Bacterial wilt, gray mold , sclerotinia, anthracnose and bacterial soft rot can cause the cucumber stem to rot, and the cause should be identified.
The blight of cucumber blight is mostly caused by blight. The symptoms of blight on cucumber stems are that oval or rhomboid white lesions appear at the beginning of the disease, sometimes milky white gelatinous, and severe stem cleavage, and finally stems rot. The leaves are also susceptible to disease, and the bacteria begin to invade from the edge of the leaves and develop inward, showing a "V" shape. The lesions are pale yellow with unclear wheel marks and many small black spots on them.
Cucumber blight is heavier at temperatures between 18 ° C and 25 ° C and relative humidity above 85%, and no water can accumulate in the field. The diseased field should be removed early and the diseased leaves and diseased leaves should be removed.
After the cucumber enters the flowering stage, a large amount of nutrients are absorbed by the fruit enlargement, resulting in weak stems, thin leaves, reduced resistance of plants, and easy infection by pathogens. It can be sprayed with 80% thiram double wettable powder or 75% chlorothalonil WP 500 times, every 7 days to 10 days, and sprayed with 25% prochloraz oil 1000 times after onset.
Botrytis cinerea is a disease of high incidence of cucumber, most of which begins to invade from residual flowers, causing the rot of the melon. These diseased residual flowers and rotten melons are attached to the stems, which can also cause the stems to rot. In severe cases, the stems are broken and the plants die. The pathogen can produce a large number of spores, which are difficult to control as the airflow spreads. Gray mold is prone to occur at a temperature of 20 ° C to 23 ° C and a relative humidity of 90% or more. It can be sprayed with 40% carbendazim WP or 75% thiophanate-methyl WP 500 times, every 7 days to 10 days.
Sclerotium disease stems and stalks are more common in the stems near the ground, and early appearance of pale brown water-stained lesions, soft rot of the diseased stems in the late stage, and white cotton-like hyphae grow. The medullary cavity of the diseased department is hollow or cracked, and the hyphae densely form the black rat fecal sclerotia. The suitable temperature for the onset of Sclerotinia sclerotiorum is 24 ° C, the relative humidity is 85% or more, and the chemical control can be sprayed with 50% ethylene sclerotium water dispersible granules or 50% procymidone WP 500 times, or 50% rot. Mildew smoked smoked shed.
The main vine and petiole of anthracnose disease occur, and the lesions are oval, yellow-brown, and concave. When severe, they are connected to form a piece to surround the main vine, resulting in partial or complete death of the plant. When the relative humidity is above 87% and the temperature is at 24 °C, it takes only 3 days for the cucumber anthracnose to infect from the infection to show obvious symptoms. For non-infected plants, protective pesticides such as chlorothalonil can be used to prevent disease. After the onset, it can be sprayed with 25% bromocarbonitrile wettable powder (500 times solution) or 25% prochloraz cream (1000 times solution) with 80% thiram double wettable powder (750 times solution).
In the early stage of bacterial soft rot, the stems and stalks are water-stained, brown and contracted, and the leaves are wilted from the bottom up, which is more serious at noon, and can be recovered sooner or later. Finally, the whole plant wither and die. The cut stems are squeezed by hand and the milky white pus overflows from the vascular bundle section, and the vascular bundle generally does not change color.
Care should be taken to reduce wound production during management. Before the watering, the vines are dropped, so as to avoid the water content of the stems and vines after watering, which causes the stems to break, which makes the wounds increase and is not easy to heal. Choose sunny afternoon picking leaves, spray the medicine after picking the leaves, reduce the chance of invasion of the bacteria from the wound, can be sprayed with 72% agricultural streptomycin soluble powder 1500 times solution or 3% carbendazim wettable powder 500 times solution. Strengthen fertilizer and water management, reduce root damage and enhance plant disease resistance.
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