At present, the number of alien invasive species confirmed by the state has reached 544, more than 100 of which have spread on a large scale and caused severe harm. Due to their numerous invasion channels, high rate of reproduction, and harmfulness, invasive species are threatening biodiversity and causing huge economic losses in China. The advanced transportation network and suitable environmental conditions in Henan Province have provided conditions for the invasion and survival of harmful species. Tian et al. (2005) reported the presence of 30 alien invasive plants in Henan Province; on December 28, 2005, Henan Daily announced 12 alien invasive plants; Zhang (2006) reported 26 alien invasive plants in the agricultural regions of eastern Henan Province. Likewise, Liu Ying et al. (2008) discovered 34 alien invasive plants (including 1 aquatic plant and 33 terrestrial plants), and Zhu et al., (2007) and Dong et al., (2007) respectively reported 53 alien invasive plants found in Henan Province. However, Dong et al., 2007 mistakenly included Eleusine indica, Nasturtium officinale, Ludwigia prostrata, Cuscuta japonica, Prunella vulgaris, and other plants in the list of alien invasive plants. Jiang et al., (2009) declared the number of alien invasive plants in the suburbs of Xuchang to be 46; Zhang et al., (2010) described nine newly-confirmed alien invasive plants. In 2011, Xu and Jian (2011) listed 62 alien invasive plants found in Xinxiang; Wang and Gao (2012) discovered four alien invasive plants in their investigation on highways in Henan Province. The coverage of alien invasive species by previous studies used ambiguous concepts and failed to provide either voucher specimens or photographs, making it difficult for successors to confirm their results. In addition, these studies only recorded the species of invasive plants in Henan Province, but did not perform any dynamic monitoring on the main invasive plants for agricultural lands in Henan Province.
Thus, for the purposes of investigating and monitoring invasive plants in Henan Province, it is valuable to conduct a province-wide investigation on the regions of distribution, area of spread, invasion route, and law of spreading of the main alien invasive plants for agriculture, creating an information database, distribution map, and propose targeted control schemes and measures.