applied when there are few new leaves growing on trees and when the leaves are gray or bear much fruit.

Control of diseases and insect pests in avocado

1. Anthrax

Anthracnose is an important disease of avocado, which mainly harms mature fruit, and can also infect leaves, twigs, flowers and young fruits, cause fruit drop and fruit rot, and shorten shelf life. Generally, the disease occurs after fruit ripening, and the diameter of the spot before ripening is not more than 5 mm, round, slightly sunken, brown or black. When the conditions are suitable, the disease spot expands rapidly, the depression is obvious, the center of the disease spot appears radiant cracking, and finally the disease spot is connected, and the pink conidia pile appears. As the fruit ripens gradually, pathogens can invade the pulp, causing black-green dry rot.

[control] remove the diseased branches in the orchard, cut off the diseased leaves, eliminate the source of infection, and carry out low-temperature pretreatment and low-temperature storage as soon as possible after harvest. Almost all avocado varieties are sensitive to the pathogen of the pathogen. The key to control is to minimize the occurrence of other fruit diseases (especially tail spot disease) and avoid mechanical damage in fruit transportation.

2. Scab

[harm] the damaged fruit produced a slight round brown scar at the beginning, and then turned brown to light purple. After fruit ripening, the disease spot was United, the center was sunken, and the pericarp was rough. After infecting the fruit, the disease did not affect the flavor quality, but the appearance quality decreased seriously. In the young fruit stage, if the weather is cold and wet, the disease occurs seriously. It can also damage the leaves, the damaged leaves appear brown spots, the leaves wrinkle, the disease spots further develop into a star shape, and the center is perforated. Leaf damage often occurs at the top of the crown, and the disease spot is mostly in the leaf back texture, the disease spot is small, discrete and discontinuous, and it is not easy to observe. The petiole and branchlet disease spots are oval and are easily confused with the spots caused by shell insects.

[prevention and treatment] cut off the diseased branches to reduce pathogens and spray Bordeaux solution or other copper preparations.

3. Cercospora spot disease

[harm] can be harmful to leaves, stems and fruits. Infect the fruit, form withered spots on its surface or cause epidermis cracking, cracks can cause anthrax infection. When infecting the leaves, the withered spots of 2 to 5 mm appeared on the leaf surface at first, the first brown, then turned purple, the spots extended to both sides of the leaves, the shape was irregular, and when serious, the withered spots joined together to form larger withered spots.

Using chemical control, copper preparation and azoxystrobin were sprayed on branches and fruits.

4. Fruit rot of small cave shell

[harm] the symptoms of infected fruits were not obvious before picking, and the disease spots were small and shallow, and the symptoms became obvious in the process of fruit harvest and softening. Small and irregular brown to red disease spots appeared in the initial pericarp. Due to the bacteria invading the vascular bundles, brown stripes could be seen in the pulp after peeling off, and then purple-brown irregular disease spots appeared in the pedicel. With the ripening of the fruit, the epidermal spots gradually grow, blacken and sunken, and the brown pericarp is covered with grayish-brown mycelium and spores, which exudes brown pulp and juice and gives off a bad smell.

[control] cut off dead branches and tips, remove dead trees and diseased fruits, choose sunny weather to harvest fruit, strengthen nutrition of fruit trees and reduce the occurrence of other diseases.

5. Pedicle rot

[harm] the pedicel was first susceptible to disease, and slightly withered around the pedicel. With the fruit ripening, the bacteria invaded the fruit, and there was obvious black rot around the pedicel, and the disease boundary was obvious. And gradually spread to the whole fruit surface, the bacteria invaded the pulp, causing tissue discoloration, degradation, and emitting an unpleasant smell, thus reducing the fruit quality.

[prevention and treatment] the pathogen can survive on the host disease residue. Therefore, it is necessary to eliminate the source of infection in time to avoid the accumulation of diseases and disabilities in the park. Watering the lower part of the orchard can prevent the germs from moving to the higher fruit. Eliminating water stress can reduce infection. Covering with film or weeds under the tree can accelerate the decomposition of the diseased body. In addition, do not harvest in cloudy and rainy days.

6. Phytophthora fruit rot

[harm] Phytophthora can cause fruit rot, stem ulcer and rot both before and after harvest. Black round disease spots often appear near the pedicle of susceptible fruit, and the pathogen can invade the pulp.

[prevention and treatment] cut off the withered branches and stems, clean up the orchard, remove the fallen fruit and diseased fruit, and prevent the re-infection of the pathogen. Cover with thick mulch under the plant to inhibit the spread of bacteria in the soil.

7. Soot disease

The surfaces of fruits, leaves and stems are covered with a large number of black soot-like hyphae and spores and grow on honeydew secreted by wax scale and whitefly.

The key is to control pests and reduce honeydew production. A better method is to use natural enemies for biological control.