Abstract:Ipomoea cairica is a notorious weed which has serious harm to the environment in South China. The effects of three chemical herbicides, such as 2,4-D butylate, dicamba and fluroxypyr, on control of I. cairica in the field were studied. The results showed that 2,4-D butylate (1.00 mL L-1) could eradicate this weed. The death rate of I. cairica stems and leaves was close to 100% after spraying 2,4-D butylate (1.00 mL L-1) in 20 days. The total biomass also decreased significantly in 60 days (P<0.05), and the growth did not recovery after 90 days. The final control effect of 2,4-D butylate (1.00 mL L-1) on Ipomoea cairica was 99.8%. After spraying dicamba (1.00 mL L-1) and fluroxypyr (1.00 mL L-1) in 40 days, the death rate of I. cairica stems and leaves were 99.0% and 100%, respectively, and the regeneration rate of I. cairica was 10% and 100% after 90 days. A few roots were survival sprayed dicamba (1.00 mL L-1) after 40 days. The herbicide residue analysis showed that 2,4-D butylate could degrade quickly with half-life for 14 days, and it could not be detected in the soil after 80 days. Furthermore, 2,4-D butylate (1.00 mL L-1) was relatively safe to other plants, which could regenerate after spraying 2,4-D butylate in 1 year. Therefore, it suggested that the Ipomoea cairica growth could be good control treated with 1.00 mL L-1 2,4-D butylate.