Hurry, what should we do if many of our apple trees here are starting to lose their leaves?

The causes of early defoliation of apple trees are: pests and diseases, poor light in the inner chamber; Sudden heavy rain in dry and hot weather in summer; Lack of nutrients in the tree, among which pests and diseases are the most severe. If no control measures are taken, the leaves will begin to fall in mid-July, and most of the leaves will fall off in August, weakening the tree, affecting the formation of flower buds, and may cause secondary flowering and leaf development in autumn, causing serious economic losses.

1. Prevention of early defoliation caused by fungi. July to August is the peak period of brown spot disease, gray spot disease, and ring pattern disease. Brown spot disease:

The lesions on the leaves are nearly round, black-brown, with black dots, vaguely arranged in the shape of concentric rings, and some are needle-shaped. The lesions are green around and the outward leaves are yellowish. Gray Spot Disease:

The lesions are round, with well-defined, sunken, purplish-brown lesions. The lesion is brown at first, then silvery-gray. Ring disease:

Mostly scattered on the leaf margins, semicircular, brown, with interlaced concentric wheel patterns. The main fungicides used: 80% Dasheng M-45 wettable powder 800 times; 500-800 times of 27% copper noble disparity float; 200 times of 1% Zhongshengmycin aqueous solution, etc., spray once in 15-20 days, and spray four or five times in a row.

From late August to early September, spray 160 times the amount of Bordeaux liquid, low-lying, foggy, and unventilated apple orchards, and later use 50% carbendazim 500 times liquid spraying.

2. When the insects such as apple tumor aphid, cotton aphid and red spider are seriously damaged, they can cause early defoliation. Aphids: Adult aphids and nymphs swarm on the swollen buds, young shoots, and young fruits to suck the sap, and the heavily damaged leaves roll backwards, shrink and dry up.

Spider mites: Juvenile, nymphatic and male adult mites are mostly active on the back of the leaf, and female adult mites are mostly active on the front of the leaf. Generally, there is no habit of spinning silk and forming nets, and when the number of mites is high, adult mites can spin silk and droop and drift away with the wind.

From late July to early August, fruit trees are infested by leaf mites, which have the greatest impact on yield, quality and flower buds of the following year. For the control of aphids, you can choose: 50% anti-aphid wettable powder 2000-3000 times, high-efficiency cypermethrin EC 3000 times, 10% nicotine EC 800-1000 times, etc.

For the prevention and control of red spiders, use: 73% Gram Mite EC 1000 times, 5% Nisolan EC 2000 times, 15% pyridoxine EC 3000 times, etc.

It is necessary to distinguish between different situations, drought, waterlogging, leaf spot disease, or pesticide damage and fertilizer damage. The measures taken vary depending on the situation.

Is it not good for the root system to absorb the leaves now? Or are there too many apples to drop the fruit trees? This is a specific problem to be analyzed, do you look at the yellowing of the leaves or something else?

1. Infection with viruses.

Brown spot is a major cause of defoliation in apple trees. When apple leaves are infected with a germ, the leaves will produce brown spots, and if multiple spots appear on the same leaf at the same time, the leaves will turn yellow and fall off before the lesions grow. You can use 500 times of 70% mancozeb wettable powder, spray once every half month, a total of 3 4 times.

2. Improper management.

Inadequate management of the orchard and poor growing environment lead to defoliation. In winter, the old, weak, sick and stump branches are not pruned in time, so that the fruit trees carry a large number of pests and diseases into the winter, and the cleaning of the orchard is not thorough. If you want fruit trees to grow well, you must strengthen management, clean up pests and diseases in time, and spray drugs.

3. Planting environment.

Apple trees should grow in a relatively open place on high ground, if the growth environment is closed, the ventilation and lighting are poor, it is not conducive to the growth of apple trees. Apple trees love light and should have plenty of light. It is suitable for growing in sandy soil with deep soil layer and good drainage.

If the growing conditions are too poor, it will affect the growth of fruit trees.

Rational fertilization: increase the application of phosphorus fertilizer and potassium fertilizer, avoid partial application of nitrogen fertilizer, and improve the disease resistance of the tree. Pruning and leaf pruning:

In July, prune the long branches and diseased shoots, and remove the residual branches and leaves in late autumn and early winter. Pesticide prevention and control: use Liangguoan, wofengsu and other agents to spray apple trees regularly.

Precautions: Reasonable spraying of Chinese herbal preparations to prevent other diseases.

1. Reasonable fertilization

At this time, the fallen leaves in the ground should be cleaned up immediately, pay attention to orchard hygiene, and then apply more organic fertilizer, increase phosphorus and potassium fertilizer, avoid partial application of nitrogen fertilizer, and improve the disease resistance of the tree.

2. Pruning and leaf pruning

When the apple leaves are serious, it should be pruned scientifically, increase the ventilation and light transmission inside the tree, especially in July every year, to cut off the long branches and diseased tips in time, remove the residual branches and leaves in late autumn and early winter and burn them intensively, and thoroughly do a good job of clearing the garden.

3. Pharmaceutical prevention and control

After the apple is infected with spotted defoliation, there will also be serious defoliation, which can be sprayed regularly with agents such as Liangguoan, garlic oil, and wofengsu during the fruit growth period, and after fruit picking and leaf fall in autumn 2 3, it is evenly sprayed with ulcer rot in the winter garden clearing stage.

4. Precautions

In addition to being infected with defoliation, apple trees will lose their leaves, if they are attacked by brown spot, wheel spot, gray spot and other diseases, they will also fall leaves, so we should pay attention to the spraying of Chinese herbal medicines, which can not only kill bacteria, but also increase the chlorophyll content in the leaves and improve the autotrophic function of the tree.

Apple spotted defoliation is a fungal hazard that can overwinter on fallen leaves and spread by wind and rain the following year. The incubation period of pathogenic bacteria is short, generally 1-2 days, and a large number of defoliation can be caused by two peak damage peaks (peak defoliation) in spring (early May to mid-June) and autumn (August to September) every year. So how to prevent and control defoliation?

1. Strengthen cultivation management. Pay attention to orchard hygiene, apply more organic fertilizer, increase phosphorus fertilizer and potassium fertilizer, avoid partial application of nitrogen fertilizer, and improve the disease resistance of trees; Reasonable pruning, especially in July, to cut off long branches and diseased shoots in time to improve ventilation and light transmission conditions; Timely tillage can eliminate the stagnant water at the bottom of the tree and reduce the humidity of the orchard, which can reduce the occurrence of diseases to a certain extent. In late autumn and early winter, prune the diseased branches, clean up the residual branches and fallen leaves, concentrate on burning, and use the spray of the decay to thoroughly clean the garden to reduce the source of initial infection.

2. Pharmaceutical prevention and control. In order to prevent the occurrence of early defoliation disease in apple tree spots, you can use Liangguoan, garlic oil, and wofeng for regular spraying during the fruit growth period; After fruit picking in autumn, after falling leaves 2 3, and in the winter garden clearing stage, the use of ulcer rot and wofengsu spray, not only can play a role in sterilization, effectively prevent the occurrence of spot defoliation, but also supplement the tree with fulvic acid, amino acids, polysaccharides, trace elements and other nutrients, the product contains Houttuynia cordata, berberine and other substances can also accelerate the healing of wounds, especially in typhoons, rainstorms and other bad weather spraying has a good bactericidal effect, reduce the number of pathogenic bacteria, but also quickly promote cells, Tissue restoration.

If the fruit tree itself is too abundant, it will produce the condition of fruit loss, and the key factors are as follows: due to poor watering, due to too much basal fertilizer, and less fertilizer, the fertilizer is very unbalanced, which leads to the carbon and nitrogen balance in the fruit tree is removed, and nutrient overflow will occur, and the growth imbalance of the reproductive system will occur, and it will adjust itself and produce a lot of fruit drop.

In the past, when there was little blooming during the flowering period and the conclusion was very small, the fertilizer effect was very high, the nutrients were too much, and there was no supply from the region, so the conclusion will be made again according to the method of fruit dropping. It is caused by insect infestation, so we must pay attention to the observation and pick up the fallen fruit to see if there is a condition of course rotten, which is very different from the outbreak of a fall and rotten. It is also possible that the stem of the tree has developed diseases such as ring pattern disease, and it may also cause fruit drop.

The standing apple tree branches change direction according to the method of bracing and pulling, so that the branches are scattered, which can improve the air circulation and light transmittance of the apple tree, can inhibit the rapid growth of the branches, and make the iPhone grow stronger during the fruiting period.

Extremely heavy topping can effectively reduce the consumption of nutrients, so that nutrients accumulate on the early growing strips, thereby accelerating the growth of veraison and preventing fruit drop due to insufficient nutrition.

It is not necessary to promote the growth of plant type during the flowering and fruiting period, but to slowly reduce ammonia fertilizer, increase the total amount of phosphorus and potassium fertilizer, and pay attention to watering, which can increase the fruit size.

Every 7 to 10 days after the veraison phase, the leaves are sprayed with carbohydrates, soil or other trace element fertilizers. The sprayer should be delicate, well-proportioned and thoughtful. The actual effect of leaf fertilizer is remarkable, but after all, the fertility is relatively limited, and it is only an auxiliary countermeasure, which cannot replace the fertilizer on the soil layer.

The actual effect of spraying naphthalene acetic acid or other anti-falling hormone is significant in promoting fruit hanging and reducing physiological fruit drop. It must be noted that the instructions for use should be strictly followed to indicate the concentration value, and the amount of use should not be increased or decreased arbitrarily.

The cause of fruit drop in apple trees is: natural fruit drop, generally apple trees naturally drop fruit twice; Excessive tree vigor apple trees are prone to fruit loss due to improper fertilizer use, resulting in an imbalance in the proportion of carbon and nitrogen in the tree; The common diseases of apple trees caused by pests and diseases are trunk rot and fruit rot, and the common ones are rot disease, ring pattern disease, anthracnose, etc. How to drop the fruit of the apple tree:

The branches of the apple tree are bracketed and pulled to change the growth direction, so that the branches are dispersed, and the branches are ventilated and transmitted. Proper topping can effectively reduce nutrient consumption, thereby accelerating the growth of young fruits and avoiding fruit drop caused by insufficient nutrients. At the apple blossom and fruit stage, it is necessary to reduce ammonia fertilizer and increase nitrogen, phosphorus and potassium fertilizer, and pay less attention to it, which can promote fruit expansion.

The hanging fruit of the apple tree is silver, the apple is ripe, and the so-called melon is ripe and falls, so the apple falls off the tree, is absorbed by the soil, and then is absorbed by the roots, resulting in the continued growth of the second year.

The reason for the fruit loss of apple trees may be improper fertilization, we need to carry out topdressing in time, or it may be caused by pests and diseases, which is to spray pesticides in time.

Early apple defoliation may be brown spot, gray spot, spotted defoliation, wheel spot, and round spot. It has been a few years since the onset of the disease and it is not easy until now**. It is recommended to start spraying the trunk and soil with a 10,000 times solution of Pythium oligoandrogens during wintering this year, and use it until the next year, once every 3 weeks, which can be prevented.

Increase the dose of prevention and control before the outbreak of the disease in the coming year.

It may also be caused by drug damage. See whether the formula has been adjusted in the pesticides used in the past few years, and if the analysis is caused by this formula (such as a zinc-containing formula), change the dressing immediately.

After flowering, before bagging, 4 times in mid-July and mid-to-late August to ensure that the leaves do not fall.

It may be a fungal disease: brown spot or spotted defoliation.

Brown spot disease: This disease mainly affects leaves, but can also infect fruits and petioles. Generally, the leaves and fruits of the lower part of the canopy and the inner chamber are the first to be affected.

At the beginning of the disease, the leaves appear black-brown vesicles or needle-like dark brown lesions, the edges are not neat, the boundary between disease and health is not clear, and the diseased leaves turn yellow and fall off in the later stage, but the lesions still remain green around them, and there are black-brown needle-like lines and fly fecal-like black spots on the surface of the lesions. It takes about 13 55 days from the invasion to the defoliation, and the field begins in May and June, enters the peak period in July and August, and stops expanding in October.

Apple spotted defoliation: It is caused by the infection of semi-intellectuals among fungi. Among them, spotted defoliation is a virulent strain of apple wheel spot.

It can occur without a wound and is extremely pathogenic. The pathogen of apple spotted defoliation disease overwinters on diseased leaves and branches with mycelium, produces conidia in the spring of the following year, spreads with wind and rain, infects spring shoot leaves, and diseased leaves begin to appear around the flowering period, and spring shoots are the peak of damage in early and mid-July. A large number of spores are produced on the diseased leaves, and the rate of diseased leaves in the seriously ill garden is more than 50%, and the average number of diseased spots in each leaf is more than 5.

At the same time, the spores of the pathogen can be re-infected repeatedly, and the peak of autumn shoots in early and mid-September is the peak of damage. The onset of the disease basically stopped in mid to late October. Climatic conditions are closely related to the prevalence of diseases.

Generally, after the apple leaves in spring, the rain is early and abundant, and the air humidity is above 70%, and the onset is early and severe. The orchard is densely planted, the canopy is closed, the air humidity is high, there are many weeds, and poor ventilation is conducive to the disease. In addition, the epidemic of the disease is closely related to the age of the leaves, and the pathogen mainly infects the young leaves, and the old leaves that are more than 30 days old are generally no longer infected.

Different apple varieties have different disease resistance, and generally Red Star, New Red Star, Red Crown, Mutsu, Fuji, Red Fuji, Indian, Marshal, and Green Banana varieties are susceptible to disease, Golden Crown, Guoguang are moderately susceptible, and Hongyu, Zhuguang, and Asahi are more disease resistant.

The occurrence and prevalence of this type of disease are related to rainwater, tree status, cultivation management and varieties. Therefore, field management should be strengthened, so that the fruit trees can maintain a strong tree momentum, and the appropriate fruit load, if the fruit tree is weak and the load is too large, it is easy to cause early defoliation; prevention and control of canopy closure (pay attention to summer pruning); Strengthen fertilizer and water management, etc.

If it is one of these two, it can be controlled with fungicides such as Bordeaux liquid, mancozeb, chlorothalonil, etc.