Survey on Alien Invasive Weeds in Farmlands in Hubei Province

Alien invasive weeds in farmlands in Hubei province were surveyed with seven grades by visualization of weed dominance to crop in 2007.The results showed that there were 23 alien invasive weed species in 101 sample sites of wheat,oilseed rape,rice paddy and cotton fields in Hubei Province,belonging to Asteraceae(8 species),Poaceae(2 species),Amaranthaceae(2 species),Euphorbiaceae(2 species),Solanaceae(1 species),Phytolaccaceae(1 species),Leguminosae(1 species),Umbelliferae(1 species),Brassicaceae(1 species),Geraniaceae(1 species),Malvaceae(1 species),Plantaginaceae(1 species) and Scrophulariaceae(1 species).In wheat fields,there were 11 alien invasive weed species,accounting for 23.40% of the total weed species,among which,Avena fatua,Veronica persica,Brassica juncea var.gracilis and Geranium carolinianum were the most serious weeds.In oilseed rape fields,there were 15 alien invasive weed species,accounting for 14.02% of the total weed species,in which,A.fatua and V.persica ranked top 2 of 11 swart weeds.In paddy fields,the only invasive weed Alternanthera philoxeroides has become the main weed with its occurrence frequency of 61.60%.In cotton fields,there were 15 alien invasive weed species,accounting for 17.24% of the total weed species,in which,Amaranthus retroflexus,Eleusine indica and Euphorbia maculate were the most serious weeds.This research had great significance in clanifying the alien invasive weed species,their occurrence frequency and harm to crops in farmlands in Hubei province;it had also provided basic data for future survey.