人類的商業行為中，以農產品進出口的貿易行為傳播雜草的機率最大，藥試所於2002-2010 執行「進口植物有害生物偵測鑑定」計畫，由防檢台中分局、高雄分局等單位從進口的大宗農產品中採樣，共檢測了924 件樣品，分別來自16 個不同的國家，85.6%的來源是美國。進口的農產品包含了29 種作物，其中以黃豆、玉米為大宗，進口農產品中雜草夾雜率平均為87.7%。檢出的雜草種子共計22 科130種，以禾本科33 種最多，其次是菊科20 種、豆科14 種、蓼科9 種、旋花科8 種、藜科與莧科各7 種、錦葵科6 種、十字花科5 種，以上八科的種類已超過所有檢出雜草的84%。檢出的130 種雜草中有40 種是台灣未記錄的，其中Euphorbia esula (乳漿大戟)，為全球百種入侵物種之一，原產於歐洲與溫帶亞洲，已經在世界各處被發現。Amaranthus hybrids (莧科/綠穗莧)、Amaranthus retroflexus（莧科/反枝莧）、Ambrosia trifida (菊科/三裂葉猪草)、Brassica nigra (十字花科/黑芥)、Bromussecalinus (禾本科/黑雀麥)、Bromus tectorum (禾本科/旱雀麥)、Convolvulus arvensis(旋花科/田旋花)、Emex spinosa (蓼科/刺酸模)、Phalaris minor (禾本科/小加拿麗鷸草)、Sida spinosa (刺黃花稔/錦葵科)、Tagetes minuta (菊科/墨西哥萬壽菊)與Thlaspiarvense (十字花科/菥蓂) 等是在中華民國輸入植物或植物產品規定中被歸類為檢疫有害雜草。

Weed seeds mixed with imported agricultural products have been found by theBCIQ quarantine office. Total of 924 samples were examined for weed seedcontamination, and 88% of samples contaminated by weed seeds. More than 130 weedspecies of 22 families existed in imported agricultural products. Major plant taxa of theseweeds are Gramineae, Compositae, Leguminosae, Polygonaceae, Convolvulaceae,Chenopodiaceae, Amaranthaceae, and Cruciferae, contributing to 84% of the weed florain tested samples. Our survey of weed seed specimens shows some plants newlydiscovered in Taiwan, such as Amaranthus hybrids, A.retroflexus, Ambrosia psilosachya,A. trifida, Brassica nigra, Bromus secalinus, B. tectorum, Convolvulus arvensis,Euphorbia esula, Phalaris minor, Sida spinosa, Tagetes minuta, and Thlaspi arvense..