Control Effects Of 2,4-D Dimethylamine Salt On Alternanthera Philoxeroides And Safety Evaluation Of 2,4-D On Environmental Organisms

Alligator weed, Alternanthera philoxeroides (Mart.) Griseb is a serious exotic weed, and is now controlled mainly by chemicals.2,4-D dimethylamine salt (2,4-D) is a kind of selective and systemic hormonal herbicide and has a good control effect on alligator weed. Until now, there are few researches on the safety of 2,4-D to environmental organisms. This paper will explore the toxicity of 2,4-D to 9 environmental organisms to offer scientific reference for the use of 2,4-D.The control effect to A. philoxeroides was also studied in this paper. The experimental results showed that the control effects of 2,4-D to A. philoxeroides 7 days after spraying was positively correlated with the concentration of 2,4-D with the equation of y=7.649x+58.285 (R2=0.943). The SPAD values of A. philoxeroides 7 days after spraying were negatively correlated with the concentration of 2,4-D with the equation of;y=-63.828x+37.197 (R2=0.817).The toxicity of 2,4-D to 9 non-target environmental organisms was determined in the laboratory.2,4-D had a low toxicity toward Apis mellifera with the LC50-48 h of 841.85 mg·L-1 by oral feeding and with LC50-48 h> 100 μg·ndividual-1 by contacting; a low toxicity to Coturnix japonica with the LD50-48 h of 529.60 mg·kg-1 by oral feeding; a low acute toxicity to Danio rerio with the LC50-96 h>100 mg·L-1, to Scenedesmus obliquus with the EC50-72 h>100 mg·L-1, to Daphnia magna with the EC50-48 h> 100 mg·L-1, to Xenopus laevis with the LC50-48 h> 100 mg·L-1, and to Bombyx mori with the LC50-96 h>2000 mg·L-1; a low toxicity to Trichogramma ostriniae with the safety coefficient>5; and a low toxicity to Eisenia foetida with the LC50-14 d > 100 mg·kg-1. Therefore,2,4-D had a low toxicity to environmental organisms.