Prevention and control of winter vegetable seedling diseases
Winter vegetable seedling diseases mainly include rickets, blight and roots. Timely pesticide control is necessary.
Disease identification points: Before the seedlings were unearthed, the roots of the stems were invaded by thin bacteria and collapsed on the ground. When the seedbed is humid, the white flocculent hyphae are often densely formed on the bed of the diseased seedling or its vicinity, which is different from the blight.
After the infestation of the stems of the seedlings, the stems of the seedlings became brown and contracted, and the stems and leaves were dying; the slightly larger seedlings were wilting during the day, recovered at night, and did not collapse after the death. The diseased part has a concentric pattern and a pale brown spider silk mold, which is an important feature of the disease that is different from the disease.
The roots are mainly due to the ground temperature below 12 ° C, and the duration is longer, coupled with excessive watering or rainy weather, the vegetable seedlings appear wilting, and the roots will occur for a long time. It is characterized by no new roots or adventitious roots in the roots. The root bark is rusted and rotted, easy to pull up, and the upper part of the leaves is scorched. In severe cases, it is dry and dry.
Second, prevention and control methods Agricultural control (1) water management: seedlings should try to control watering, especially in the evening watering is easy to lead to high humidity, watering must be selected to spray on sunny days, not suitable for flooding.
(2) Temperature and humidity control: When the temperature is low, cover the film. When the temperature is lower than 0 °C, cover the straw curtain and pay attention to the early cover. The seedbed should be ventilated and dehumidified in time, even if it is cloudy, it should be properly ventilated and drained.
According to the China Pesticide Network , the prevention and treatment of cockroaches can be treated with DuPont Easy Water Dispersible Granules 800-1000 times, 70% Dixon Powder 1000 times, 50% Carbendazim Powder 500 times, 58% Metalaxyl Manganese Zinc powder 500 times or 72.2% Plex water agent 600 times liquid spray; blight control can be used 70% diclofenac powder 1000 times, 70% methyl thiophanate powder 1000 times or 5% Jinggangmycin water 1500 times Spraying; when mixed with two diseases, it can be sprayed with 50% Fumex WP 800 times and 72.2% Plex water 600 times. The above agents are separated every 7-10 days, depending on the condition, and prevent 2-3 times.
Stainless Steel Welded Square Pipe
Stainless steel square tube is a hollow strip of steel, because the cross section is square so called square tube. A large number of used for conveying fluid pipelines, such as oil, natural gas, water, gas, steam, etc., in addition, in bending, torsion strength at the same time, lighter weight, so it is also widely used in manufacturing machinery parts and engineering structures.
Stainless steel square tube classification: square tube is divided into seamless steel tube and welded steel tube (seam pipe) two categories. According to section shape can be divided into square and rectangular tube, widely used is circular steel tube, but there are some semicircular, hexagonal, equilateral triangle, octagonal and other special-shaped steel tube.For stainless steel square tube under fluid pressure to carry out hydraulic test to test its pressure capacity and quality, under the specified pressure does not leak, wet or expansion for qualified, some steel pipe according to the standard or the requirements of the side of the roll test, flaring test, flattening test.
Square tube specifications :5*5~150*150 mm thickness :0.4~ 6.0mmSquare tube material :304, 304L, TP304, TP316L, 316, 316L, 316Ti, 321, 347H, 310S, etc.The production process is: a. Round steel preparation; B. heating; C. Hot rolling perforation; D. cutting head; E. pickling. F. grinding; G. lubrication; H. Cold rolling; I. degreasing; J. Solution heat treatment; K. straightening; L. in cutting; M. pickling. N. Finished product inspection.
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