Symptoms and control of brown spot of rapeseed

Oatmeal, alias naked oats, also known as bitter lettuce, lettuce, belongs to Compositae, lettuce, is a young shoot, tender leaves as the product of pointed leaf lettuce, leaves are long lanceolate, color light green, texture crisp tender, taste extremely fresh, fragrant, with a unique flavor, containing a lot of vitamin A, vitamin B1, vitamin B2 and a lot of calcium, iron, and other nutrients, is the top grade of raw vegetables, known as "Phoenix tail". Rape belongs to Compositae, which is a pointed leaf lettuce with tender shoots and leaves as its products. the leaves are long lanceolate, its appearance is a bit like the "head" of lettuce, the leaves are slender and spreading, and the bamboo shoots are thin and short. From the perspective of blood relationship, rapeseed belongs to a variety of leaf lettuce-long-leaf lettuce, which is similar to the familiar lettuce, so it is also known as Niu Li lettuce. Its color is light green and its growth is strong. Disease resistance, strong adaptability, crisp and tender texture, taste extremely fresh and tender, fragrant, known as "Phoenix tail".

Introduction of brown spot of rape:

The symptom spot is on both sides of the leaf, the leaf spot is round, nearly round to irregular, wide 1~8mm, light brown to brown, the center is grayish white, the edge is yellow brown, and the color of the back spot is slightly lighter.

The pathogen Cercosporalactucae-sativaeSawada is called Cercospora lettuce, which belongs to semi-known fungi (asexual spores) in the fungal kingdom. Conidiophores and conidia are born on both sides of the leaves, without a sporangium or composed of only a few brown cells. Conidiophores solitary or 1 × 12 fascicled, light brown, unbranched, with 1 × 4 geniculate break points, apically conical, 0 × 4 septum, 25 ~ 115 × 4 ~ 6 (μ m). The spore scar is obviously thickened and 2 ~ 3 μ m wide. Conidia needle-shaped to cylindrical, colorless, erect, apically pointed, base inverted conical, multiple septum, 31 ~ 117.5 × 3 ~ 5 (μ m), in addition to harmful lettuce, but also harmful to mountain bitter, mountain lettuce, long-leaf lettuce, fine-leaf bitter lettuce.

The transmission route and disease condition of the disease overwintered with mycelium and conidia on the remnant of the disease, carried out primary infection and re-infection with conidia, and spread by airflow and Rain Water sputtering. Usually rainy or foggy weather is conducive to the disease, poor plant growth, or partial application of nitrogen fertilizer will aggravate the disease.

Control methods of brown spot of rapeseed:

The main results are as follows: (1) pay attention to the hygiene in the field and combine with picking diseased leaves to collect the diseased remains and take them out of the field to burn.

(2) clear ditch and drainage, apply mature organic fertilizer to avoid partial application of nitrogen fertilizer, timely spray brassine, etc., so as to make the plant grow healthily and enhance its resistance.

(3) at the initial stage of the disease, 78% wave manganese-zinc wettable powder was sprayed 500 times or 2.5% clozonitrile suspension 1200 times, 50% isofloxide wettable powder 1500 times, 86.2% cuprous oxide wettable powder 1000 times, once every 10 to 15 days, continuous prevention and treatment for 3 times.