Study on the occurrence and control of weeds in Allium schoenoprasum field

The investigation was carried out on the weeds' occurrence and damage and the ways of controlling the weeds by herbicides,and the analysis of pesticide residue in A.schoenoprasum was also made.The results showed that there were 62 species of weeds under 23 families in A.schoenoprasum field.The weeds mainly came under Gramineae and Compositae,and both families' weed species were respectively 21.0% and 19.4% of total weed species.Among all the weeds the annual,biennial and perennial weeds were respectively 63.5%,29.7% and 6.8%.The 5 herbicides had a good control efficacy on the weeds of A.schoenoprasum field.The control efficacy of 96% s-metolachlor EC at 1 008.0 g a.i./hm2 on gramineous and broad-leaved weeds was respectively 96.6% and 95.8%,and the control efficacy of 50% isoproturon WP at 1 125.0 g a.i./hm2 on them was respectively 95.7% and 94.8%.The pesticide residue in A.schoenoprasum was within the standards for export agricultural products.But the 2 herbicides 24% oxyfluorfen EC and 20% fluroxypyr EC should not be applied because when they were applied respectively at 270.0 g a.i./hm2 and 180.0 g a.i./hm2,the pesticide residue in A.schoenoprasum would go beyond the Japanese and EU standards of pesticide residue in vegetables.