Summary of common diseases of pepper in early spring

Recently, the continuous overcast and snowy weather has seriously affected the normal growth of chili and sweet pepper. According to what the author learned on March 5 in Jitai Town, Sunjiaji Street Office, Yangjiacun and other pepper growing areas in Shouguang City, pepper and sweet pepper in the latest fruiting period are more common due to bad weather. There are mainly gray mold and Sclerotinia sclerotiorum-brown watery spots appear on the top or pedicel of young fruits, sunken rot, and gray mold layers appear on the surface of the spots. Sclerotinia sclerotiorum develops from the stalk to the whole fruit, showing water-stained rot, light grayish brown, and similar symptoms in other parts. Blight-most of them first catch the disease from the pedicel, showing water-stained gray-green spots, then quickly turn brown and soft rot, and the flesh turns brown and even the seeds turn brown. Due to the continuous rainy weather and high air humidity, a sparse white mildew layer grows on the surface of the disease spot. Other parts, such as stems, branches and leaves, often have watery brown spots. Anthracnose-especially colored sweet peppers, are susceptible to the disease when the fruit is nearly ripe. At the beginning, it shows a water-stained yellow-brown round spot, the center is grayish brown, there are slightly raised concentric patterns on it, and there are often small black spots. When the air humidity is high, there is often a red sticky substance on the surface of the disease spot; when dry, the disease part shrinks into a film, which is easy to break and expose seeds. In this issue, this newspaper summarizes the common diseases of chili peppers for reference by vegetable farmers.

Grey mold disease

The disease can occur in both seedling stage and adult stage. When the seedlings are infected, the cotyledons die at the apex, then spread to the young stems, which constricts and becomes thinner, and is easy to break and die from the disease. The seedlings with serious disease died in pieces, and some of them had the possibility of destroying the shed. True leaves infected with semicircle to nearly round light brown ring spots, in the later stage, the leaves or stems can grow gray mold, and the pathogenic parts rot. When the adult plant is infected with the disease, a large water-immersed spot is formed at the edge of the leaf, and then browning to form an oval or nearly round light yellow wheel spot, which is densely covered with gray mildew layer, which seriously causes large spots and the whole leaf dries up. When the fruit is infected, the water-immersed brown disease spot first occurs around the pedicel of the young fruit, which is dark brown after expansion, sunken rot, and irregular wheel-like gray mildew is produced on the surface.

When the greenhouse is low temperature (20-30 ℃), high humidity (air humidity up to 90%), poor ventilation, excessive planting density, improper management, poor plant disease resistance and so on. The pathogen overwinters in the diseased body and soil, spreads through airflow irrigation water and farming, and invades from the wound aging or dead tissue.

The prevention and control method is that the greenhouse should be ventilated in time, watering should be arranged in the morning on a sunny day, and the amount of water should be properly controlled to avoid flooding and excessive irrigation.

At the initial stage of the disease, 50% Sukeling wettable powder 1500 times, 50% Nongliling wettable powder 1000 times, 40% polysulfide suspension can be sprayed at the initial stage of the disease. 250g per mu, or 5% chlorothalonil dust, 1kg per mu, but at this time, we must pay attention to timely ventilation on the second day of the smoke shed. To avoid drug damage but affect the normal growth of sweet pepper.

In addition, when the sweet pepper is dipped in the flower, 0.1% of 50% Sukeling wettable powder and 50% prohydantoin wettable powder can be added to the growth regulator to prevent the occurrence of Botrytis cinerea.

Epidemic disease

It can occur at both seedling stage and adult stage. The disease in the seedling stage is mainly harmful to the rhizome, making the rhizome tissue rot, the disease part constricted, the seedlings lodging, causing wet rot, withering and death. After planting, the leaves were infected, the disease spots were round or nearly round, showing dark green waterlogging, and the rapid expansion made some or most of the leaves soft rot, and the disease spots became light brown after drying, and the leaves fell off. The waterlogged disease spot was produced in the stem, which became longer after expansion, the disease part became dark brown in the later stage, the cortex softened and rotted, the branches and leaves above the disease part withered quickly, and it was easy to break from the disease part. The fruit infection begins with the pedicel, first appears water-immersed spots, dark green, then the disease spot expands, the pericarp becomes brown and soft rot, and the fruit falls off or loses water to become a stiff fruit, which remains on the branch.

The disease is caused by Phytophthora capsici. Pepper could be infected when the average temperature was more than 10 ℃, and the disease was the fastest at 27-30 ℃. It could be infected under the conditions of less sunshine, high air humidity and low soil evaporation. Especially in flood irrigation, it is more likely to cause disease occurrence and epidemic. The pathogen can overwinter on the diseased body and seeds, and directly infect the stem base of pepper (sweet pepper) plant in the coming year. Blight is a destructive soil-borne disease of pepper (sweet pepper) cultivation in greenhouse.

The method of prevention and treatment is to choose disease-free new soil to raise seedlings or disinfect them on the bed. Covering the seedling bed with seedling bacteria enemy soil, the specific ratio is 6 shovel soil plus a packet of 25 grams of seedling bacteria enemy, mixed and sprinkled on the surface of the seedling bed to do floating soil, or spray 72.2% of Pulek 600 times in the seedling bed, can prevent the occurrence of seedling stage quenching disease.

Strengthen agricultural management, pay attention to ventilation and replenish light to prevent excessive humidity. Choose to water in the morning on a sunny day, raise the temperature and reduce humidity after watering, avoid high temperature and humidity, pull out the diseased plants in time and remove them from the shed for centralized treatment.

Chemical control is that 80% mancozeb wettable powder can be sprayed 600 times after planting, once every 15 days. At the initial stage of the disease, 40% ethyl phosphate aluminum wettable powder 200 times liquid or 75% chlorothalonil wettable powder 600 times liquid, or 64% poison alum wettable powder 400 times 500 times liquid, 40 kg per mu, once every 7 to 10 days, for 2 times in a row. 45% chlorothalonil smoke remover can also be used in the greenhouse, 250 grams per mu, or 5% chlorothalonil dust agent, 1 kg per mu, about once every 9 days, continuous prevention and control for 2 or 3 times.

Anthrax

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