Research progress and prospect about exotic invasive species Phalaris minor Retz.

Phalaris minor Retz., a native weed of the Mediterranean region, is the most serious annual grass weed in winter wheat fields. This paper reviewed the current state of researches on the invasive species, P. minor. Globally, P. minor has been reported in over 60 countries, covering all the continents except the polar regions. Presently, P. minor has spread widely across Yunnan Province and can now be found in Kunming, Chuxiong, Yuxi, Dali, Baoshan, Dehong, Yuxi and Honghe Cities. It is considered a seriously threat to the local economy and food production. The international drive is to adopt more effective and scientific forecast and control for P. minor infestation. In recent years, an increasing number of foreign researchers have become interested in studying this weed species and thus much progress has been made in understanding the biology and ecology of this species of weeds. However, research on P. minor in China has remained largely inadequate, resulting in difficulties in developing reliable early warning and control system for the weed. This paper reviewed some of the hot research issues on P. minor based on the abroad and domestic research results, including its distribution all across the world, the possible reasons for the damage it caused to crops (e. g. interspecific competition, allelopathy), the mechanisms underlying its invasion and spread, genetic variations in the weed population, and the highly adaptive ability and biological characteristics of the invasive weed to explain its highly successful rate of spread (e. g., morphological similarity of P. minor with wheat, small seed size and persistent soil seed bank). The paper also reviewed control methods of P. minor, which were divided into three general categories — manual, chemical and biological. Finally, three areas of future research were proposed: 1) multi-disciplinary mechanisms underlying its invasion and spread; 2) eco-physiological adaptation of the invasive species to global climate change; and 3) effective control of the invasive species. Thus it was very important to build an in-depth research on the invasive species in order to predict and prevent the successful invasion of P. minor, and to eventually lay the theoretical and technical support for the management of P. minor.