What happens when big dark spots appear on the leaves of a pear tree after a rain?

The pear tree suffers from pear scab caused by scab.

Control of black disease in pear trees.

Pear scab disease is mainly harmful to the young tissues of pear trees (young leaves, young fruits, tender leaves, etc.), the diseased part produces black mold, the leaves are damaged, the lesions mostly occur on the back of the leaves, which are irregularly shaped, the leaf veins and petioles are elongated and oval, and the black mold layer soon appears on the lesions.

The prevention and control of pear scab should be carried out in an orderly manner, first of all, after the pear tree falls into flowering, combined with sparse flowers and fruits to cut off the diseased shoots, which has a great effect on controlling the onset of the disease throughout the year, followed by the prevention and control of drugs, 7-10 days after the operation of 20 dymori ammonium 1000 times, 40 Fuxing 8000-10000 times, and 167 grams of Xiansheng for prevention and control; At the peak of the disease, in mid to late June, it can be treated with 8000-10000 times of 40 Fuxing, 167 grams of Xiansheng, and 800 times of 80 times of Dysen zinc. After the pear tree falls into flowering, it is combined with thinning flowers and fruits to cut off the diseased shoots, which has a great effect on controlling the onset of the disease throughout the year.

Fertilization characteristics of pear trees at different times.

1. Foliar spraying of boron fertilizer during flowering.

Pear blossoms have a large demand for boron, and sufficient boron is needed during the flowering period, so it is recommended that fruit growers spray boron fertilizer once on the foliar surface at the first flowering stage and after flowering. Ribery Yanwo chelate boron fertilizer can be used, which can promote pollination and improve fruit set.

Second, the young fruit stage topdressing nitrogen, phosphorus and potassium fertilizer.

It is generally recommended that fruit farmers should combine cultivating and weeding after the pear tree flowers and when the young fruits begin to grow, and each tree can be ditched and applied about the key nitrogen fertilizer, potassium fertilizer kilograms, and phosphate fertilizer kilograms. The main purpose of this fertilization is to promote the growth of roots and shoots and promote fruit expansion.

3. Apply puffing fertilizer during the fruit expansion period.

In late June to mid-July, it is necessary to apply puff fertilizer. It is recommended to apply 30-50 kg of human feces and urine per plant, mix kg of urea, open a ditch and water it, and then cover the soil in time. At the same time, spraying potassium dihydrogen phosphate every 15-20 days, spraying 3-4 times in a row, can reduce the occurrence of pests and diseases, and at the same time promote fruit growth and good growth.

It should be scab disease of the pear tree.

Scab disease is a fungal disease that can damage the leaves, fruits, shoots and other parts of the pear tree. The pathogenic bacteria overwinter with conidia or mycelium in the diseased parts of the pear tree or the diseased branches and rotten fruits on the ground, and the temperature is suitable in the spring of the next year, and the disease begins to harm the tender shoots and shoots of the pear tree in the later stage, and the later stage with the rain and insect migration spreads, especially in the late growth period, it encounters continuous rainy weather, which will cause a large outbreak of scab disease in the orchard! In years with less rain, scab is less likely to occur!

1. Black spots in pear tree flowering are fungal diseases, which mainly harm pear leaves, fruits and new shoots.

2. The tender leaves of Muhe were the earliest. At first, black spots of pinhead size appeared, and then gradually expanded into round or irregular lesions, which were grayish-white in the middle and black-brown on the edges. In the high temperature and high humidity environment, black mold is produced on the surface of the lesion, which is the conidia and spores of the disease.

The lesions on the surface of the Ye Xun stool can be connected into irregular large lesions, which can cause early defoliation when the damage is serious.

Summary. May be pear black spot. Pear black spot disease is a fungus of the genus Cross-Chain, which is a common disease on Japanese and Korean pears and snowflake pears.

for damage to leaves and fruits. The disease began in mid to late May in the northern fruit area, and the peak period was July and August. Generally, the onset is more severe in autumn, and the onset is early and severe in years with high temperature, high humidity, and more rainfall.

May be pear black spot. Pear black spot disease is a fungus of the genus Cross-Chain, which is a common brother disease on Japanese and Korean pears and snow pears. for damage to leaves and fruits.

The disease began in mid to late May in the northern fruit area, and the peak period was July and August. Generally, the onset is more severe in autumn, and the onset is early and severe in years with high temperature, high humidity, and more rainfall and early noisy dust bridge.

The spring shoot leaf disease is the focus of slippery and prevention and control. 1. Agricultural prevention and control: timely cultivation and hoeing, thinning overly dense branches and vertical strips, and improving ventilation and light transmission.

Clean the orchard after the leaves have fallen and sweep away the fallen leaves. 2. Pesticide prevention and control: focus on protecting spring shoot leaves, autumn shoot leaves only need to be controlled in the early stage of growth, and it is not advisable to use too much medicine.

The pesticides that can be selected are: 3% polyantimycin aqueous solution 300 500 times, 10 polyoxymycin 1000 polyantimycin 1500 times liquid, 4% pesticide 120 fruit tree special type 600 800 times liquid, 5 promethanin wettable powder 1000 times liquid.

3. Spraying period: these pesticides should be mainly polyantimycin, and other drugs should be used alternately. The first time it was sprayed immediately after the flowering fell, the second time it was measured in mid-May, and the third time it was delayed at the end of June or early July at the beginning of autumn shoots.

4. Spray protectant: spray 1:3 on sunny days in June

Bordeaux liquid 240 twice with an interval of 15-20 days. In July, the protective agent was sprayed 1:3 on sunny days

Type 240 Bordeaux liquid 1 2 times, 15 to 20 days apart. In the rainy season, fungicides can be sprayed on the trees 1 2 times, mainly with 300 500 times of polyantimycin, and other fungicides can be used alternately.

Got it. Good.

Abstract 2: Eliminate the source of the disease.

If it is found that the leaves of the pear tree are infected with this disease, the weeds in the pear orchard should be removed, the diseased leaves, fruits and diseased tips should be cut and burned, and then summer pruning should be carried out to ensure good ventilation and light transmission. In addition, because the pathogen of brown spot disease mainly overwinters on leaves, it is necessary to remove the fallen leaves in the garden in time after picking the fruits and falling leaves, and bury or burn them in a concentrated way to eliminate the pathogen.

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1. Strengthen management After the pear tree is harvested, fertilizer should be increased to promote the growth of the tree and improve disease resistance. In the rainy season, attention should be paid to drainage, reduce the humidity of the orchard, and limit the development and spread of diseases.

2. Remove the source of the disease If it is found that the leaves of the pear tree are infected with this disease, the weeds in the pear orchard should be removed, the diseased leaves, diseased fruits and diseased tips should be cut and burned, and then the summer pruning should be carried out to ensure good ventilation and light transmission. In addition, because the pathogen of brown spot disease mainly overwinters on leaves, it is necessary to remove the fallen leaves in the garden in time after picking the fruits and falling leaves, and bury or burn them in a concentrated way to eliminate the pathogen.

3. Drug prevention and control Generally speaking, before the pear tree germinates, it is necessary to combine the prevention and control of other diseases, such as pear rust, spray Bordeaux liquid once, and spray the second spray after flowering. When the season of high temperature and rain comes, it is sprayed again around May. Generally, spraying 2-3 times can achieve a good control effect.

Follow the method above.

Thanks well, hope it helps.

Pear scab is the main disease of pear trees, the disease is mainly harmful to the young tissues of pear trees (young leaves, young fruits, tender slightly, etc.), the disease part produces black mold, the leaves are damaged, the lesions mostly occur on the back of the leaves, it is a faded green irregular shape, the leaf veins and petioles are elongated and oval, the black mold layer appears soon on the lesions, the leaves turn yellow and red, and it is easy to fall off early. The lesions of young fruits begin to be pale yellow dots, and then expand into round, and the black mold layer is gradually concave, hardened or cracked, and is easy to fall off early. The lesions on the young shoots are oval or nearly round, with black mold, depressions, cracks, and scabs.

The young shoots extracted from the diseased shoots have lesions mostly at the base of the shoots, and the bud scales are loose and do not fall. Growing branches and autumn shoots are susceptible to disease, and in severe cases, they die. The lesions of the inflorescence are mostly at the base of the peduncle, which gradually withers and wilts.

Pear scab disease can occur from the flowering stage to the fruit ripening stage, mainly harming all green and tender tissues in the upper part of the pear tree such as scales, leaves, petioles, leaf marks, new shoots, flowers, fruits, etc., and invade from the flowering stage, resulting in flower and fruit dropping, and the fruit heart becomes black during the fruit harvest and storage period in August after the invasion of the pathogen in March.

Prevention and control methods: lAfter the pear falls flowering, combined with thinning flowers and fruits, pruning the diseased shoots has a great effect on controlling the onset of the disease throughout the year.

2.7-10 days after flowering, 1000 times of 20 dysenammonium, 8000-10000 times of 40 Fuxing, and 167 grams of Xiansheng were used for control. 3.

At the peak of the disease, in mid to late June, 40 Fuxing 8000-10000 times, Xiansheng 167 grams, and 80 Dysen zinc 800 times were used for prevention and treatment.

Hello, glad for your question. The edges of the leaves of the pear tree are blackened, which is most likely due to brown spot. This disease generally occurs at high temperature and high humidity, and after getting sick, it is necessary to do a good job of field drainage and spraying with carbendazim solution**.

It may also be caused by improper fertilization or drug use, and if too much fertilizer is applied or the concentration is too large, such an undesirable situation will also occur.