Harmful symptoms and control methods of cucumber blight

Cucumber blight can be infected from the seedling stage to the adult stage, and the seedlings begin to appear dark green and water-immersed rot on the tender tip, gradually drying up and forming a bald tip, which mainly harms the base of the stem and the nodes of the tender stem at the adult stage, and begins to be soaked in dark green water, then softens, constricts obviously, and the leaves above the affected parts gradually wither. Let's take a look at the prevention and control methods of cucumber blight.

Occurrence regularity of cucumber blight

Cucumber blight is a fungal disease, which overwinters with disease residues in soil or manure. The conditions in the coming year are suitable for sporangia to grow through wind and rain, irrigation and water droplets to spread. The appropriate temperature of the disease is 28 to 30 degrees Celsius, and the disease is easy to occur and spread quickly with large rainfall, more rainfall or more shallow water. Therefore, the disease is serious under the conditions of low-lying terrain, poor drainage and high humidity.

Conditions for occurrence of cucumber blight

The pathogen overwintered mainly by mycelium, oospore and chlamydospore in soil or manure, and spread by wind, rain and irrigation water. The optimum temperature for the disease was 2830 ℃, and soil moisture was an important factor affecting the epidemic degree of the disease. The epidemic disease is easy to spread and the harm is serious in the years with high temperature, heavy rainfall and more rainy days in summer. In addition, low-lying terrain, poor drainage, continuous cropping and other prone to disease. When protected cultivation, at the turn of spring and summer, after opening the vents in front of the greenhouse, it is easy to get sick quickly.

Control methods of cucumber blight

1. Agricultural measures: select disease-resistant varieties, such as Jinchun 3, Jinza 3, Jinza 4, Zhongnong 1101, Longzahuang 5, Zaofeng 2 and so on. Yunnan black seed pumpkin was selected as rootstock to raise seedlings by grafting. High border cultivation was used to cover plastic film to reduce the chance of pathogen infection to the plant. Avoid flooding and avoid excessive moisture in the soil and air. When cultivated in the open field, the stagnant water in the field should be discharged in time in the rainy season, and the central diseased plant should be pulled out in time.

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2. Disinfection treatment: the effective method of seed disinfection is to soak the seeds with 25% metalaxyl wettable powder 800 times solution for 30 minutes and then accelerate germination and sow seeds. The method of soil disinfection in the seedbed or shed is to mix 8 grams of metalaxyl wettable powder with soil on the seedbed per square meter, and spray the ground with 750 times of metalaxyl wettable powder before planting in the protected field.

3. Chemical control: the key to the prevention and control of cucumber blight in the open field is to start spraying one week before the arrival of the rainy season, once every 7 days, three times in a row. The available agents are 64% alum wettable powder 1000 times, 25% metalaxyl wettable powder 600 times, leaf mildew fungicidal wettable powder 1200-1600x, 50% nail cream copper wettable powder 600x, etc. The practice shows that the prevention effect is very good when sprayed with 500 times of 70% mancozeb wettable powder or 200 times of Bordeaux solution with 0.80% Bordeaux.

Harmful symptoms and control methods of balsam pear blight

Balsam pear blight is harmful to stems, leaves and fruits, with the base of vines and tender vines suffering more, the pathogen is flagellate subphylum fungus parasitic Phytophthora, autumn cucumber is more common in the north, and spring cucumber in central and southern China is more common, in addition to cucumbers, it is also harmful to winter gourd, zucchini, vegetable gourd, pumpkin, watermelon and other crops. Let's take a look at the prevention and control methods of balsam pear blight.

Harmful symptoms

Balsam pear blight often appears before flowering, and stems and fruits are susceptible to the disease. The leaves lost their luster at first, and at the initial stage they were dark green water-stained spots with irregular shape and inconspicuous edge. a thin layer of white mold could be seen when the humidity was high, and it was bluish white and easy to break when dry. The petiole and vine node appear dark green water-stained soft rot, and the affected part is easy to overflow and shrink. Melon strips are damaged by dark green sunken disease spots, when the humidity is high, melon strips quickly soft rot, suffer from sparse white mold, rot and stink.

Morbidity regularity

The pathogen is mainly mycelia, oospores or chlamydospores left in the soil with the disease remains in the winter, and the seeds can also carry bacteria. The development temperature range of the pathogen was 5-37 ℃, and the optimum temperature was 28-30 ℃. In the range of suitable temperature, the length of rainy season and the amount of rainfall are the decisive factors for the occurrence and epidemic of the disease. the rainy season comes early, the rainy day is long, the rainfall is heavy, the disease is early and the disease is serious. In addition, poor drainage in the field and high soil moisture are easy to induce epidemic disease.

Agricultural prevention and control

Agricultural control of balsam pear blight can be carried out for more than 3 years, and high ridge (ridge) cultivation covered with plastic film can be used to reduce the pathogen of ground water splashing. Reasonable irrigation and control of field humidity. Proper control of watering in the rainy season, timely drainage after rain, so that the rain is dry. Timely watering in the morning, flooding is strictly prohibited when watering, and should be carried out in the afternoon or evening on a sunny day. More application of organic fertilizer can promote plant growth, deep roots and luxuriant leaves, and improve resistance. Plant adjustment should be carried out in time to prevent overdense growth and poor ventilation and light transmission. Remove the diseased leaves and burn them at any time.

Drug prevention and treatment

For the drug control of balsam pear blight, 25% Ruidu wettable powder 800 times, 80% Dysen zinc wettable powder 600 times, 64% alum wettable powder 500 times 600 times, 40% aluminum ethyl phosphate wettable powder 300 times 400 times, 80% Xinwansheng wettable powder 500 times 600 times, 72.2% Purek water agent 400 times, 50% potassium cream copper wettable powder 600 times alternately Spray once every 5 to 10 days for 3 times in a row. Spray should be thoughtful and meticulous, and all leaves, fruits and nearby ground should be sprayed.

Causes and control methods of cucumber blight in greenhouse

What are the symptoms of cucumber blight in greenhouse? recently, many vegetable farmers reacted. Cucumber stems planted in greenhouse began to have gum. At first, the gel was clear, then turned yellowish, and the melon seedlings were quickly broken. After the cucumber stem is glued, when it is serious, the melon strips also appear glue. This is the symptom of cucumber blight. The following editor shares the prevention and control methods of cucumber blight in greenhouse.

Causes of cucumber blight in greenhouse

There are many causes of cucumber stem gum, but the recent phenomenon of cucumber stem gum in greenhouse is mainly caused by cucumber blight, which should be paid special attention to by melon farmers. Cucumber blight mainly harms leaves, stems and melon strips, especially young stems and tender tips. The disease of the leaves showed dark brown water-immersed spots and then expanded into near-round spots, which expanded rapidly when wet, often causing whole leaf rot, dark green at the edge of the spot and light brown in the middle when dry. The damaged part of the stem was flooded, dark green rot and obvious constriction, resulting in glue flow, causing the branches and leaves above the affected part to wilt and die, but the vascular bundle did not change color. Melon strips were damaged by water-stained dark green nearly round sunken disease spots, and the disease developed rapidly when the humidity was high in the shed. In the later stage, the disease secreted milky white glue, gradually changed to amber, and then softened and soft rot.

Control methods of cucumber blight in greenhouse

In agricultural measures, black-seeded pumpkin can be used as rootstock for grafting. High border cultivation was used to cover plastic film to reduce the chance of pathogen infection to the plant. Avoid flooding and avoid excessive soil and air humidity. Remove the diseased plant in time after finding the central diseased plant.

Medicament prevention and cure can choose 64% poisonous alum wettable powder 600x liquid or 25% metalaxyl wettable powder 1000 times liquid, 58% metalaxyl ·manganese zinc wettable powder 800x liquid irrigation root, 5-7 days once, continuous irrigation 3 times.