What are the main diseases of peach trees?

Bacterial diseases. It mainly harms roots and neck, forms tumors, and causes poor growth or death of peach trees. This disease will attack many kinds of fruit trees and crops.

1, the victim symptoms mainly occur in the root neck, but also in the lateral roots or branch roots. The tumor was milky white or reddish at birth, smooth and soft, then gradually brown, lignified, hard and rough. The tumor occurred in the smaller branch roots and the larger root neck, and the tumor at the root neck had the greatest influence. The damaged peach trees grow badly, the plants are short, the fruits are few, the quality is poor, and even the whole plant dies in serious cases.

2. Pathogenic bacteria live in cancer tissues or soil, and can spread with rainwater runoff or irrigation water and diseased seedlings, and invade through wounds. Alkaline soil is beneficial to the disease, and continuous cropping nursery and peach orchard are easy to get sick.

3, prevention and control methods

(1) Miao Di and Taoyuan try to avoid continuous cropping.

(2) Strictly put an end to sick seedlings leaving the nursery; Strengthen quarantine when building a new peach garden to prevent the introduction of sick seedlings.

(3) Strengthen the inspection of orchards, dig out the topsoil of suspected diseased plants, scrape it off with a knife or completely after finding diseases, and disinfect it with 1% sodium chlorate or 0. 1% mercuric chloride solution; You can also soak the roots (for sick seedlings) or irrigate the roots (for big trees) with 20 times of Geneline solution.

(4) Nursery should use disease-free soil to raise seedlings and cultivate robust disease-free seedlings.

(5) Strengthen soil management, apply fertilizer rationally, improve soil and enhance tree potential.

Shrinking leaves

[symptoms]

Peach leaf shrinkage disease mainly harms the tender parts of peach trees, mainly leaves, but also harms flowers, tender shoots and young fruits.

Leaves: In spring, when the tender buds are just pulled out from the bud scales, they appear curly red. With the gradual development of leaves, the degree of curling and shrinking will also increase, and the leaves will become thicker, brittle and reddish brown. In late spring and early summer, a layer of gray-white toner, the ascomycete layer of the pathogen, is produced on the surface of the leaves. Finally, the diseased leaves turn brown, scorch and fall off. After the leaves fall off, axillary buds often germinate and take out new buds, and the new leaves are no longer hurt.

Stem tip: the damaged stem tip is grayish green or yellow, shorter than the normal internodes, slightly enlarged, and the leaves on it are often overgrown. In severe cases, the whole branch withered.

[pathogen]

The pathogen is Taphrina deformans (Berk) Tul, belonging to Ascomycetes subfamily. Ascomycetes and ascospores are formed in the sexual stage of pathogens. Ascomycete spores can also germinate inside or outside the ascomycete to produce spores. Spores are ovoid and can be divided into thin-walled and thick-walled types. The former can germinate directly, and the latter can resist bad environment and can be used for eye rest. Japanese examination records can survive 1 1 year.

The optimum temperature for budding is 20℃, the lowest is 65438 00℃, and the highest is 26~30℃. The optimum infection temperature is 10- 16℃.

[route of infection]

The pathogen overwinters mainly on the scales of peach buds with thick-walled spores and also on the bark of branches. In the next spring, when the peach buds germinate, spores germinate, directly penetrate the epidermis through the bud tube or invade the young leaves through the stomata.

Because germs can remain on the branches for more than 1 year, there was a serious illness last year, and there are still many germs left, and there will be another serious illness next year.

[Control Method]

1. Chemical control: When the petals are red (unexpanded), spraying 2-3 pomeranite sulfur mixture or1:100 bordeaux solution once can kill the overwintering germs on the trees. You can also spray 30 times of 45% crystal sulfur mixture, 500 times of 70% mancozeb wettable powder and 1000 times of 70% thiophanate-methyl wettable powder. Pay attention to careful medication. After the peach trees germinate, they generally don't need to be sprayed again.

2. Strengthen management: remove the diseased leaves in time before they form powdery substances, and focus on incineration, which can reduce the source of overwintering bacteria in that year. Peach trees with serious diseases should be fattened in time due to a large number of dead leaves and fallen leaves, and cultivation management should be strengthened to promote the recovery of tree potential.

Iron deficiency yellow leaf disease of peach trees

[symptoms]

The leaves are green and reticulate. With the development of the disease, the degree of leaf chlorosis is aggravated, the whole leaf turns white, and the leaf edge is scorched, causing deciduous leaves. When iron deficiency is serious, the top of the new shoot will die.

[etiology]

Because iron is difficult to transfer in plants, iron deficiency symptoms usually begin with young leaves at the top of new buds.

Iron can catalyze chlorophyll synthesis, and iron is one of the components of respiratory enzymes. When iron is deficient, chlorophyll synthesis is inhibited, and plants appear yellowing, yellowing and even albinism.

[occurrence conditions]

Generally speaking, judging from the iron content in the soil, the garden soil is not iron-deficient, but in the soil with heavy salt, soluble ferrous iron is converted into insoluble ferric iron, which cannot be absorbed and utilized by plants, making peach trees in an iron-deficient state. It can be said that all factors that aggravate the degree of soil salinization can aggravate iron deficiency. It can be said that all factors that aggravate the degree of soil alkalization can aggravate the performance of iron deficiency symptoms. For example, when the water on the ground evaporates during drought, the salt is concentrated on the soil surface; In depressions with high groundwater level, salt accumulates on the surface with groundwater; The thick soil and poor drainage are not conducive to salt leaching to the lower layer with irrigation water, which is prone to yellow leaf disease.

[Control Method]

Improving soil and releasing fixed iron are fundamental measures to prevent iron deficiency; Appropriate supplementation of soluble iron can treat this diseased tree.

1. Improving soil alkali control: Measures to increase soil organic matter content, such as applying more organic manure and planting green manure, can change the physical and chemical properties of soil and release fixed iron. Measures to improve soil and control alkali, such as digging ditches to drain water and lowering groundwater level; Changing sand infiltration into viscosity and increasing soil permeability are the fundamental measures to control yellow leaf disease.

2. Appropriate iron supplementation: In order to save seriously ill trees, soluble iron can be supplemented in various ways.

Spraying 0.3%-0.5% ferrous sulfate solution or mixed solution of ferrous sulfate: copper sulfate: quicklime: water = 1: 1: 2.5: 360 on branches before germination can control diseases, but it can't last long.

The mixture of ferrous sulfate and organic fertilizer in the ratio of 1: 5, with 2.5~5 kg per plant, can have an effect of more than two years. The application of chelated iron (ferric EDTA) in soil has obvious effect on yellow leaf disease.

Before the peach trees germinate, the injured lateral roots are soaked in 30-50 times ferrous sulfate solution, and each plant is irrigated with 100 kg liquid medicine; You can also put 0.5 kg ferrous sulfate into the jar 250 times, find out the roots 0.5 cm long in each direction and insert them into the bottle, with 6 bottles per tree. Buried in the soil, absorbed by the roots for 24 hours, take out the bottle. This method saves medicine and takes effect quickly.

Before germination, the trunk was injected with ferrous sulfate or ferric citrate 1000-2000 times. Someone injected 200 times ferrous sulfate solution and 200 times zinc sulfate solution. Improper use of injection is prone to drug damage, so we should try it carefully.

Strengthen management and strengthen tree potential. Apply more organic fertilizer, pay attention to drainage in low-lying and waterlogged areas, properly apply lime or calcium superphosphate to acid-base soil, improve soil, pay attention to salt drainage in saline-alkali soil, prune reasonably, reduce branch damage, and avoid continuous cropping in Taoyuan.

Control pests and diseases on branches, control pests and diseases, and control pests on peach trees such as scale insects, aphids and longicorn beetles. As soon as possible. Paint the trunk white in winter and spring to prevent frostbite and sunburn.

[Chemical Protection and Prevention]

Before germination in early spring, scrape off the diseased tissue at the glue-flowing part, apply 30 times of 45% crystalline sulfur solution or Pomei 5% stone sulfur mixture to the wound, and then apply white lead oil or coal tar for protection. Chemical control can be carried out by using 1000 times of 50% thiophanate-methyl ultrafine wettable powder, 800 times of 50% carbendazim wettable powder, 1500 times of 50% iprodione wettable powder or 2000 times of 50% procymidone wettable powder, and the control effect is good.

Scrape the branches with serious gum flow in autumn and winter, and disinfect the wound with Pomei 5-6 degree stone sulfur mixture or 100 times copper sulfate solution; Or brush your teeth with 1︰4 alkaline water, which also has certain curative effect. What is infectious peach gummosis? How many kinds of fungi are there? What are the characteristics of their hyphae? What kind of medium and formula is this fungus suitable for?

Peach gum disease mostly occurs in the main branches, trunk and fork angles of peach trees. At the early stage of the disease, the affected part was slightly swollen and overflowed with transparent glue, and the gummosis became worse after the rain. Then the gum gradually becomes jelly-like, loses water and becomes yellow-brown, and finally becomes a hard amber rubber block. When the fruit is sick, the yellow gum overflows from the core and the surface of the fruit. The diseased part is hard and sometimes broken, so it can't be eaten.

Insect injury, illness injury, frostbite, hail injury, sunburn and other injuries. Can cause non-infectious peach gummosis (no pathogen); In addition, due to heavy soil, poor drainage, excessive or insufficient irrigation and other reasons, the physiological function of trees is impaired, and gummosis is an infectious peach gummosis caused by fungi. Spores of asexual generation spread by wind and rain, invading from wounds and lateral buds, and there are two peaks at 1, namely from late May to early June and from early August to early September.

In order to prevent peach gummosis, it is necessary to spray drugs in time to prevent pests and diseases, and paint the trunk white to avoid freezing injury, sunburn and mechanical trauma. At the same time, it is necessary to strengthen fertilizer and water management, enhance tree vigor and improve tree disease resistance. Spraying Bomei 4 ~ 5 degree sulfur mixture 1 time before bud expansion, and spraying 50% carbendazim 1000 times solution 1 time every half month during the growth period, 4 times.

Peach scab

Symptoms:

1. Fruit: The disease mostly occurs on the shoulders of fruits, with dark brown round spots first and then black nevus spots with a diameter of 2 ~ 3 mm. In severe cases, the lesions are clustered together. Sick fruits often crack. The fruit often falls off early after the fruit stalk is damaged.

2. New bud: After being killed, it presents an oblong, light brown lesion with a size of 3×6 mm, then turns dark brown and further expands, and the affected part bulges, which often causes glue flow. The boundary between diseased tissue and healthy tissue is obvious, and bacteria only harm the surface and do not go deep into the interior. In the next spring, black spots can be produced on the diseased spots.

3. Leaves: Irregular or polygonal gray-green lesions appear on the back of leaves. Later, the affected part turned black or purple, and finally the affected part dried up and fell off to form a perforation. The lesion is very small, rarely exceeding 6 mm. On the midvein, a long dark brown lesion can be formed. When the condition is serious, it can cause deciduous leaves.

Pathogenic conditions:

1. In rainy and humid years or regions, the disease is more serious.

2. Orchards with low humidity or dense planting, lush foliage and relatively closed are also prone to diseases.

3. Generally, late-maturing varieties are more susceptible to diseases. Yellow-fleshed peach and Shanghai peach are more susceptible to diseases, while Tianjin peach and Feicheng peach are more resistant to diseases. Nectarines are more serious

Prevention and control methods:

1. Removal of primary infection source: combined with winter shearing, remove diseased nuclei, hard fruits and residual piles, and burn or bury them deeply. During the growth period, diseased branches, dead branches and diseased fruits can also be cut off.

2. Chemical control: Before flowering, spray Bomei 5 degree stone sulfur mixture, 0.3% sodium pentachlorophenol or 45% crystal stone sulfur mixture 30 times. Half a month after flowering, spray 500 times solution of 70% mancozeb wettable powder or 800 times solution of 80% anthrax thiram wettable powder and 70% thiophanate-methyl wettable powder 1000 times solution. The above chemicals are used alternately with 0.5: 1: 10o zinc sulfate lime solution or 0.3 Baume lime mixture, half for each.

3. Strengthen management: pay attention to drainage after rain and prune reasonably to prevent the branches and leaves from being too dense.

4. Choose disease-resistant (disease-avoiding) varieties: In places with frequent and recurrent diseases, early-maturing varieties can be planted.

5. Fruit bagging: bagging 3-4 weeks after flowering.

Peach perforation

Perforation is a common disease of peach trees. It occurs in all peach areas, especially in coastal and lakeside areas in rainy years, which often causes a large number of leaves to be perforated and fall off early (Figure 1), weakening tree vigor and affecting yield.

Peach perforation can be divided into bacterial perforation, fungal perforation and brown spot perforation. They not only harm peach trees, but also harm plums, plums, apricots and cherries.

symptom

1. Bacterial perforation is the most common disease, which mainly harms leaves, branches and fruits. The damaged leaves first appear oil spots, and then expand into round or irregular lesions, brown to purple-brown, with yellow-green halo around the lesions. When the weather is wet, the affected part overflows with pus, and soon the affected part dries up, falls off and is perforated. The damage of branches can cause ulcers: one is spring ulcers. When the leaves spread in spring, dark brown scabs appeared on the branches, mostly on infected branches pulled out last summer. The diseased spots can spread to the branches vertically and horizontally, and in severe cases, the branches can be dried up. The other is summer ulcer, which mostly occurs on the new shoots pulled out that year. Centered on the lenticels of the host, there are oily brown to purple brown round or oval spots, which are slightly sunken, but the spread of the spots is limited and the infectivity is not great.

2. Brown, round or amorphous lesions appear after the leaves are damaged. When the leaves are wet, a gray-black mold layer grows on the back of the lesions, and finally the lesions fall off and are perforated. The damaged branches have oblong black-brown spots, purple-brown edges, cracks and gluing. The damaged fruit has brown spots on the red edge and a slight depression in the middle.

3. The diseased leaves of brown spot perforation are round or nearly round, brown, with reddish-brown edges and slightly ringed. When wet, there are gray-brown mildew layers on both sides, and finally the affected part is dry and perforated with neat edges. The diseased spots on new shoots and fruits are similar to leaf spot disease, and mildew layer will also grow when wet.

pathogen

The pathogen of bacterial perforation is bacteria, called Xanthomonas. The thallus is short and rod-shaped, with 2~6 flagella at one end (Figure 2), and the optimum temperature for its development is 24~28℃. The pathogen can survive at the branch ulcer for more than 1 year.

The pathogen of mildew spot perforation is Clastroporium carpohilum (Lev) aderh, which belongs to Hemiptera subfamily. Conidia oval to spindle-shaped, with 4-6 conidia walls, light brown.

The pathogen of brown spot perforation is called Pseudocercospora annulata Y.L. Gueat X.J. Liu = Pseudocercospora annulata, belonging to Hemiptera subfamily. Conidia are rod-shaped and brown with 3~ 12 conidia (Figure 3).

Occurrence law

The pathogen of bacterial perforation mainly overwinters in the ulcer spots in spring. Before and after the peach blossom in the following year, fungus pus overflowed and spread through wind, rain and insect bites.

Sowing infection. When the tree is weak, the incubation period is only 4-5 days, and when the tree is strong, it can be as long as 30-40 days. Warm, rainy and foggy dew is conducive to the occurrence of diseases.

The pathogen of mildew spot perforation overwinters in the disease tip or bud scale with hyphae and conidia. Conidia grow in the warm and humid spring of the following year and are affected by wind and rain. Low temperature (average temperature is about 20℃), rainy and humid weather is suitable for this disease.

Brown spot perforation overwinters with mycelium in diseased tissues or lurking in diseased stem tips. In the second spring, when the temperature rises, conidia will grow and spread when it rains, and will be infected by wind and rain.

Prevention and cure method

1. Do a good job of cleaning the garden in winter, thoroughly remove dead branches, leaves and fruits, and spray 1~2 Baume sulfur mixture once before germination in spring, which can greatly reduce the source of overwintering bacteria.

2. Strengthen the management of fertilizer and water, increase the application of organic fertilizer and phosphorus and potassium fertilizer, and maintain moderate fruit yield, so as to keep the tree vigorous and enhance the disease resistance.

3. Spraying 65% zineb wettable powder with 500 times solution for 2~3 times in the early stage of the disease can prevent and treat various perforation diseases at the same time, or spraying 45% Tekdo emulsion for 2000 times has a good effect.

peach bacterial shot hole

Bacterial diseases. It mainly harms the leaves and fruits of peach trees, causing the leaves to fall off and the fruits to crack.

1, the lesion on the lesion symptom leaves is nearly round, about 2-5 mm in diameter, reddish brown, or several lesions are connected to form a large lesion. There is a yellow-green halo at the edge of the lesion. After that, the diseased spots died and fell off, and the leaves were serious. The fruit was damaged, at first it was small round spots with light brown water stains, and later it expanded into brown and slightly concave. Disease spots are easy to crack into stars, deep and wide, and diseased fruits are easy to rot.

2. Pathogenic bacteria mainly overwinter at the tip of the disease, and pus overflows the affected area in the following spring and is spread by wind, rain and insects. Invasion of pores and lenticels. Generally, it occurs in mid-April. After the blades are unfolded, the rainy season in May-June and the typhoon season in August-September are the peak seasons throughout the year. The orchard is closed, the drainage is not smooth, and the trees are weak. Generally, the early-maturing varieties on fruits are more prone to diseases, especially when it rains at maturity.

3, prevention and control methods

(1) When pruning in winter, pay attention to remove diseased dead branches and eliminate germs.

(2) Spraying 65,438+0 ︰ 65,438+0 ︰ 65,438+000 times Boer solution (forbidden after leaf spreading) or spraying Bomei 5-degree sulfur mixture at the germination stage of early spring peach buds; Spraying zinc sulfate lime solution (zinc sulfate 500g, quicklime1000g, water100kg) or 65% zineb wettable powder 500 times at onset.

(3) Strengthen ditching and drainage to reduce field humidity; Reasonable pruning (including summer pruning), improve ventilation and light transmission, and avoid canopy; Increase the application of phosphorus and potassium fertilizer to enhance the tree potential.

Peach anthracnose

This disease is the main disease of peach trees in the south of the Yangtze River, which mainly harms peach fruits and branches. In severe cases, a large number of branches died and fruits rotted.

1, injury symptoms: young fruits quickly dry up into stiff fruits and hang on branches; The diseased spots of larger fruits are brown, which will produce pink mucus (pathogen spores) when wet, and the diseased fruits will fall off quickly, or the whole fruit will rot and lose water and become stiff fruits hanging on the branches. Branch diseases mainly occur on early spring fruiting branches. The lesion is brown, rectangular and slightly concave, accompanied by gummosis. When the weather is wet, the spots are also covered with pink spores. When the lesion surrounds the branch 1 week, the upper part of the branch will die, the dead part of the diseased branch will shrink and droop, and the leaves will roll into a tube and extend forward.

2. The incidence of fungal diseases. Mycelia overwinters on diseased branches and fruits, produces spores in early spring of the following year, infects fruiting branches, and then spreads to flowers and fruits one after another, which aggravates the damage.

It is easy to get sick when it is rainy and sultry, and it often breaks out after continuous rainy or heavy rain; The temperature in the garden is low, the drainage is not smooth, the pruning is rough, the branches are too dense, the trees are weak, and it is easy to get sick when nitrogen fertilizer is applied.

The disease occurs three times a year in Shanghai, and occurs on fruiting branches from mid-March to early April. It occurs on young fruits in the first half of May, and at the fruit maturity in June and July. In the whole year, the young fruit period suffered the most.

The incidence varies greatly among varieties. Generally, early-maturing varieties are the most serious, followed by middle-maturing varieties, and late-maturing varieties have stronger disease resistance.

3, prevention and control methods

(1) When pruning in winter, carefully remove dead branches, dead fruits and stumps from trees to eliminate the source of overwintering diseases. Perennial aging branches and weak branches are easy to accumulate and hide germs, and should also be cut off. At the same time, the main lateral branches that are too high and too large should be retracted, which is beneficial to the renewal and rejuvenation of crown branches and the work of clearing the garden and spraying drugs.

(2) Cut off the diseased branches from germination to flowering in time to prevent reinfection; Fruit branches with symptoms of leaf curling should also be cut off and buried deeply.

(3) Selecting and planting disease-resistant varieties.

(4) Strengthen drainage, increase the application of phosphorus and potassium fertilizer, enhance the tree potential, and avoid leaving branches too dense and too long.

(5) Spraying 1-2 times 1︰ 1︰ 100 times bordeaux mixture at the germination stage (forbidden after leaf spreading). The young fruit stage begins after flowering, and the zinc-copper lime solution (zinc sulfate 350g, copper sulfate 150g, quicklime 100kg, water 100kg) is used once every 7- 100 days for 3-4 times.

Peach blight

Also known as decay. It mainly harms the branches of peach trees, causing the branches to die, and in severe cases, the whole plant dies.

1. At the initial stage of symptoms, the affected cortex is slightly swollen, slightly purplish red, with colloid. Finally, the cortex turned brown and died, with the smell of distiller's grains and small black pimples on the surface. When the tree is strong, the diseased spots sometimes heal themselves. When the tree is weak, the disease spots quickly spread to both ends and sides, eventually leading to the death of branches. In the early stage of diseased branches, new shoots grow poorly, leaves turn yellow, old leaves curl and wither, and then die with the development of diseased parts.

2. The incidence of fungal diseases. The pathogen overwinters in the ward with mycelium, ascomycetes and conidia. The next spring, hyphae continued to spread in the affected area, while sporadic spores were spread by wind and rain, insects and so on. , and was invaded by wounds or lenticels, and the most serious disease occurred in May and June. Weak trees, low humidity in the garden, sticky soil, excessive pruning due to freezing damage to the branch cortex in winter, too many branches wounds, poor healing, and burns to the cortex can all cause diseases.

3, prevention and control methods

(1) Strengthen the management of fertilizer and water in orchards, prune and keep fruits reasonably, and prevent the decline of trees.

(2) After scraping the lesion with a sharp knife, brush the wound with 20% antibacterial agent 402 100 times solution or copper sulfate 100 times solution.

(3) When spraying carbendazim, zineb and zinc-copper lime solution to control other diseases during the growth period of peach trees, attention should be paid to spraying chemicals to protect branches.