Influence of Glyphosate on Resprouting of Parent Tubers ofCyperus esculentus

Abstract

Yellow nutsedge (Cyperus esculentusL. # CYPES) was treated with unlabeled and14C-labeled glyphosate [N-(phosphonomethyl)glycine] to study the toxicity and translocation of glyphosate into parent tubers of this weed. When plants of 2 and 4 weeks of age were treated with 0.6 kg ai/ha of glyphosate, fewer parent tubers from treated plants resprouted (14 and 32%) than tubers from control plants (73 and 59%, respectively) of equal age. Also, fewer tubers resprouted from 2-week than from 4-week-old treated plants. The radioactivity of parent tubers from plants treated at 2 weeks of age, which exceeded that of tubers from plants of 4 and 6 weeks of age, indicated that translocation of14C into parent tubers decreased as the treated plants increased in age. The differential amounts of14C translocated appear to explain why applications of glyphosate were more effective in suppressing resprouting of parent tubers from 2-week than 4-week-old plants.