两种除草剂对水葫芦和大薸的防除效果

采用枯叶指数、枯柄指数、新根抑制、鲜重防效等指标,评价480g/L灭草松水剂和10%硝磺草酮可分散油悬浮剂对水葫芦及大薸的防除效果。盆栽毒力测定结果表明,10%硝磺草酮可分散油悬浮剂对水葫芦和大薸新根有很好的抑制作用,药后10d,LC50分别为14.22和7.21mg/L;480g/L灭草松水剂对水葫芦和大薸鲜重的毒力较强,药后10d,LC50分别为548.22和3.49mg/L;药后20d,LC50分别为53.28和3.31mg/L;而2种除草剂对水葫芦叶片、叶柄和大薸的叶片毒力均较低,其中480g/L灭草松水剂对水葫芦叶片和叶柄毒力优于10%硝磺草酮可分散油悬浮剂,药后30dLC50分别为94.40和93.43mg/L;对大薸叶片毒力较强的是10%硝磺草酮可分散油悬浮剂,药后20dLC50为165.07 mg/L,在实际应用中,为提高防治效果,可适当提高剂量或进行混配处理。

Control effect of two herbicides on water hyacinth and water lettuce

The control effect of water hyacinth and water lettuce by 10% mesotrione dispersed oil suspensions and 480 g/L bentazone aqueous solution were evaluated by withering leaf index, withering petiole index, and the inhibition to new roots and fresh weight. The result showed that mesotrione 10% OD showed high toxicity to both water hyacinth root and water lettuce root, with the LC50 values of 14.22 mg/L and 7.21 mg/L after 10 d treatment, respectively. Bentazone 480 g/L AS has relative high toxicity to fresh weight of water hyacinth and water lettuce, with the LC50 values of 548.22 and 3.49 mg/L after 10 d treatment and 53.28 and 3.31 mg/L after 20 d treatment, respectively. However, the toxicity of the two herbicides was relatively low to leaf and petiole. Bentazone 480 g/L AS had a higher toxicity to leaf and petiole of water hyacinth than mesotrione 10% OD, with the LC50 values of 94.40 and 93.43 mg/L, respectively, while mesotrione 10% OD had a higher toxicity to leaf of water lettuce, with the LC50 value of 165.07 mg/L. In practical application, in order to improve the control effect, the dosage can be appropriately increased or mixed with each other.