Harmful symptoms and Control methods of Cucumber Leaf Blight

Cucumber leaf blight mainly harms leaves, the symptoms of young leaves are not obvious, growing leaves appear yellowing areas, abnormal water-immersed chlorotic spots, gradually enlarged into near-round or polygonal brown spots, 1mm in diameter, surrounded by faded green halos, the back of diseased leaves is very easy to produce small bright veins in the early morning or cloudy days, let's take a look at the prevention and control of cucumber leaf blight.

Incidence regularity of cucumber leaf blight

The pathogen overwintered mainly with the mycelium in the soil with the disease residue, and produced conidia in the next spring, which were infected by airflow, and then produced conidia on the diseased leaves for re-infection. Weak plants, waterlogging in the field and high humidity are easy to induce the occurrence of the disease.

Incidence characteristics of Cucumber Leaf Blight

The pathogen likes the environment of low temperature and high humidity, the suitable temperature range is 3: 30 ℃, the optimum environmental temperature is 8: 20 ℃, the relative humidity is more than 95%, and the most suitable growth period is from seedling stage to adult stage. The incubation period of the disease is 7-15 days, which occurs only in the protected area, and usually occurs only in the period of low temperature in early spring. When the temperature in the greenhouse exceeds 25 ℃, the disease will be inhibited.

Control methods of Cucumber Leaf Blight

1. Apply sufficient basic fertilizer, drain water in time after rain, and ventilate and penetrate the light between the rows of plants.

2. Collect seeds from disease-free plants and select disease-free seeds.

3. In the protected cultivation shed, the ditch system should be cleaned in time to prevent stagnant water after rain, timely ventilation and ventilation, light watering and frequent watering should be adopted in fertilizer and water management, watering and fertilization should be in the sunny morning, and the shed should be opened in time for ventilation and humidity reduction.

4. Advocate interannual rotation with non-Cucurbitaceae crops in order to reduce the source of pathogens in the field.

5. remove the diseased old leaves in time during the epidemic period of the disease, clean the countryside after harvest, remove the diseased body, and take it out of the field to bury or burn deeply, turn the soil deeply and accelerate the decay and decomposition of the diseased body.

6. Before watering or in the morning of sunny day after rain, Bordeaux solution (1 / 1 / 1 / 200) should be selected for spray prevention, or mancozeb should be selected to prevent and cure the disease at the initial stage.

What symptom is cucumber vine blight? how to solve cucumber vine blight

Cucumber vine blight mainly harms leaves and stems, seriously affects the growth of cucumbers, leaves infect, mostly start from the leaf edge, forming yellowish brown to brown "V" shaped disease spots, on which dense small black spots are easy to break after drying. Today, the editor shares with you what symptoms of cucumber vine blight and how to solve it?

What symptom is cucumber vine blight disease?

Cucumber vine blight is a serious disease to cucumber sown in spring and summer. The disease mainly harms stems and leaves. When the stem and base fall ill, they produce round or fusiform yellowish brown, oil-soaked, slightly sunken disease spots, and amber gelatinous substances, with small black spots scattered on the surface. After the onset of the disease, large round or irregular disease spots appeared in the leaves, which were easily broken in the later stage, and there were dense black spots on the disease spots. The diameter of leaf disease spot is 10-35 cm, and a few disease spots are larger. The diseased leaves are withered and yellow from the bottom up and do not fall off, leaving only 1-2 leaves at the top in severe cases. Vine blight mostly develops from the surface of the stem to the interior, the vascular bundle does not change color, will not die of the whole plant, which is an important difference from Fusarium wilt.

Disease regularity: the pathogen of vine blight is mostly overwintered by conidia or ascospores in the disease residue and soil, mainly by irrigation water and airflow, invading from stomata, water pores or wounds, seed-carrying bacteria can cause cotyledon disease. High temperature and humidity, poor ventilation, partial application of nitrogen fertilizer, flat bed cultivation, flood irrigation, continuous rain, weak plant growth and overgrowth, continuous cropping in successive years are easy to cause disease.

How to solve cucumber vine blight?

1. Select disease-free seeds or retain seeds from disease-free plants in improved seed rotation. Rotation has been carried out for more than 2-3 years.

Second, strengthen management, cultivate strong seedlings, increase the application of phosphorus and potassium fertilizer, enhance plant resistance, strengthen ventilation and light transmission, reduce temperature and humidity, and improve field microclimate.

Third, at the initial stage of drug control, you can choose 75% chlorothalonil wettable powder 600x liquid, or 70% thiophanate wettable powder 1500 times liquid, or 50% carbendazim wettable powder 1500 times liquid, or 45% chlorothalonil smoke remover, 250g per mu each time, or 40% Fuxing EC 800x liquid, once every 7-10 days, 3-4 times in a row.

Control methods of Cucumber Blight

Cucumber blight, commonly known as dead seedlings, often occurs in the middle and later stages of cucumber seedlings, and serious cases can cause seedlings to dry up and die, seriously threatening cucumber yield.

Cucumber blight mostly occurred in the middle and later stages of seedling cultivation. At first, the base of the stem of the seedlings appeared oval or irregular dark brown disease spot, and some of the diseased seedlings wilted during the day and recovered at night, and the disease spot gradually sunken. Light brown arachnoid mold can be seen when the humidity is high, but it is not significant. After enlarged, the disease spot can be around the stem, even the xylem is exposed, and finally the disease part shrinks and dries up, the leaf wilts can not return to its original state, and the seedlings wither and die. The cortex of the underground root turns brown or rotten, but it is not easy to collapse, and the diseased part has a rib or light brown reticular mildew layer.

The main control methods of cucumber blight are as follows: modern seedling raising methods such as nutrition bowl or hole plate seedling are advocated, which can greatly reduce the occurrence and damage of cucumber blight. Add 95% carbendazim 50g or 54.5% carbendazim ·Fu wettable powder 10g, 70% sodium sulfonate soluble powder 100g and 50% carbendazim wettable powder 50% 100g per cubic meter of nutritious soil, mix well with nutritious soil and load into nutrition bowl or seedling tray. To strengthen the observation after seedling emergence, the following fungicides or formulations can be used to control the disease before the disease occurs: 0.5%OS aminooligosaccharides 300 to 500 times + 68.75% oxazolidone ·manganese zinc water dispersible granules 800 to 1000 times; 70% carbendazim wettable powder 800 to 1000 times; 20% fluoramide wettable powder 600 to 1000 times 2000 to 4000 times of allicin EC is sprayed on the seedling bed, once every 7 to 10 days depending on the condition.

When cucumber blight is found in the field, the following fungicides or formulations can be used to control cucumber blight in time. At the initial stage of the disease, the following fungicides or formulations can be used for control: 3500 times of phenylether methyl propyl ring EC, 1200 times of methyl fumarate EC + 75% chlorothalonil wettable powder, 1000 times of carbendazim wettable powder and 1000 times of carbendazim wettable powder. 70% methyl thiophanate wettable powder 500x to 700x + 70% mancozeb WP 800x; 15% carbendazim aqueous agent 500x to 700x + 25% prochloraz EC 800x to 1000 fold; 20% carbendazim water dispersible granules 800 to 1000 times + 70% Dysenlian dry suspension 700x; spray the seedling bed with water, once every 5 to 7 days depending on the condition.