Barley net spot

Symptoms mainly affect the leaves and leaf sheaths and less infect the stems. The incidence of seedlings, lesions more than 1-2cm away from the tip. The incidence of adult plants mostly starts from the base leaves, and the tips of the leaves turn yellow. The brown spots on the health boundary are unclear. There are reticular mesh lines in the vertical and horizontal direction. When there are more lesions, they become stripe-like spots and produce a small amount of spores. The glume of the victim produces an unwoven brown spot.

The pathogen Drechslera teres (Sacc.) Shoem.=Helmnthosporium trers Sacc. said barley net spot Helminthosporium spp. The sexual state is Pyrenophora trers (Died.) Dreechs. The circular pyocyanidium is an Ascomycete subphylum fungus. Conidia pale olive, cylindrical, with 1-10 diaphragm, size 30-17515-22.5 (μm). Conidia stems more than solitary, but also 2-3 bundled, straight, only the top microbend. The ascostic shell forms on the sick body. Ascosi shells are dark brown and nearly elliptic in size, 430-800300-600 (μm) in size. The ascospores are colorless, stick-shaped, containing 8 ascospores and sometimes 4. Ascospores are brownish-brown, nearly elliptic, 40-62.517.5-27.5 (μm) in size.

Transmission Pathways and Pathogenic Conditions Mycelium latent in seed coats and spores attached to seed surfaces are the main primary infestation sources, and ascospores on diseased bodies can also infect. Seed borne pathogens cause seedling disease. The diseased part produces spores that re-infect through the wind and rain, and the flower part damages the seeds. When it matures, it forms ascospore shells on diseased bodies such as wheat hulls. The bacteria can survive for 7 years. Spore germination temperature of 20-25 °C. 20 °C, relative humidity 100% incidence of rapid. Low temperature, low light, and high humidity are favorable for diseases. The incidence of winter barley sowing was heavier.

Control methods (1) Selection of disease-resistant varieties such as early maturing No. 7, Liang Erling, Zhe Nong 8 et al. 92) Early sowing should be done in a timely manner so as to avoid continuous cropping. (3) Chemical control: (1) Promote the use of soaking spirit (TH88) 2ml, 20kg of water, mix and soak 10kg of barley seeds, soak after 24 hours. Soaking seed easy photolysis, soaking in the indoor or take light measures. Other seed treatments can be found in barley striasis. 2 Spray 50% carbendazim WP 800 times or 60% anti-mildew WP 100-1500 times and 70% MnZn WP 500 times in the early stage of disease.