Symptoms: Curvularia leaf spot disease mainly damages the leaves, and also damages leaf sheaths and temporal lobes. At the beginning, it was a faded green dot and gradually expanded into a round or oval lesion. The lesions are larger on lesions, 1-2 mm wide, 1-4 mm long, and the center is pale, yellow-brown, with a wide rim around the edges, and a wide, translucent grassy yellow halo around the periphery. Several lesions can connect to form a necrotic area. Due to the Curvularia spp. Leaf spot disease in different varieties, especially disease-resistant and susceptible varieties, the lesion size, shape, halo width and other characteristics are very different, and easy to be confused with other leaf spot disease, so The diagnosis should be extra careful and careful. Prevention 1. Selected inbred lines and hybrids with high resistance to resistant varieties: Sutangbai, Yu12, Yu20, Tangkang5, Zhongdan2, Yandan22, Danyu13, 8503, and Langyu6 And so on, can be selected according to local conditions. 2. Cultivate control Firstly, large areas are used to remove field plant disease residues and prevent and reduce the source of initial infection. The corn stalks used by the farmers in northern China to cook rice, which are used up before spring sowing, must also be properly handled. The second is appropriate early broadcast. Early sowing can avoid disease and escape disease, thereby reducing the incidence. The third is to increase fertilization. In addition to the addition of fertilizers and fertilizers, it was necessary to add nitrogen fertilizer. During the inspection, it was observed that where there are thick soil layers, as well as fertilized and top-dressed plots, maize is flourishing, and the incidence is generally lighter. Heavy nitrogen fertilizer can reduce the incidence of disease. More than 30%. 3. Chemical control Through the measurement of the efficacy of 28 pesticides and field trials of some pesticides, 40% Fuxing Milk Oil 5000-10000 times the best control effect, up to 90%. 50% mancozeb WP 500-1000 times, 50% eutectic WP 500-1000 times and 40% methine WP 500-1000 times, followed by 70% the above. However, the price of Fuxing is higher, and the latter three are lower in price and can be used interchangeably. The general disease rate reaches about 10% when spraying control, after the first use of protective agent with the adsorbent, 10-15 days spray 1, even spray 3-4 times, alternate use can ensure the effect, and reduce fertilizer control Cost, but also continue to produce drug resistance, there are many benefits, can be a large area of ​​application. Venlo structure is a popular one at present. This architecture uses horizontal girder as main bearer, forming a stable structure with columns. There is consolidation between horizontal girder and column, and hinge is used to connect column and foundation. Pc Board Venlo Greenhouse,Venlo Greenhouse,Venlo Type Pc Sheet Greenhouse JIANGSU SKYPLAN GREENHOUSE TECHNOLOGY CO.,LTD , https://www.alibabagreenhouse.com
In Venlo greenhouse, foundation is made of reinforced concrete and the side wall is made of brick or reinforced concrete plate. The steel frame always use hot dip galvanized light steel. Roof beam adopts horizontal girder structure and using herringbone connection. The horizontal girder bears 2 or more roofs, which is made of aluminum alloy. This material is used as roof structure material and also glass inlay material. Other beams using gutter style to minimize the section. Delighting material of the roof and side wall using the hollow double-layer or multilayer PC board.
PC board is mainly made of PC/PET/PMMA/PP materials, it need sun screen coating to resist ultraviolet resist and ageing, and it is also required to be anti condensation and antidrug.
As a kind of light material, use PC board can greatly reduce the weight of greenhouse structure, and corresponding reduced the size of the steel frame, which saving the cost of steel.