4种除草剂及其混剂对苜蓿田播娘蒿的防除效果

通过田间试验,比较咪唑乙烟酸、苯达松、唑嘧磺草胺、草除灵4种除草剂及其混剂对苜蓿田播娘蒿的防效、对苜蓿的安全性及增产效果,为华北地区苜蓿田杂草的防治提供依据。结果表明,5%咪唑乙烟酸AS及其混配处理对播娘蒿表现出较好的生长抑制作用,其中5%咪唑乙烟酸AS 1 800、2 250 m L/hm~2处理及5%咪唑乙烟酸AS 1 800 m L/hm~2分别与48%苯达松AS 1 500 m L/hm~2、30%草除灵EC 450 m L/hm~2、80%唑嘧磺草胺WG 56.25 g/hm~2混用处理对播娘蒿防效较好,鲜质量抑制率分别为76.05%、84.23%、77.65%、79.45%、85.81%;但5%咪唑乙烟酸AS 1 800 m L/hm~2与80%唑嘧磺草胺WG 56.25 g/hm~2、30%草除灵EC 450 m L/hm~2混用处理对苜蓿有明显的药害,苜蓿株高抑制率分别为33.33%、39.61%。30%草除灵EC 450 m L/hm~2和80%唑嘧磺草胺WG 56.25 g/hm~2对播娘蒿防效较差,鲜质量抑制率低于32.63%。5%咪唑乙烟酸AS安全性好、防效高,可进一步示范推广使用。

Control Effects of Four Herbicides and Their Mixtures on Descurainia sophia in Alfalfa Field

The control efficacy of formulated 5% imazethapyr AS,30% benazolin EC,80% flumetsulam WG,48% bentazon AS and their mixtures on Descurainia sophia and their selectivity to Medicago sativa were studied under field conditions,to provide a basis for controlling weeds in alfalfa field in North China. The results indicated that 5% imazethapyr AS and related mixtures showed good inhibition on Descurainia sophia. 5% imazethapyr AS (1800,2250 mL/ha),5% imazethapyr AS (1800 mL/ha) plus 48% ben-tazon AS (1500 mL/ha),30% benazolin EC (450 mL/ha),or 80% flumetsulam WG (56. 25 g/ha) had higher control efficacy,which controlled 76. 05%,84. 23%,77. 65%,79. 45%,85. 81% Descurainia sophia respectively,based on fresh weight determination. 5% imazethapyr AS (1800 mL/ha) plus 80%flumetsulam WG (56. 25 g/ha) or 30% benazolin EC (450 mL/ha) had obvious inhibitory effect on Medicago sativa,with the inhibition rate of 33. 33% and 39. 61% based on plant height determination. 30% benazolin EC 450 mL/ha and 80% flumetsulam WG 56. 25 g/ha both did not provide adequate control of Descurainia sophia,with fresh weight inhibition rate less than 32. 63%. Because of the higher control efficacy and good selectivity provided by 5% imazethapyr AS,it can be recommended in the field.