Why do pumpkins get vine blight? How to prevent the occurrence of the disease?

Pumpkin is a very nutritious and healthy food, and it is also one of the anti-cancer foods. Pumpkin not only tastes soft, waxy and sweet, but also has the function of moistening intestines and defecation, which is especially suitable for the elderly and children. There are few diseases in the process of pumpkin planting, but they will still be affected by vine blight. Then why does pumpkin get vine blight? How to prevent the occurrence of the disease?

Why do pumpkins get vine blight?

Pumpkin vine blight, also known as "black rot", is a common disease of melon crops. The disease mainly damages the stems, leaves, petioles and melons of the plant, causing the base of the stem to rot, the melon seedlings to wither and the plants to die, especially the pumpkin cultivated in the open field in autumn.

Vine blight mainly occurred in the middle and later stages of pumpkin growth. Stem vine infection, mostly in the stem node at the base of the stem to produce light yellow oily spots, gradually become grayish white to light reddish brown irregular necrotic spots, the disease often secretes reddish brown colloid. With the development of the disease, the disease spot turned dark brown, and dense small black grains appeared on the surface of the affected area, which was the conidium of the pathogen. In the later stage, the diseased stem shrank or split longitudinally, and even the tissue was necrotic, scattered, such as hemp, and the stems and leaves above the diseased part withered. The leaf is infected, and the V-shaped brown spot is formed on the leaf edge, and the outer edge is yellowish, on which there is no obvious concentric wheel pattern. Petiole infected, initially showed water-immersed rot, and then produced many small black spots, resulting in plant shrinkage and lodging. When the fruit is damaged, it forms a nearly round gray spot with a brown edge, which is about 5mm to 10mm in size; the severe disease begins with irregular chlorosis or yellow spots, then turns gray to brown or black, and finally the bacteria enter the pericarp to cause dry rot, and some saprophytic bacteria take advantage of the opportunity to invade and cause wet rot, endangering the whole fruit. The disease part of vine blight produces small black spots, and the vascular bundles do not change color after cross-cutting of the diseased stem, which can be distinguished from Fusarium wilt.

Pumpkin vine blight is a fungal disease. The pathogen can survive the winter on the diseased remains of the plant and in the soil, or it can be attached to the seeds. The pathogen used asexual conidia as the initial infection source in the field in the coming year, and invaded from the plant wound or stomata with the help of airflow, Rain Water, irrigation water or farming operation, spread and spread in the field for re-infection.

Second, how to control the occurrence of pumpkin vine blight?

One is to reduce the humidity in the shed. During the day, we should pay attention to the time node and reduce the humidity in the shed as much as possible on the premise of ensuring the temperature in the shed.

Second, in usual agricultural operations such as pruning and wiping branches, we should pay attention to avoid the overcast and rainy weather, first deal with the plants that are not diseased, and finally deal with the diseased plants, so as to avoid the spread of diseases caused by human operation.

Finally, there is pharmaceutical treatment. Because pumpkin is a mixture of vine blight and bacterial diseases, it should be mixed with agents to control vine blight and bacterial diseases, for example, the control agents are: 25% difenoconazole, 70% thiophanate, and 50% imipramine manganese salt. Bacterial agents are: mesophyllin, thiamidone, thiocarbamate, etc., it is recommended that the above agents be used alternately.

In addition, where the disease spot on the stem is more severe, you can also use methyl thiophanate or chlorothalonil to adjust into paste and smear it on the spot.