What symptoms does balsam pear blight have? What is the method of prevention and control?

Balsam pear is a kind of vegetable with special bitter taste, although it tastes bitter, it has the effect of clearing away heat and detoxification, so it is very suitable for summer consumption. Balsam pear blight is easy to occur in the process of balsam pear planting due to improper management and other reasons, so what are the symptoms of the disease? What is the method of prevention and control?

What are the symptoms of balsam pear blight?

Balsam pear blight is harmful to stems, leaves and fruits. The disease mainly occurred at the base of the vine and the node of the tender vine, which was dark green at first, flooded, then turned light brown, constricted and thinned, the leaves wilted and withered above the diseased part, and the color of the leaves remained green. Leaf disease mostly starts from the leaf edge or leaf tip, the disease spot is dark green, round or irregular, waterlogged, the edge is not obvious, there are faint wheel lines, when wet, the expansion is very fast, soft rot, the disease spot stops to develop when dry, the edge is brown, the middle is bluish white, dry and easy to break. Melon and fruit appeared dark green, nearly round waterlogged disease spot, no obvious edge, quickly extended to the whole fruit surface, wrinkled, soft rot, the surface of gray-white sparse mildew (sporangia and sporangium peduncle).

II. Routes of transmission and conditions of onset

The pathogen overwintered with mycelia and oospores left in the soil with diseased tissue. In the second year, the hyphae or oospores met water to produce sporangia and zoospores, which were transmitted to the bud tube of muskmelon through irrigation water and Rain Water. Attachments and invading filaments penetrated the epidermis into the host, and disease spots appeared in 2-3 days under high temperature and high humidity conditions, and a large number of sporangia were produced, which spread by wind, rain or irrigation water, and carried out repeated infection.

The pathogen produces sporangia in two ways: one is to extract the hyphae from the stomata, the hyphae branches, and the mycelial sporangia grow hard on the branches and form sporangia at the top; the other is to extract short mycelial sporangium peduncles from the stomata and form sporangia at the top. After 48,72 and 96 hours, the average number of sporangia per square centimeter of leaf was 24.2,95.3 and 254.8, respectively. After inoculation, the sporangia released zoospores and germinated or germinated directly into the bud tube after 2 hours of rest on the leaf surface, and began to invade from the stomatal guard cell interspace, the hyphae spread between and within the leaf cells, and protruded from the stomata. Then invade from the stomata or spread on the leaf surface, and the disease appears after a few days of incubation. The occurrence of muskmelon blight is related to the arrival of rainy season sooner or later, the number of rainy days, rainfall and air temperature. When the disease occurs early and the temperature is high, the disease is serious. In general, the disease begins to occur in the rainy season, and when there is heavy rain, it spreads rapidly or causes epidemic. In production, continuous cropping with melons and flat border cultivation are easy to cause disease, long-term flood irrigation, many watering times, large amount of water and serious disease.

Third, what are the prevention and control methods of balsam pear blight?

The main results are as follows: 1. High ridge (border) cultivation covered with plastic film can 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.

2. To prevent and cure the disease in time at the initial stage of the disease. Choose 25% Ruidui wettable powder 800 × 1000 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% Shinwansheng wettable powder 500 times 600 times, 72.2% Purek water agent 400 times 600 times, 50% potassium cream copper wettable powder 600 times alternately, spray once every 5 days for 4 consecutive times. Spray should be thoughtful and meticulous, and all leaves, fruits and nearby ground should be sprayed.