The loofah disease should be timely controlled by pesticides. The Chinese pesticide net Xiaobian will analyze the main disease prevention methods for you:
(1) Loofah downy mildew: mainly damages the leaves, the diseased leaves first appear irregular yellowish to fresh yellow lesions, and then expand into polygonal yellow-brown lesions. When wet, the purple black mold layer appears on the back of the lesions, and the late lesions Connected into pieces, the leaves die, severely reduced production. The pathogen of the disease is the Cuban pseudo-frozen fungus, and the bacteria overwinter on the sick body. Low temperature and rain, high air humidity, large temperature difference between day and night, poor drainage in the field, are conducive to the onset. In the field, germs spread through the wind and rain.
(2) Loofah anthracnose: The ring pattern is the main feature of the disease in the late stage of the disease. It is a pale yellow near-round small spot at the beginning of the disease, and then becomes dark brown and has a wheel pattern. The center of the lesion is easy to perforate and rupture when dry. In severe cases, the leaves die early, causing the plants to wither and die; the melons and the petiole are susceptible, the lesions are oval, dark brown depression, and when the humidity is high, the lesions overflow pink mucus. The pathogen of the disease belongs to the semi-infected sub-genus, the genus Cucurbitaceae, and the high temperature and high humidity, cloudy and rainy is conducive to the occurrence of the disease. The pathogens overwinter on the diseased bodies with mycelium and conidia disks.
(3) Loofah powdery mildew: mainly harmful leaves, petioles and stems. The initial round or irregular white spot on the front and back of the blade is contiguous, the leaves turn yellow and the leaves are dry. In the early stage of the disease, it is not easy to find, and it is difficult to prevent and control after severe disease. The pathogen of the disease is a melon fungus. The pathogens overwinter with hyphae or conidia on the host, becoming the primary source of infection in the following year, and the conidia are spread by airflow or rain.
(4) Loofah disease: It is mainly harmful to fruits, and sometimes stems and leaves are also affected. The incidence of fruit began from the flower pedestal, the lesion was sag, the water stain was dark green at first, and the melon strip was soft and rotted when the humidity was high, and there was white mildew. The stem vines are mainly water-stained at the beginning of the tender stem or internodes, and the whole section is wet and rot, dark brown. The disease of the leaves is initially water-stained yellow-brown spots. When the humidity is high, white mold layer is formed. When dry, it is blue-white and easily broken. The pathogen is a Phytophthora parasitic fungus, which is spread over the winter by seeds or oospores on seeds and wards.
(5) Loofah virus disease: Symptoms are light green and dark green mottled or faded small ring spots after sensation of young leaves. Old leaves show yellow ring spots or yellow-green interphase leaves, leaves are twisted or deformed, and later produced. Dead spots. After the onset of the fruit, it is spirally deformed or slightly distorted, with chlorotic lesions. In addition to aphid infection, the virus can also transmit poison by contact friction. The weather is dry and high temperature, which is conducive to the occurrence of aphids, and the occurrence of viral diseases is also serious.
Pesticide control program:
(1) Prevention and treatment of viral diseases. Can be used 20% virus A powder 500 times solution, or 1.5% phytopathic 1000 times liquid spray control, every 7 days to prevent once, even spray 2 to 3 times. In order to prevent the spread of viral diseases, timely use 10% imidacloprid wettable powder 2000 times solution, or 50% avoiding misty wettable powder 10 grams per mu spray to prevent and cure melon, which has a good preventive effect on the virus.
(2) Prevention and control of powdery mildew. 40% rich star emulsifiable oil 8000 times solution, ah 12.5% ​​tepazole powder 1500 times liquid, or 20% powder rusting emulsifiable oil 1000 times liquid spray control, every 5 to 7 days of prevention and control, even prevention 2 to 3 times, the effect is better it is good.
(3) Prevention and treatment of epidemics. It can be controlled by spraying 58% of Rydmir powder 500 times, which can control the occurrence and spread of the disease.
(4) Prevention and treatment of anthrax. 75% chlorothalonil WP 600 times solution, or 50% thiophanate 800 times solution, or 60% daikon zinc WP 500 times solution spray, can be controlled every 7 to 10 days, Even 2 to 3 times, the effect is obvious.
(5) Prevention and treatment of downy mildew. Pesticide network recommendation, can choose 58% Rydmir Mn-Zn wettable powder 800 times solution, or 72% Plex water 600 times solution, or 25% Phytophthora WP 500 times liquid spray control, every 7 days Control once, even 2 to 3 times, the control effect is better.