Are the diseases of fruit trees related to the weather?

The occurrence of fruit tree diseases is directly related to the weather. If it is cloudy for a long time, the fruit trees are easy to get sick and the fruit is not sweet. Other pests and diseases are seasonal, although not directly related to the weather, but bad weather is also an inducing factor.

1. What are the economical and simple methods to control fruit tree diseases and insect pests?

Using chemicals to control fruit tree diseases and insect pests is costly and prone to drug resistance. Use the following simple and economical methods to control some pests and diseases: Hunan Talent Network, Changsha Talent Network, Hunan Recruitment Network, Changsha Recruitment Network, Zhuzhou Talent Network, Zhuzhou Talent Network, Xiangtan Talent Network, Hunan Xiangtan Talent Network, Xiangtan Talent Network, Yueyang Talent Network, Yueyang Recruitment Information Network Partners: Zhuzhou Talent Network, Zhuzhou Recruitment Network Partners: Yiyang Talent Network, Yiyang Recruitment Network, Yiyang Talent Network, Yueyang Recruitment Network, Hengyang talent network, Hengyang recruitment network, Hengyang recruitment partners: Changde talent network, Changde recruitment network, Changde talent network, Shaoyang talent network, Shaoyang recruitment network, Shaoyang recruitment partners: Changsha second-hand network, Hunan second-hand network, second-hand network.

1, control of liriomyza sativae in plant ash. Plant ash sows seeds every 5-7 days for 5-6 times continuously, and starts sowing when the new buds grow to about 3 cm, until the new buds mature, and supplements them in time after the intermittent rain. When the dew is still wet in the morning, or after the rain, or after spraying water, plant ash should be sprinkled on the back of the new shoot leaves of Mahuiju in time, and the leaves should always be attached with gray powder during the whole shooting period until the branches and leaves are mature. This method is suitable for the control of liriomyza sativae in nurseries, young orange orchards and potted ornamental oranges.

Lime water is used to prevent canker. Mix 1 part of slaked lime powder and 4 parts of clear water, filter, and dilute the filtrate by 5% to control citrus canker. Spraying once every 10- 15 days, and spraying once every 20 days before each new shoot when the new shoot grows to 5 cm and the young fruit grows to 3 cm in diameter. Spraying the fruit once when clearing the garden after picking can effectively prevent the occurrence of waterlogged orange canker and reduce the damage rate of leaves, fruits and branches. At the same time, spraying 5% limewater at the young fruit stage of Lichun orange can prevent sunburn and improve fruit quality.

3. Clear water controls starscream. Use clear water to control red spider. The method is to use water pumped by machinery such as water pump or sprayer to reach the orchard with hose. Use wire cutters or other fixtures to make the nozzle into a fan-shaped hole, so that clean water can flush the crown evenly with a certain impact force. It can obviously reduce the population density of red and yellow spiders, and at the same time wash away aphids such as scale insects and arrowhead scales, thus reducing the occurrence of soot disease; Washing away the dust on leaves and fruits is beneficial to leaf photosynthesis; It can resist drought in drought and cool and humidify in hot summer to prevent the fruit from being sunburned. But when it is cool in summer, spraying water must be carried out before 10 in the morning. Note that this method is not suitable for the whole flowering period, new shoots and fruit-setting period, but suitable for the mature new shoots and fruit growth and expansion period, so it is necessary to choose clean and pollution-free water sources.

4. gasoline kills longicorn beetles. Firstly, clean the insect dung in the moth hole of the longicorn beetle with iron wire, then directly inject 70# or 90# gasoline into the insect hole with a medical syringe, and seal the insect hole tightly with yellow mud to prevent the gasoline from volatilizing, thus killing the longicorn beetle. The amount of gasoline injected into the first instar larvae, the aged larvae and the aged larvae was 2ml, 4ml and 6ml, respectively. Because longicorn beetles eat many holes, they should inject gasoline into the hole closest to longicorn beetles. If insect dung is still found after injecting gasoline, it should be injected again. This method has a good control effect on longicorn beetles.

5, smoke bone human urine soaking solution to prevent and control arrows and aphids. Soak 0.5 kg of chopped tobacco bones (i.e., residues such as tobacco stems, petioles and veins that cannot be smoked) in 2.5 kg of human urine for 8 days, then filter and spray 25 kg of water to prevent arrowheads or aphids. If 0. 1% washing powder or 0.4% urea is used, the control effect is better.

Second, how to use rainwater harvesting and moisture conservation technology in orchards

In the growing season of fruit trees, timely and appropriate water is needed, which is beneficial to the normal growth and development of branches and fruits and high yield and quality. In the critical period of water demand for litchi, longan flowering, young fruit growth and autumn shoot growth in spring, if drought occurs, it will aggravate soil water evaporation and seriously affect fruit yield and quality and autumn shoot growth. Therefore, water is one of the indispensable conditions for the normal growth and development of fruit trees.

Where does the water man need come from? One is precipitation in the sky, the other is soil water storage, and the third is artificially introduced external water.

Precipitation in the sky. Under natural conditions, the precipitation in the sky is always uneven, or drought or waterlogging is always more than good weather, which often leads to insufficient or excessive water supply.

Soil water storage. Soil water storage mainly depends on the precipitation in the sky. The greater the precipitation, the more water will enter the soil. Heavy precipitation or intermittent precipitation is easy to cause ground loss, and less water penetrates into the soil; Low-intensity continuous precipitation is beneficial to soil absorption and storage of water. Soils with different textures and structures have different water permeability and water storage performance. Sandy soil is coarse and loose, with strong water permeability, but poor water storage; Clay is dense and has strong water storage, but poor water permeability; Loam with moderate sandy quality and viscosity not only seeps water, but also stores water. Where the slope is large and the vegetation cover is thin, the soil absorbs less precipitation; Where the vegetation is flat and dense, the soil absorbs more precipitation. In addition, with the absorption of fruit trees and atmospheric evaporation, soil moisture gradually decreases. The evaporation of soil moisture is related to the air humidity near the ground. The smaller the air humidity, the faster and more the soil moisture evaporates. In the days of continuous sunny, hot and high temperature, the air near the surface layer is relatively dry, but the solar radiation intensity is high, the air temperature and soil temperature increase significantly, the soil water evaporation is large, and the soil water loss is serious, so the drought will develop rapidly. Artificial introduction of external water for irrigation is of course good, but it increases investment and production costs.

Orchard rainwater harvesting and moisture conservation technology is a technology that combines the three to optimize water supply, that is, collecting rainwater from the sky by manual means, increasing soil water storage, keeping soil moist for a long time and ensuring balanced water supply. The main methods are:

1, contour planting

Change slope planting to contour planting. Contour planting is to open terraces along contour lines. The hillside orchard has become a horizontal terrace, with an inward inclination of 1-2 degrees. When it rains, the rainwater of terraced fields can penetrate in situ, which can reduce soil erosion and the soil water content is higher than that of sloping fields. During the drought, the soil water storage capacity is also higher than that of sloping land. According to the experiment, on sloping farmland with a slope of about 2, contour planting reduces runoff by 50-70% compared with slope planting. In 0-70 cm soil layer, soil moisture is high 10-20%, and water retention capacity is 2.5 times higher. Therefore, conditional orchards should be built in the middle of the distance between the upper and lower tree trunks along the contour line, and gradually transformed into terraces with loose and fertile soil, which is beneficial to root growth, soil conservation, water conservation and fertilizer conservation. The outside of the terrace should be slightly inclined to the inside, and the outside is about 15CM higher than the inside.

2. Rainwater collection and storage

A water retaining foundation similar to paddy field foundation is built outside the terrace, which is more than 10 cm higher than the terrace. Dig a water storage ditch inside each terrace. The ditch is about 30 cm deep and 30 cm wide, and there is a mound 10 cm lower than the terrace surface every 5-8 meters. Dig the reservoir regularly inside the steps. The reservoir should be excavated in a place conducive to rainwater collection and irrigation, and the size should be determined according to the needs and possibilities. When it rains, water storage ditches and reservoirs are used to store rainwater, so that the accumulated rainwater slowly seeps into the ground to prolong the wetting time of the orchard.

3. Deep ploughing and water storage

Deep ploughing and water storage is to loosen the soil, thicken the active soil layer and increase the porosity of the soil, thus improving the ability of the soil to receive rainwater. At the same time, the passage of soil moisture moving to the surface is cut off by ploughing and loosening the soil, so as to reduce the chance and quantity of soil moisture escaping from the surface and achieve the effect of water storage.

4. Covering for water conservation

Covering the tree tray with crop straw and plastic film can cut off the capillary connection between evaporation surface and lower soil, weaken the turbulent exchange intensity between soil air and atmosphere, and thus effectively inhibit soil evaporation. Mulching can protect the surface soil from the direct impact of raindrops, stabilize the aggregate structure, accelerate the infiltration speed and depth of precipitation, improve the retention rate of precipitation, and have obvious effects on inhibiting soil evaporation and maintaining soil moisture.

5. Soil improvement and soil and water conservation

The soil environmental conditions of orchards in hilly areas are poor. It is necessary to improve soil aggregate structure by fertilization. The method is to dig an annular ditch or strip ditch around the crown drip irrigation line, and fill it with weeds, soil miscellaneous fertilizer, pond mud, manure and lime in layers to replace the original soil, improve the physical and chemical properties of the soil, create a deep, loose and fertile soil environment, and be conducive to water conservation.

6, grass and water conservation

Planting grass to keep water is to get rid of the vicious weeds in the orchard, and keep the benign weeds and crops planted. Deep-rooted weeds in orchards, shrubs that compete with fruit trees for water, fertilizer and glory, and weeds in tree trays should be removed. Weeds outside the tree tray should be preserved because they do not compete with fruit trees for fertilizer, water and glory. In spring, summer and autumn, some beneficial crops and weeds, such as Leguminosae Stylosanthes, mung beans, soybeans, peanuts, geranium, Chinese milk vetch, etc., can be interplanted among fruit trees by using the open space outside the tree tray, which can not only fix a lot of nitrogen in the soil and absorb free nitrogen in the air, but also significantly enrich the soil, help to store water and consolidate the soil, prevent soil erosion, improve soil fertility and improve orchard micro-fertilizer.

Third, how to control powdery mildew of fruit trees

Symptoms of powdery mildew: white mildew spots appear on both sides of tender leaves, which are mostly round and loose in appearance, and the mildew spots often spread outward from the center. The leaf tissue under the mold layer was initially waterlogged, and then gradually turned green, forming a macula. In severe cases, the lesion spread to the whole leaf, causing the young leaves to wither and the old leaves to distort.

Pathogenesis: Warm and humid is beneficial to the occurrence and prevalence of this disease. The suitable temperature of onset is 18-23℃, which often causes a large number of epidemics after the rainy season. Plants with wet orchards and dark crowns are often seriously ill, and the lower and inner branches are the most prone to disease. Fruit trees such as citrus, papaya, peach and plum are easily affected.

Prevention and control methods: strengthen cultivation management, increase the application of phosphorus, potassium fertilizer and organic fertilizer, enhance tree vigor and improve disease resistance; Combined with pruning, cut off diseased branches and over-dense branches to make them ventilated and transparent; Close planting gardens should be pruned in time to reduce the humidity of the orchard. Spray protection. During the onset of the disease, Bomei 0.3-0.5 degree sulfur mixture or 50% thiophanate-methyl wettable powder 1000 times, every 10 day 1 time, for three times.

Fourth, how to control fruit tree anthracnose

Anthracnose is caused by anthrax longisporum infection. Litchi, longan, citrus, banana, mango, pineapple, loquat, guava, papaya, wampee, carambola, pineapple, Taiwan Province jujube, peach, plum, persimmon and so on. Almost all fruit trees and vegetables in the south are affected. Pathogens mainly survive and overwinter on diseased tissues of diseased branches and leaves for a long time, and can also overwinter on diseased branches and leaves left on the ground. In the early spring of the following year, with the warming of the air and the cooperation of rain, overwintering bacteria produced spores, which were spread by wind, rain and insects and became the first source of infection in that year. When the temperature is 13-38℃ and there is a certain amount of rain, the bacteria can get sick. Every April-165438+1October, the temperature rises (22-29℃), with continuous rainy and hot weather, which is the most favorable climatic condition for the disease to flourish and spread. Anthracnose can harm all parts of the ground, but mainly leaves, branches and fruits, and branches, stems, flowers and seedlings are also harmful. The most susceptible parts of anthracnose are buds, leaves, ears and young fruits. Because the pathogen has the characteristics of latent infection, it first invades the fruit in the young fruit period, and then lurks in the fruit maturity or storage and transportation period. Only under the conditions of high temperature and high humidity will the damage be aggravated and obvious symptoms appear.

Leaf anthracnose can be divided into acute type and chronic type. Acute type mostly occurs in the high temperature season after continuous rainy weather, and the diseased leaves fall off quickly, which often causes serious defoliation of the whole plant. Most of them start from the tips and edges of young leaves, and at first they are light blue with dark brown, like small spots scalded by hot water. The boundary between the diseased part and the healthy part is not obvious, and the small spots quickly expand into large spots with water stains, and the boundary is not obvious, like moire. The diseased leaves rot and fall off quickly. Chronic type mostly occurs in short-term humid weather that clears up quickly, and yellow-brown spots appear from the tip or edge of leaves to grayish white, and the spots expand into irregular shapes, with dark brown edges and slight bumps, and the spots are often in the shape of wheel stripes.

There are two symptoms on the branches. One is that the tender shoots wither from top to bottom in the form of boiling water soup, which is more common in high temperature and high humidity; The other is oval to prismatic brown lesions, slightly concave, which mostly occur near the axillary branches. After the diseased spots spread around the stem, the diseased branches died, showing grayish brown to grayish white with black spots the size of needles on them.

Fruit diseases have three symptoms. One is "dry scar type". Under dry conditions, the peel occurs, the lesion is nearly round or irregular, the boundary is clear, the middle part is slightly sunken, yellow-brown, and it looks like a dry scar. The second type is "tear mark type", which mostly occurs in high humidity weather, and the fruit surface is short or blocky reddish-brown spots with tear marks. The third type is "rotten type", which mostly occurs during the storage and transportation of fruits after harvest. The lesion is amorphous, with obvious edges, brown and slightly concave, which can cause the peel and pulp to rot.

Control methods: (1) Strengthen cultivation management, increase the application of organic fertilizer, timely irrigation and drainage, prevent freezing and insects, enhance tree vigor and improve plant disease resistance. (2) Do a good job in site health and reduce the source of disease. Cut off diseased branches, leaves and fruits, burn them centrally, and clear the garden in winter. (3) Spraying drugs in time to control diseases. Spraying chemicals at each new shoot stage, young fruit stage and fruit expansion stage to protect new shoots and fruits. The available chemicals are: 0.5:0.5: 100 bordeaux solution, or 75% chlorothalonil 800 times solution, or 50% bactericide 600 times solution, 77% Keith Downing wettable powder 1000 times solution, or 70% thiophanate-methyl 800- 1000 times solution.

5. How to prevent fruit tree canker?

Canker is one of the important diseases of fruit trees, which harms citrus, litchi, longan and other fruit trees. The disease harms leaves, branches and fruits, often causing deciduous leaves, dead branches and even seedling death. The fruit of the adult orange tree is damaged, which seriously causes fruit drop and slight disease scar, which affects the quality and causes economic losses. Citrus canker occurred from late March to 165438+ 10, especially in hot and rainy weather and pests such as leaf miner, which mainly harmed new shoots, branches and fruits.

Symptoms of citrus canker: at first, yellow oil spots appeared on the back of leaves, and then gradually expanded into a nearly round shape. The lesion penetrates both sides of the leaf and protrudes slightly, and the tissue is cork-like, and the central depression ruptures in a taupe crater shape. There is a yellow halo around the lesion, with a diameter of 3-5 mm. Sometimes several lesions are connected together to form irregular lesions, and the diseased leaves fall off early. The diseased spots on the branches are similar to those on the diseased leaves, which are nearly round, oval or combined into irregular shapes, pale yellow or yellowish brown, protruding, but there is no yellow halo around them. The lesion can reach the phloem, and when the lesion surrounds all branches and leaves, the branches will die. Fruits and diseased spots are similar to those on leaves and branches, and the surface cork protrusion and central crack are more obvious, which will cause fruit drop in severe cases.

The pathogen of ulcer disease is a kind of bacteria, which can survive in the host tissue for several months, and the pathogen lurks in the diseased tissue for the winter. During the second spring rain, germs overflowed from the diseased area and spread through wind, rain, insects and branches and leaves. Bacteria fall on buds, leaves and young fruits and invade through pores, lenticels or wounds. In the case of high temperature and rainy weather, germs can be repeatedly infected and expand the harm. When the shoot length is 3- 12 cm, it is the peak of pathogen invasion, and the wound caused by liriomyza sativae is an important way to infect the disease.

Prevention and control methods: cultivate disease-free seedlings; When clearing the garden in winter, completely cut off the diseased branches and leaves; It is found that diseased leaves, branches and fruits should be removed and burned centrally; Strengthen cultivation management, strengthen tree vigor and improve tree disease resistance; In spring, summer and autumn, when the leaves do not grow new shoots, the control of liriomyza sativae should be strengthened. Chemical control and spraying should focus on prevention, focusing on protecting young tissues at the new shoot stage and the young fruit expansion stage, especially before and after the typhoon. Under normal circumstances, spray it for the first time when the new buds grow to 2-4 cm, and spray it for the second time when the new buds turn green. The available chemicals are: 10% dichlorvos 300-400 times (for fruitless orchards), or 20% yekunning 500 times, or 50% zineb 800 times, or 500-800 times, or 0.5: 1. The above chemicals are sprayed once every 10- 15 days for 2-3 times in total to achieve the control effect.

Six, how to prevent and control fruit tree diseases?

Phytophthora infestans litchi, longan and wampee. The zoospores of pathogenic bacteria are spread by wind and rain or insects, and are easily infected when it rains continuously, the rain is uncertain for a long time or it is sultry and thunderstorm, and the air humidity is high. Fruits, leaves, spikes and fruit branchlets may be sick, but mature and nearly mature fruits are most affected, and any part of fruits may be sick. At the beginning of the disease, brown irregular spots appeared on the surface of the affected area, and the edge was not obvious. When the temperature and humidity are suitable, the disease spots develop rapidly, which makes the whole fruit black and brown, produces a large number of fallen or rotten fruits, and emits sour wine and yellow-brown juice. There are brown spots on the surface of diseased leaves, and white downy mildew is produced on the surface of diseased parts in the later stage of disease when the humidity is high.

Pathogenic bacteria come from twigs, diseased fruits on residual trees, diseased leaves and diseased fruits that fall to the ground. They overwinter, and the humidity is suitable in spring and summer of the following year, resulting in sporangia, which is spread by wind and rain, insects, leaves and fruits. The occurrence of potato late blight is closely related to residual bacteria and air humidity, and high air humidity is most likely to induce the occurrence and epidemic of potato late blight. During the flowering period of litchi and longan, if it rains continuously and the rain is unclear for a long time, the disease will expand rapidly when the ear is damaged, so that the whole ear will be infected with disease and die. Fruit farmers often call it "retting flowers". Fruit ripens for a long time, which is easy to induce a large number of fruit diseases. When the fruit is damaged, the diseased spots in the fruit quickly spread to the whole fruit, causing the whole fruit to discolor and fall off, resulting in a large number of fruit drops. Therefore, trees with lush leaves and many fruits generally have many diseases; The incidence of moist and fertile soil, lush plants and dark green leaves is more, while the incidence of solid soil, water shortage and poor growth is less; Orchards with low terrain, poor drainage and poor ventilation and light transmission are more likely to induce the disease.

Prevention and control methods: reasonable pruning, so that the crown is ventilated and transparent, reducing the humidity of the orchard. Clean up the orchard, burn the picked fallen leaves and fruits on the ground, and then spray 600-800 times of 70% copper oxychloride wettable powder to reduce the primary infection source. Remove the diseased fruit from the orchard in time, and sprinkle lime and copper sulfate powder under the tree to reduce the source of infection. Drug control. Spray it three times in budding stage, young fruit stage and before fruit coloring, and spray it again 1 time in the orchard with serious diseases before budding stage and half a month before fruit ripening. The medicament can be 600-800 times of 58% erysipelas, 800 times of Kelv, 500 times of 90% ethyl phosphate, 250-300 times of 40% ethyl phosphate wettable powder, 600 times of 50% erysipelas, 600 times of 64% antiviral alum or 600 times of metalaxyl. Or 600-800 times of 36% iprodione, or 400-800 times of 58% carbendazim manganese zinc, or 700-800 times of Dashuangning (75% wettable powder), or 500-600 times of Baikening (40% suspending agent), or more than 70g. Or 600-700 times of antivirus cream (64% wettable powder), 1000 times of cream dew (72% wettable powder), or 2500-3000 times of 50% encore.

Seven, how to prevent freezing injury of fruit trees

1999 Frost weather occurred in some areas of Guangdong during the winter, which caused serious harm to fruits and vegetables. Fruits killed by freezing injury include litchi, longan, mango, pineapple, poncho, banana and papaya. From the point of view of fruit farms with severe freezing damage, fruit trees have the following characteristics: young trees are more seriously damaged than adult trees, lowlands are more seriously damaged than uplands, and leaves with insufficient maturity are more seriously damaged than fully mature leaves. Fruit trees suffer from freezing injury, which leads to frostbite of flower buds, dry branches and serious leaf shedding, which seriously reduces the yield and quality of fruit trees. In severe cases, the branches are dry, the cortex is frozen and cracked, and even the whole plant freezes to death. Here are several effective anti-freezing measures for fruit farmers' reference.

1, apply sufficient winter fertilizer. Fertilizer in winter is mainly organic fertilizer. Organic fertilizer not only helps to raise soil temperature and protect roots from freezing injury, but also helps to replenish nutrients to trees in early spring and reduce freezing injury. Results Heavy fertilizer was mainly applied to the trees before and after fruit picking, in order to supplement the nutrients consumed by the fruits, restore the vitality of the trees, promote the differentiation of flower buds and enhance the wintering ability. At the same time, strengthen spraying foliar fertilizer outside the roots to improve the cold resistance of plants.

2. Ground coverage. Before the frost comes, cover the soil around the roots of plants with straw, straw, weeds and leaves; Or combine with fertilization to cultivate the soil once, and cultivate it under the crown with turf or soil mixed fertilizer; It can be covered with plastic film, and the edge of the film is compacted with soil to prevent heat loss and wind blowing, which can reduce ground radiation cooling, maintain and improve ground temperature and maintain root activity.

3. Irrigation to prevent freezing. Before the arrival of the cold current, the citrus reticulata should be irrigated to store the temperature with water, so as to reduce the temperature difference and keep the ground temperature relatively stable during the cold freezing period, thus reducing the freezing damage. It is best to irrigate at noon and infiltrate at night.

4, trunk dressing. When the temperature is low, wrap the main branch tightly with straw.

5. The trunk is painted white. When cleaning the orchard in winter, the main branches of the fruit trees are painted white.

6. Cut off the buds. In late autumn, bamboo shoots are immature, with thin and pale leaves, low organic matter accumulation, low nutrient concentration of cell fluid, easy to be frozen, and deciduous leaves, which should be cut off.

7. Smoke to prevent freezing. It's best to mix sawdust and weeds with soil as fuel, ignite when the cold wave comes, and let the smoke cover the whole park.