Scientific control of bacterial leaf spot disease of Dutch bean

Dutch bean (scientific name: Pisum sativum var. Saccharatum) belongs to the genus Pea of Leguminosae, annual twining herb, high 90~180cm. Mainly edible young pods, native to the Mediterranean coast and western Asia, Dutch beans tender pods crisp fragrance, high nutritional value. Cooked dried Dutch beans provide twice as much solids, calories, carbohydrates and protein as cooked green Dutch beans, but green Dutch beans contain more vitamins An and C than dried Dutch beans.

Dutch bean, also known as soft pod pea, the lowest temperature of seed germination is 4-6 ℃, the optimum temperature is 16-18 ℃, and the germination rate is low when the temperature is higher than 25 ℃. The ability to tolerate low temperature was the strongest in seedling stage, and the lowest was-4 ℃. The suitable temperature for growth period is 9-23 ℃, and the suitable temperature for flowering stage is 15-18 ℃, which leads to poor fertilization, less pods, lower quality and low yield above 25 ℃. Dutch beans require longer sunshine and strong light. If the growth period is cloudy or the field is not well ventilated and transparent, the plant growth is slender and weak, and the yield of tender pods is greatly reduced. Dutch bean has a wide adaptability to soil, but it is suitable for loose and organic soil with higher ph value than 6.07.2.Rhizobium can fix nitrogen fertilizer in soil, but pay attention to the application of phosphorus and potassium fertilizer. During the whole growing period, moist air and soil moisture are required, especially when the air is dry during flowering and podding, which often leads to falling flowers and pods; long-term high temperature and drought will lead to early hardening of pod fiber tissue and premature maturation, reducing quality and yield.

Dutch bean bacterial leaf spot is one of the main diseases of Dutch bean. Farmers must pay attention to it. Let's take a look at how to control the disease scientifically.

Dutch bean bacterial leaf spot symptoms: also known as pseudomonas vine blight or stem blight, damage to stems, pods and leaves. The seedlings infected with the infected seeds at the seedling stage are infected with the disease; when the infected leaves of the older plants are waterlogged, round to polygonal purple spots, translucent, and when the humidity is high, the back of the leaves is white to cream-colored bacteria pus, and the shiny film is produced under dry conditions, and the leaf spots are withered and become papery; the stems are infected with primary brown stripes; pedicel disease can spread from pedicels to flower organs, causing flower wilting, young pods drying and rot. Pod disease spot nearly round slightly sunken, initially dark green, and then became yellowish brown, bacterial pus, 3 mm in diameter.

The pathogen of bacterial leaf spot of Dutch bean: Pseudomonassyringaepv.pisi (Sackett) Young.eta1. It is said that Pseudomonas clove is a pathogenic variety of Holland bean, which belongs to bacteria. The cell is rod-shaped, with at most one flagellum, no spores, no capsule. Gram staining is negative and aggressive. The size is 0.58 ~ 0.82 × 1.11 ~ 3.28 microns. The colony on the gravy peptone Agar plane was grayish white, the circle was slightly convex, and the edge was wavy. The optimum temperature for bacterial growth was 2830 ℃, the highest was 35,36 ℃, the lowest was 0 ℃, and 50 ℃ killed in 10 minutes.

The transmission route and incidence conditions of Dutch bean bacterial leaf spot: the pathogenic bacteria overwintered in the seeds of Dutch bean and broad bean and became the main source of primary infection in the following year. It is easy to suffer from excessive plant growth, untimely drainage after rain and excessive fertilization, and it is easy to encounter low temperature obstacles in production, especially after freezing injury. It is easy to get sick in out-of-season cultivation.

Scientific control methods of bacterial leaf spot of Dutch bean:

The main results are as follows: 1) to establish a disease-free field and collect seeds from disease-free plants.

2) seed disinfection. Mix seeds with 50% methyl thiophanate wettable powder with 0.3% seed weight. The seeds can also be soaked in warm soup. First, soak the seeds in cold water for 4 hours, then soak them in 50 ℃ warm water for 5 minutes, then cool them in cold water, dry them and sow them.

3) avoid planting Dutch beans in low wetlands, cultivate them in high beds or ridges, pay attention to ventilation and light, and drain water in time after rain to prevent moisture retention.

4) at the initial stage of the disease, 72% agricultural streptomycin sulfate 4000 times solution or 27% copper noble suspension solution, 30% basic copper sulfate suspension 400 times solution and 47% Ruinong wettable powder solution were sprayed. Stop taking medicine 5 days before harvest.