Powdery mildew of common diseases of strawberry

Schematic diagram of strawberry powdery mildew

It is well known that strawberry is a kind of ornamental and edible fruit and vegetable plant. due to the development of cultivation technology in recent years, strawberry planted on the ground can grow independently in flowerpots. Conservation management can still blossom and bear fruit, but there is always a case where strawberries are susceptible to powdery mildew in the absence of farming experience, so what to do when strawberries become infected with powdery mildew?

First, the cause of strawberry powdery mildew

The incidence of strawberry powdery mildew is related to temperature and humidity, which is generally caused by low temperature and high humidity, and the onset temperature is about 12 ℃-23 ℃. Powdery mildew is easy to be infected in autumn or spring with continuous overcast, rain and fog, with less sunshine, low temperature and high humidity, and it is also easy to be infected by pathogens. Strawberry cultivars with high resistance to powdery mildew should be selected, and strawberry varieties with high resistance to powdery mildew should be selected: Tudra, Hong Shimei, Xingxiang, Fengxiang and Dasai.

Symptoms of strawberry powdery mildew

Powdery mildew mainly harms strawberry leaves, petioles or fruits. Thin white hyphae grow on the back of strawberry leaves in the early stage, but in the later stage, the hyphae are dense into powder, and poor control will gradually aggravate the death of the whole leaf; flowers and buds will cause varying degrees of harm, poor pollination, young fruits can not grow normally, there is a layer of white powdery matter on the fruit surface, the fruit grows slowly, hardened, can not be eaten, the disease spreads quickly, and the disease should be controlled in time. The prevention and control of strawberry powdery mildew in greenhouse must adhere to the strategy of "prevention first, whole process control", and good results can only be achieved through the implementation of agriculture, pesticides and other comprehensive supporting measures.

3. Control methods of strawberry powdery mildew

1. Select disease-resistant varieties

Disease-resistant varieties such as Mingbao and Yixiang can be selected, and susceptible varieties such as Fengxiang should not be selected as far as possible.

two。 Implement crop rotation and change stubble

Rotation of flood and drought can be carried out in seriously diseased fields. Cruciferous vegetables and legumes are suitable for rotation crops, while Solanaceae crops and strawberries have common diseases and should not be used as rotation crops.

3. Clean the countryside

After harvesting, strawberries should clean up and burn the diseased remains in time; remove all kinds of weeds in the field before planting; remove diseased leaves, diseased fruits and old leaves in time during the growth period, and take them out of the shed for centralized burning or deep burial, so as to avoid re-infection of bacteria with Rain Water and airflow. Reduce the number of bacteria sources.

4. Strengthen cultivation management

The strawberry field should be deeply ploughed and turned over before transplanting, and the greenhouse, soil and transplanting seedlings should be disinfected to reduce the primary source of bacteria; weeds should be removed before plastic film mulching to reduce the role of weeds as intermediate hosts of powdery mildew; cultivate strong seedlings and transplant at the right time; ensure suitable plant and row spacing; do a good job in greenhouse ventilation, pay attention to timely drainage after rain, and reduce field humidity. Reasonable fertilization, base fertilizer is mainly rotten organic fertilizer, phosphorus and potassium fertilizer, topdressing is mainly nitrogen, phosphorus and potassium compound fertilizer, avoid heavy application of nitrogen fertilizer, improve plant disease resistance; scientific use of water, pay attention to drainage after rain, reduce field humidity and reduce pathogen infection. After budding, fruit expansion period and harvest peak period, special attention should be paid to water management, it is best to use drip irrigation under plastic film, do not flood irrigation, reform the cultivation system, and implement the system of planting once a year.

Strawberry

5. Ecological prevention and control

Controlling the room temperature and humidity of the shed can effectively control the occurrence of powdery mildew. First of all, double-row ridging and transplanting and full-film mulching techniques should be adopted to increase the ground temperature, reduce the temperature difference between the greenhouse and the greenhouse, reduce dew and enhance the light. The second is to establish drip irrigation or under-film watering facilities, if there is no under-film watering facilities, should use water scientifically, do not flood irrigation, based on the principle of "better dry than wet". Ventilation should be strengthened to reduce the relative humidity in the shed. The ideal relative humidity in the greenhouse is about 60% in the flowering and fruit setting stage and about 70% in the fruit expansion period.

6. Chemical control

The main results are as follows: 1) the prevention and control of strawberry powdery mildew should be emphasized in the appropriate period, starting from the seedling stage, the weak seedlings and diseased seedlings should be pulled out in time in the seedling stage of strawberry stolon, and the disease should be prevented for 2 to 3 times after planting, with an interval of 7-10 days.

2) the right medicine can choose 2000 times solution of 25% fenuoning wettable powder, 600x solution of 75% chlorothalonil wettable powder, 1000ml 1500x liquid of 10% Shigao water dispersible granule, 12.5% nitrilazole EC 1500m 2000x liquid, 50% carbendazol wettable powder 800x liquid, 50% polysulfide suspension emulsion 500g 600 times, 4% agricultural antibiotic 120 water agent 600g 800 times. When using medicine in continuous rainy weather, you can choose chlorothalonil fumigant.

3) Scientific use of drugs. Spray should be uniform and thoughtful, leaf surface, leaf back should be sprayed, and should pay attention to the alternate use of prevention and control agents to prevent resistance.

4) safe use of drugs. It is necessary to select safe, efficient and low toxic agents for control. Strawberries in the greenhouse are very sensitive to pesticides, and all kinds of chemicals should be sprayed according to the low limit concentration, and should not be mixed with other pesticides and micro-fertilizers to avoid drug damage; generally do not use drugs during flowering, otherwise it is easy to produce abnormal fruits; pollution-free biological pesticides should be selected for control from fruit expansion to harvest. The safety interval of pesticides should be strictly enforced. Generally, the use of pesticides should be stopped 7 days before harvest and pesticide residues should be controlled.

Early detection of the disease, find out the cause, symptomatic treatment, strawberries can still continue to blossom and bear fruit. In short, if you are in accordance with the growth requirements of strawberries to raise it, usually do a good job of basic maintenance, strawberries will not be infected with disease.

What are the common diseases and insect pests of strawberries

Strawberries are mainly eaten fresh, and no pesticides can be used during fruit ripening. Therefore, the principle of prevention and comprehensive control should be carried out in strawberry production. There are many kinds of strawberry diseases and insect pests, among which the more serious diseases are strawberry gray mold, powdery mildew and snake eye disease, and the more serious pests are red spiders, aphids and grubs, which seriously affect the quality and yield of strawberries. The following is an introduction to the common diseases and insect pests of strawberry and their control methods.

Strawberry Botrytis cinerea

Harmful symptoms: strawberry gray mold mainly harms flowers, leaves and fruits, as well as leaves and petioles. Most of the disease starts from the flowering stage, and the pathogen initially infects the failed flowers or weaker parts, causing the flowers to show light brown necrosis and rot, resulting in a gray mildew layer. Most of the leaves invade from the edge of the old yellow leaves at the base, forming a "V" shaped yellow-brown spot, or infecting along the place where the petals fall, forming a near-round necrotic spot, on which there are not obvious wheel patterns and sparse gray mold. Most of the fruit infection starts from the residual petals or near or in contact with the ground, initially showing water-stained grayish brown necrosis, and then the color becomes darker, the fruit decays, and a dense gray mildew layer is produced on the surface. Petiole disease, showing light brown necrosis, dry shrinkage, sparse gray mold is produced on it.

Prevention and control methods:

1. Disease-resistant varieties were selected.

2. Agricultural prevention and control, improve cultivation management and implement crop rotation. Deep ploughing before planting to reduce the source of bacteria. Planting with high border and plastic film mulching should be carried out to prevent the fruit from touching the ground directly. Select the land with high and dry terrain and good ventilation. Reasonable close planting. Avoid applying too much nitrogen fertilizer. Strengthen field management, remove old leaves, withered leaves, diseased leaves and diseased fruits in time, and take them out of the garden to burn or bury them deeply, reduce infection sources and use drip-free greenhouse film.

3. Before chemical control and planting, 25% carbendazim wettable powder 75-90 kg per hectare was applied and raked evenly into the soil to eliminate residual bacteria and disinfect the soil. At the initial stage of the disease, we can use 1500 times of Shjiale 40% suspension, 1200 times of 50% Nongliling wettable powder, 65% carbendazim, 5% carbendazim, 50% carbendazim wettable powder, 45% Tekedo emulsion and 10% Polaroid wettable powder. Spray, spray once every 7 days, a total of 3 times 4 times, focus on spraying flowers and fruits. In the protected area, 6.5% carbendazim dust agent 1 kg / mu is sprayed, or 20% Teke multi-smoke agent 0.3 kg / mu is used for fumigation, the control effect is better.

Strawberry powdery mildew

Harmful symptoms: mainly harmful to leaves, petioles, flowers, pedicels and fruits. When the leaves were infected, white nearly round star-shaped small powder spots were produced on the back of the leaves at the initial stage, and then expanded around into continuous white powder spots with inconspicuous edges. In severe cases, the whole leaf was covered with white powder, and the leaf edge curled up and deformed, and finally the diseased leaves gradually withered and yellow. The flowers and buds are infected, the petals are pink, and the buds cannot open. When the fruit is infected, the young fruit can not expand normally, and in the later stage, the fruit surface is covered with a layer of white powder and poor coloring. The optimum temperature for bacterial infection was 15-25 ℃, and it was not conducive to the disease when it was lower than 5 ℃ or higher than 35 ℃. When the relative humidity is above 80%, low humidity can also germinate, especially when high temperature and drought and high temperature and high humidity occur alternately, and it is easy to be popular when there are a large number of bacteria.

Prevention and control methods:

1. Disease-resistant varieties should be selected according to local conditions.

2. Reasonable close planting of agricultural prevention and control to maintain good ventilation and light transmission conditions. Drainage in time after rain and strengthen the management of water and fertilizer. Cultivate healthy plants. Strengthen the field management, remove the old and diseased leaves in time, and bury or burn the withered branches and residual leaves in the field.

3, chemical control in the early growth of strawberries, when not infected with powdery mildew, 80% mancozeb wettable powder 800 times liquid, 75% chlorothalonil wettable powder 600 times liquid spray protection.

In the early stage of powdery mildew, the medicament can be used in time to prevent and cure powdery mildew, 15% trimethoprim wettable powder 1500 times, 50% carbendazim wettable powder 500 times, 70% methyl thiophanate wettable powder 800 times, 40% polysulfide suspension 3000 times, 40% DuPont Fuxing EC 8000 times, 50% Baogong wettable powder 2000 times, 47% Carinone 600 times.

At present, the most effective way of prevention and control is to use sulfur fumigator.

Strawberry snake eye disease

Strawberry snake eye disease, also known as strawberry white spot disease, leaf spot disease, widely distributed in strawberry cultivation areas in China, the incidence rate can reach 40% to 60%.

Harm symptoms: the main harm to leaves, mostly occurred in the old leaves, petiole, fruit pedicel, calyx, berries can also be damaged. The leaves are infected, initially forming small and irregular red to purplish red spots, and then gradually expanding into round or oblong spots with a diameter of 2 to 5 mm, with gray-white center and purple-brown edges, resembling snake eyes, and many small black spots are produced on the disease spots in the later stage. when the damage is serious, many disease spots merge into large disease spots and the leaves die. After the fruit stalk and calyx are infected, irregular yellow-brown to black-brown spots with darker edges are formed, which are easy to disconnect from the disease when dry. When the fruit is infected, the seeds on the berries are damaged, and the damaged seeds, together with the surrounding pulp, turn black. The bacteria like the humid environment, and the optimum temperature is 18-22 ℃. The disease is serious in wet plots with continuous cropping, poor drainage, extensive management or weak plant growth.

Prevention and control methods:

1. Select resistant and disease-tolerant varieties according to local conditions.

2. Agricultural prevention and control

Reasonable crop rotation, controlled application of nitrogen fertilizer, to prevent excessive growth, appropriate sparse planting, removal of old and withered leaves, improvement of ventilation and light transmission conditions, timely cleaning of the countryside after harvest, and centralized burning of residual and diseased leaves.

3. Chemical control

At the initial stage of the disease, 50% copper succinate (DT) wettable powder, 65% Dysen zinc wettable powder, 77% copper hydroxide wettable particle powder, 50% carbendazim wettable powder, 70% methyl thiophanate wettable powder and 40% fluorosilazole EC were sprayed at an interval of 10 days for a total of 2 times.

Red spider

Harmful characteristics: also known as cinnabar spider mite, panonychus mite. It is an important pest of strawberry cultivated in protected area, and it is widely distributed all over the country. Food habits are miscellaneous, with adult mites and nymphs on the back of the leaves to absorb plant juice, when the occurrence of a large amount of gray leaves, growth pause, and formed a silk net on the plant, seriously causing the leaves to scorch and fall off, such as burning strawberries. The older the strawberry leaves are, the higher the nitrogen content is, and red spiders are easy to occur. With extensive management, the plant growth is weak and the harm is aggravated.

Prevention and control methods:

The main results are as follows: 1. Agricultural control is carried out in early spring to remove weeds in fields and fields and reduce the source of insects. After the vegetables are harvested, the dead branches and leaves are removed and burned. During the period of strawberry seedling cultivation, insect leaves, old leaves and withered yellow leaves were removed in time and burned.

2. The ideal control effect can be achieved by chemical control application of 40% diclofenac EC 1000 × 1500 times, 20% mifenjing wettable powder 2000 times, 15% paraben EC 2000 times, 1.8% acarine EC 60008000 times and so on.

Aphids

Harm characteristics: strawberry producing areas often occur. During the initial flowering period of strawberry bolting, a large number of aphids move into strawberry field, live on the petiole, leaf back, tender heart, inflorescence and flower buds of strawberry tender leaves, absorb juice, cause tender buds to atrophy, tender leaves wrinkle and curl, deformed, can not spread leaves normally. Aphids are the main media for the transmission of viral diseases, and the losses caused by aphids are far greater than those caused by their own harm.

Prevention and control methods:

1. Spraying pesticides is the most effective measure to control aphids at present, which can not only control aphids, but also effectively prevent virus diseases. There are many natural enemies of aphids, such as ladybugs, lacewings, aphid flies, parasitic wasps and so on. Broad-spectrum pesticides should be used as little as possible to protect natural enemies. The main medicaments are 2500 times of 50% deltamethrin EC, 4000 × 5000 times of 10% aldicarb, 2000 × 3000 times of aldicarb, 2000 times of 20% deltamethrin EC, 2.5% deltamethrin EC and 2.5% pyrethrum (pyrethroid) EC 3000 times, etc.

2. The winged adult aphid induced by yellow board has a strong tendency to yellow and orange, and a yellow plate is set around the strawberry field. That is, the plastic film coated with orange 30 × 50 square centimeters, then coated with sticky oil, inserted into the field or hung 0.5 meters above the ground, put a piece at intervals of 3 to 5 meters, so that a large number of winged aphids can be killed.

3. Silver film to avoid aphids can be covered with silver gray plastic film to prevent aphids from migrating to strawberry fields.

4. To make use of natural enemies, we should choose pesticides with high efficiency and low toxicity, reduce the use of pesticides as much as possible, protect the natural enemies of aphids, and use natural enemies to control the number of aphids. It can also be artificially raised or captured by natural enemies, released in the ground and controlled by aphids.

5. Clean the countryside in time, remove the old leaves of strawberries and eliminate weeds.

Grub

Harm characteristics: grub is a general term for all kinds of beetle larvae. Grubs gnaw on germinated seeds and bite off the roots of seedlings, resulting in the death of the whole plant and, in serious cases, lack of seedlings and broken ridges.

Prevention and control measures:

1. Agricultural measures: reasonable arrangement of stubble and rotation. Farm manure should be fully mature so as not to bring larvae and eggs into the vegetable field or attract adults to lay eggs. With the application of ammonium bicarbonate, ammonium humate, ammonia, ammoniated calcium phosphate and other chemical fertilizers, the ammonia emitted can repel grubs and other underground pests. Timely autumn ploughing, turn some adults and larvae to the surface, make them air-dried, freeze to death or be preyed on by natural enemies, and kill them mechanically.

2. The navel grubs should be screened out before applying farm manure. After planting, it is found that the larvae in the soil can be dug out when the seedlings are killed, and the larvae can be captured or killed on the crops where they stop by making use of the false death of adults.

3. Poison bait is used to trap and kill 5 kg of bait such as 25% parathion or phoxim capsule 150g 200g mixed with millet, or 50% parathion EC and 50% phoxim EC 50g 100g mixed bait 3kg / mu, scattered in the seed ditch, a good control effect can be obtained.

4. In areas with conditional physical methods, black light can be set up to trap and kill adults to reduce the number of grubs.

5. Biological control uses brown insectivorous gadfly, beetle black soil wasp, Beauveria bassiana and so on.

6. The soil was treated with 50% phoxim EC 2000.250g per mu, sprayed 10 times with water on 250kg fine soil to make poisonous soil, applied along the ridge, then shallow hoe, or removed the poisonous soil in the planting ditch or the ground, and then ploughed or mixed into the barnyard manure to apply. The poisonous soil was made by mixing 2% methyl isosinophos powder with 2kg / mu of fine soil and 25kg / mu of fine soil. The soil was treated with 3% isofenphos-methyl granules, 3% Weimudan granules, 5% phoxim granules or 5% Dianong granules, 2.5 kg / mu.

Common diseases and insect pests of strawberry in greenhouse and their control countermeasures Strawberry (scientific name: Fragaria × ananassa Duch.), perennial herb, 10-40 cm tall. Stems below leaves or subequaling, densely opened. Show yellow pilose. Leaves Ternate, leaflets short-stalked, thick, Obovate or rhombic, dark green above, few glabrous, pale green below, sparsely hairy, densely along veins; petiole densely covered with yellow pilose. Cymes, leaflets with a short stalk below inflorescence; flowers bisexual; sepals ovate, slightly longer than epicalyx; petals white, suborbicular or Obovate-elliptic. Aggregate fruit large, persistent sepals erect, adherent to fruit; achene apex ovate, smooth. The florescence is from April to May and the fruiting period is from June to July.

Planting strawberries in greenhouse can change or control the environmental conditions of their growth and development, overcome unfavorable factors, make them blossom and bear fruit normally, harvest in advance and supply the market out of season. Greenhouse cultivation has the characteristics of low investment, quick effect, high yield and good benefit. 1 500 kg of land per 667 square meters is more than 1 times higher than that in the open field, and the output value is more than 10 times higher than that in the open field. In order to prolong the supply period of strawberries and meet the demand of annual supply, four cultivation forms are commonly used: ①-facilitated cultivation (maturing from November to December in late autumn and early winter), ② semi-promoting cultivation (maturing from February to March), ③ super-promoting cultivation, and ④ inhibition cultivation. Although the greenhouse has many advantages, it also has some disadvantages. Because of the high temperature and humidity in the greenhouse, it is easy to create very favorable environmental conditions for the occurrence of diseases and insect pests. It is particularly important to strengthen the comprehensive prevention and control of diseases and insect pests, and it has become the key link to realize the high and stable yield of strawberries in greenhouse. Leaf spot disease, also known as snake eye disease, mainly harms leaves, petioles, fruit stalks, tender stems and seeds. Small dark purple spots are formed on the leaves, which are enlarged to form near-round or oval disease spots, with purple-red-brown edges, gray-white center and slightly fine wheels, so that the whole disease spot is snake-eye-like, and small black grains are not formed on the disease spot. Prevention and control measures: timely removal of diseased leaves, old leaves. The initial stage of the disease with 70% chlorothalonil wettable powder 500-700 times liquid, ten days later spray again. Or spray 75 kg of water with 70% mancozeb wettable powder, 200 grams per 667 square meters. Powdery mildew is mainly harmful to leaves, but also to flowers, fruits, fruit stalks and petioles. The leaves are rolled up in the shape of a spoon. The flower buds and petals are purplish red, can not bloom or bloom completely, the fruit is not inflated, is slender, and the young fruit loses luster and hardens. Near-ripening strawberries will lose their commercial value when they are damaged. Control measures: focus on spraying Baume 0.3 degree stone sulfur mixture in and around the disease center strain. After harvest, the leaves of the whole garden were cut and sprayed with 1000 times of thiophanate methyl, 800 times of methamphetamine and 5000 times of Teflin. Botrytis cinerea is the main disease after flowering, which can occur on flowers, petals, fruits and leaves. Brown spots were formed on the fruit during the expansion period, and gradually enlarged. Botrytis cinerea caused the fruit to soften and rot, which seriously affected the yield. Control measures: from budding to flowering, spray with 300 times of 25% carbendazim wettable powder, 800 times of 50% carbendazim wettable powder, and 500-700 times of 50% prophylaxis. Root rot starts from the lower leaves, the edge of the leaves become reddish brown, gradually wither upward, and even die. The pillar begins to turn dark brown and rotten in the middle, and the central column of the root is red. Control countermeasures: before transplanting strawberries, use 40% asparagus green powder 600 times liquid, pour on the border, and then cover the soil, flatten and transplant, in order to effectively kill the bacteria in the soil, reduce the number of bacteria in the field, and reduce the chance of infection. Verticillium wilt is a soil disease. The main symptoms are deformity of young leaves, yellowing leaves and rough surface of leaves. Then the leaf margin browned and withered inward until it died. Control measures: strict introduction of disease-free plant planting; shortening the renewal life; using chloropicrin 13. 5-20 liters or solar film irrigation for soil disinfection; those who have developed the disease must be removed and burned. Aphids do harm to strawberries because the absorption of juice hinders the growth of the fruit, but also because the aphids expel nectar and pollute the leaves and fruits. In addition, aphids are also vectors of virus transmission. Control measures: timely removal of old leaves, clean up the field, eliminate weeds. Spray 50% aphid spray 2000 times before flowering, a total of 1-2 times. The main victims of red spider strawberry are red spider and yellow spider. In particular, red spiders do more harm, and small gray spots appear when the leaves are damaged at the initial stage, and then gradually expand, so that the whole leaves are covered with broken white patterns, yellowing and curling, plant dwarfing and atrophy, seriously affecting the growth. Control measures: when the inflorescence first appears, it can be sprayed with 0.3 degree stone sulfur mixture and sprayed again every seven days. Before fruit picking, 5000-8000 times of fenvalerate with low residual toxicity was sprayed twice with an interval of five days. Pay attention to the prohibition of pesticides two weeks before fruit harvest.