The three major diseases of navel oranges are harmful, how to prevent and control the three major di

When it comes to navel orange planting, the more important aspects are water and soil, light and heat, and pest control, and only by grasping these three aspects can we ensure the fruit setting and fruit quality of navel oranges. Yellowing is a common disease that plagues growers, and its impact on navel orange orchards is close to devastating. In addition, the early investment of navel orange orchards is large, resulting in many fruit farmers who want to sell money early and are reluctant to comb the fruit, coupled with the small amount of fertilizer input, the photosynthetic nutrition of the navel orange fruit tree leaves is not enough, so that the roots and leaves get less nutrients, resulting in weak trees and yellowing leaves.

Before the germination of spring buds, after flowering and young fruit stage (late May), each foliar surface was sprayed with borax aqueous solution once, and fruit trees with serious boron deficiency still need to be sprayed twice before the arrival of high temperature in June and August to achieve the correction effect. In order to increase adhesion and prevent pesticide damage, the same amount of lime liquid can be added. Biological organic fertilizer can also be applied in an appropriate amount to create a good growth environment for the root system.

In addition to foliar spraying magnesium fertilizer, the sulfur-based fertilizer of large factories should be selected when fertilizing, and the fertilizers of large manufacturers are generally added with trace elements. I have seen many precedents for citrus seedlings for so many years, but fortunately, they became ill after a few years of hard planting, and the loss was huge! Be sure to ask for the "Plant Quarantine Certificate" when purchasing, fruit farmers can not be greedy for cheap when buying seedlings, enhance professional awareness, change concepts, buy seedlings in places where there is no epidemic, and purchase certified seedlings are indispensable.

Diseased trees cannot absorb nutrients and cannot be treated with drugs**, so prevention can only be the mainstay. Experienced ones will plant fir trees on both sides of the entire orchard to prevent the spread of the virus. In the past two years, fruit trees have been planted by scaffolding, which will be relatively high but can be effectively prevented.

There is yellowing caused by drought or flooding of the roots, and there is also a kind of huanglongbing that navel orange people last want to see. If it is because of huanglongbing, there is basically no way to turn the fruit trees. It can only be removed and burned, and then disinfected and sterilized with quicklime at intervals, and the seedlings can be replanted.

First of all, the plant should be replenished with water, so that one of the hazards can be avoided, and secondly, it should also make some ** places, and also to ensure that the sun's exposure is relatively balanced, followed by some fertilizer, and should also be sprayed with some sterilization or insect control agents.

Be sure to choose varieties that can resist disease, pay attention to scientific management, and fertilize and water on time and in quantity. Do a good job of defense work in advance, and spray pesticides in time when problems are found.

A simple treatment should be carried out for weeds in the field, and timely treatment of pests and diseases should be carried out, so as to ensure that such diseases can be avoided and the yield can be improved.

First of all, when choosing navel orange seeds, choose excellent seeds, choose loose and fertile soil, timely replenish water to oranges, fertilize, and remove pests.

First of all, when planting, we must choose the soil is more fertile and wide land, and when fertilizing, we must choose farmhouse fertilizer, do not use fertilizer bought outside, but also water more often, to prevent the occurrence of pests and diseases, if there is a situation of small insects, then be sure to spray insecticides.

Navel oranges have fruit cracking disease is due to the climate, when the navel orange fruit is about to ripen, the rainfall is relatively heavy, so that the fruit swells too much at once and will crack the fruit.

The control measure is not to water a lot after the navel orange bears fruit, so as not to grow too much at once, and it can prevent fruit splitting disease.

It is because of the climate, or because of excessive precipitation, or because of the high water content in the soil, so that the fruit will crack. If you want to prevent it, you must pay attention to the time of watering, and then control the moisture content of the soil.

This may be due to insect infestation, or it may be caused by overwatering, you should usually pay attention not to water too much, and choose to spray some insecticides to be able to prevent and control.

Symptoms: First the fruit is cracked near the top, then the peel is longitudinally cracked and opened, and the petals are also correspondingly ruptured, revealing the juice cells, some of which are transversely or irregularly cracked, resembling cracked pomegranates, and finally fall off.

It is best to take the disease-free mother tree and disease-free area, soak it with 1000 times tetracycline hydrochloride for an hour before grafting, and then rinse it with water before grafting. The disease is currently transmitted only by the citrus psyllid, the only insect vector, in close proximity, and by scion and seedlings in long distances. Therefore, the prevention and control work mainly does the following points, strictly inspects the vaccine wood, controls the transportation of diseased seedlings and scions, and burns them immediately as soon as the diseased seedlings are found;

Some of the new shoots are yellowed and "yellow shoots" appear, the yellow shoots initially appear at the top of the canopy, and then gradually expand, after 1 or 2 years of the whole plant onset, the spring shoots symptoms mostly appear after the leaves turn green, first at the base of the leaf veins turn yellow, then part of the mesophyll fades green, the leaf veins gradually yellow, the leaves are now irregular yellow-green patches, shortening the tip pulling period. When the new shoots are pumped to 1 2 cm, spray the insecticide 1 2 times. In winter, citrus psyllids prefer to fly to the left of the orchard to overwinter on the bougainvillea.

Spraying insecticides on bougainvillea has a certain effect on reducing the number of psyllids.

In addition, strict quarantine should be implemented for citrus seedlings and scion transferred to the new area. Second, establish a relatively isolated disease-free seedling breeding base. The base must be located in a non-diseased area, and it is required to be free of poison-transmitting insects - psyllids; The rootstock seeds should be harvested from disease-free trees and soaked in 50 52 hot water for 5 minutes, and the leaves of young trees and diseased trees in summer and autumn should be uniformly light yellow-green.

Mottled yellowing leaves. Yellowing begins near the veins, base or edge of the leaf, and then spreads to form uneven patches of yellow and green. Element-deficient yellowing leaves.

It is called mosaic leaves. > it is only the leaves that change at first, but in severe cases, the roots of the fruit tree will begin to rot, and the degree of decay will spread with the disease. Huanglongbing disease starts from the top leaves and then spreads downward, so it can be treated and prevented by daily observation of fruit trees.

First of all, pesticides must be sprayed, and photosynthesis must be carried out more, and more ventilation must be done, and stagnant water must be cleaned up in time.

Usually we must ventilate more, and we must spray more pesticides, and we must choose high-quality varieties, and we must clean up the stagnant water in time.

If you want to prevent and control the physiological diseases of navel oranges, you should apply pesticides regularly and quantitatively to control pests and diseases.

If navel orange has huanglongbing, in the early stage of the disease, spray the treetops of navel orange fruit trees with water amidophos, kill butin, and dimethoate, from April to September, spray 1 pesticide every 1 month to do a good job in the prevention and control of canker disease, the agent can be killed, if red spiders are found, stone sulfur mixture can be sprayed, scale insects can be sprayed with rapid culling, fruit saint, and Spodoptera exigua can be used to prevent and control with hundreds of trees.

A common disease in the cultivation of navel orange trees.

1. Huanglongbing:The disease of huanglongbing in navel oranges is caused by the infestation of rickettsia, the leaves will turn yellow, and the harm of huanglongbing to navel oranges is very great, which will cause the plant to be infected with germs, and will also affect the quality of the navel orange fruit, and even the whole plant will die.

2. Ulcer disease:If canker disease occurs in navel orange orchards, it will lead to a decrease in fruit yield, so it is necessary to adopt agricultural disease prevention and control measures in a timely manner, and the use of corresponding chemical agents can minimize the degree of disease, and the canker disease of navel orange will affect the growth of branches and fruits.

The main insect pest of cultivated navel orange trees.

1. With a rotten stupid red spider:If the navel orange is infested with red spiders, it will affect the growth of leaves, flowers and fruits, and the leaves will be curled, yellow, and defoliated, which will not only affect the growth of navel oranges, but also reduce the yield of navel orange fruits.

2. Scale insects:The common scale insects on navel oranges are chaff scale insects and sagittal tip scale insects, which will affect the growth of leaves, and the leaves will curl and become dry and fall off, if the navel orange fruit is infected, there will be more spots on the surface, and the skin color is not good.

3. Spodoptera exigua:If navel oranges are planted in mountainous areas, chemical control measures should be taken against Spodoptera exigua.

Navel orange tree pest control.

1. Huanglongbing:Do a good job of clearing the garden in winter, reduce the pathogen, in the early stage of the disease, spray the treetops of the navel orange fruit tree with the use of hydroamidophos, kill buty, and oxydimethoate, which can kill the psyllids on the treetops, and eradicate the diseased plants in time once they are found, and the navel orange trees that have suffered from huanglongbing disease can be treated with tetracycline hydrochloride and penicillin.

2. Ulcer disease:From April to September, spray 1 pesticide every 1 month to do a good job in the prevention and treatment of canker disease, and the pesticide can be used to kill, agricultural chain Liyeomycin, Kemycom, Ye Qingshuang.

3. Pests:If you find red spiders, you can spray them in the orchard with stone sulfur mixture, but if you don't master the concentration, it will make the navel orange tree fall seriously, and you can also spray Kemite, Nisolan, imidacloprid, avermectin, scale insects can be sprayed with rapid culling, fruit saint, Lesben, and Spodoptera exigua can be used to control with a hundred trees.

At present, it is the peak period of the occurrence of scale insects, black-thorned whiteflies and leaf rollers, and the prevention and control should be strengthened. Due to the lower temperature than usual, the occurrence of red and yellow spiders is heavier than in previous years, so it is necessary to strengthen the control of red and yellow spiders.

The following high-efficiency, low-toxicity, and residue-free pesticides are recommended:

For the prevention and control of blackthorn whitefly, scale insects and leaf rollers, 48% Lesben emulsifiable concentrate is diluted 800 1000 times; Spray again every 20 days.

For the prevention and control of anthracnose and soot disease, 80% Dasheng m-45 wettable powder is diluted 600 800 times and sprayed, and sprayed again every 15 days; Dasheng M-45 has a special effect on soot disease, and it can effectively remove soot disease by spraying it 3 times in a row.

Red and yellow spiders can be sprayed with mites, i.e. dead emulsifiable concentrate, 1500 times. First of all, we should start from cultivating healthy trees, and appropriately increase nitrogen fertilizer to improve the nutritional level of trees. Secondly, before flowering, the strong and prosperous autumn shoots are pulled into a drooping or horizontal state, so that most of the flowers are facing down when they open, reducing the sun-facing fruit and preventing the production of navel yellow; Again in the early to mid-June to mid-to-late July combined with the fruit, spray 30 40 milligrams of "92O" solution, spray twice, late July to late August with 600 times of "flantin" solution to spray the fruit umbilicus, in order to inhibit the occurrence and spread of umbilical yellow disease.

Common pests and diseases of navel oranges include canker, scab, resin, umbilical yellow disease, red spider, rust tick, leaf miner, scale insects, whiteflies, etc., so in the process of planting navel oranges, it is necessary to do a good job in pest control in advance, and chemical methods can be used to prevent and control them if necessary.

1. Build a park with high standards.

To build a garden on the hillside, we must first build a contour reverse slope terrace, and then open a trench and apply base fertilizers such as straw, pig and cattle pen manure, phosphate fertilizer and lime, and require the amount of base fertilizer under the planting hole of each tree to be not less than 100 kg. The plant spacing is 3 meters, the row spacing is 4 meters, green manure is planted between the rows, and windbreaks and gardens are planted on the main road and the periphery of the orchard.

Second, do a good job in fertilizer and water management.

The amount of basal fertilizer applied to each tree is not less than 75 kg per year. Top dressing of young trees should be applied diligently, once a month from March to August, mainly with fast-acting nitrogen fertilizer, and appropriate application of phosphorus and potassium fertilizer. After entering the fruiting period, heavy fertilization is applied and the frequency is reduced.

From April to May, spray gibberellin or other fruit-preserving elements at a concentration of 50 mg plus potassium dihydrogen phosphate solution to protect flowers and fruits. In July and October, apply fruit fertilizer and fruit picking fertilizer. From July to October, in case of drought or autumn drought, drought prevention and drought resistance measures must be taken in time to ensure that navel orange trees can safely survive the drought period.

3. Reasonable pruning.

pruning of young trees, mainly focusing on shaping, budding and tip control; Fruiting trees should be pruned in summer and winter, eradicate summer shoots in time, leave 5 leaf shorts on the vegetative branches of spring shoots in mid and late July, and retract the strong branches and the mother branches of fallen flowers and fruits to promote the autumn shoots. Due to the strong branching ability of navel orange, the overly dense autumn shoots can be properly thinned at the beginning of winter, and each basal branch leaves 2 4 strong autumn shoots.