Study On The Investigation Of Main Weeds And Its Sensitivity To Herbicides In Maize Field Of Heilongjiang Province

Maize is one of the main crops in China, In recent years, the demand for corn as food and industrial raw materials were greatly increased, Corn production and development in a very important position.there is variety of weeds during corn growth,can compete with maize about light,soil nutrient,water and other resources,and severely impair Maize production. With the change of farming system and the development of chemical weeding technology the weed communities in Maize Field were Changed,While the herbicide is used in large-scale and long time,The sensitivity of weeds in maize field will change. The resistance of weeds to herbicides in maize field is more serious.This paper systematic investigate the dominant weed occurrence, distribution and harm of the, in Harbin, Heihe, Mudanjiang, Qiqihar, Suihua, Daqing, Jiamusi in maize fields of Heilongjiang Province. Determined the dominant weed community in Heilongjiang province, Studied on sensitivity of main advantages in different areas of weeds to three commonly used herbicides: atrazine, Nicosulfuron, mesotrione. By the whole plant bioassay to determined the Resistance of dominant weeds to atrazine, Nicosulfuron, mesotrione in different areas of Heilongjiang Province. The results are as follows:(1) Dominant weeds in Heilongjiang province had 11 families and 22 species, The main weeds are widely distributed of Corn field in Heilongjiang Province were, Bamyard grass, Chenopodium album, horsetail. There were some differences in different regions of dominant weeds, Harbin area, Siberian Cocklebur, Cirsium japonicum,Nightshade, thistle of Heihe area, Acalypha australis, Green bristlegrass of Mudanjiang area, The main weeds in Suihua area, were thistle, Asiatic Dayflower, Artemisia scoparia, Qigihar area of Amaranthus retroflexus, Setaria viridis, Artemisia scoparia, The main advantage of weeds in Daqing area for crabgrass, Solanum nigrum, Abutilon, Jia Musi area of were Amaranthus retroflexus, Abutilon, Polygonum.(2) The occurrence regularity of weeds in different regions was rughly the same. Weeds in various regions began to occur in early May,Weed occurrence generally have two peak periods, respectively in late May to early June and in late June to early seven or so, Generally speaking,weed occurrence in the second peak period to reach the most. occurrence of weeds in Mudanjiang, Jia Musi can reach 140 trees per square meters.(3) The main advantage of different areas of weeds in Heilongjiang province to atrazine, Nicosulfuron, mesotrione. barnyardgrass was Reduced sensitivity to to 3 herbicides, Which is most sensitive to atrazine,and sensitive to mesotrione, Nicosulfuron., Horsetail, Commelina communis, decreased sensitivity of copperleaf on 3 herbicides, The lowest sensitivity to Nicosulfuron and to atrazine,mesotrione with moderate sensitivity, Other major dominant weeds Cirsium japonicum, Thistle, Endive,,Solanum nigrum,Green bristlegrass,Amaranthus retroflexus, Crabgrass. in different regions For atrazine, mesotrione, Nicosulfuron were in decreased sensitivity, and all the least sensitive to atrazine.(4) Major maize weed of different area in Heilongjiang Province have different resistance to atrazine Nicosulfuron, mesotrione. Barnyardgrass had a certain resistance to atrazine,the highest resistance was in Harbin,and the resistance coefficient was 3.91.the resistance coefficient in Heihe,Qiqihar,Daqing was respective to 3.41,3.76,3.02, Barnyardgrass on Nicosulfuron had resistance either, the highest resistance was in Harbin,and the resistance coefficient was 4.27. Qigihar’s resistance is also high resistance coefficient is 3.80; Field horsetail on Nicosulfuron has certain resistance, Mudanjiang’s resistance coefficient was highest till to 4.52,there was resistance to atrazine about field horsetail, Both Suihua and Mudanjiang had high resistance, Resistance coefficient was 4.56 and 4.14.