利用水葫芦象甲和农达综合控制水葫芦

试验表明同时应用水葫芦象甲和农达控制水葫芦，可达到快速、持续的控制效果，但农达使用剂量应选择适当。药量４.５ｋｇ／ｈｍ^２的综防处理区中，由于农达的作用水葫芦植株在２０～５０ｄ内大部分死亡，水葫芦象甲亦很快死亡，象甲很难发挥有效的作用；药量为０.４５ｋｇ／ｈｍ^２的综防区中，水葫芦象甲和农达同时作用，对水葫芦的叶片数、繁殖量和生物量起到了明显的抑制作用，与单独施用同样药量的化防区和只释放象甲的生防区有显著差异，而且象甲保持了一定的种群密度；而药量为０.０４５ｋｇ／ｈｍ^２的综防区与只放象甲的生防区控制水葫芦的效果一样。

Integrated control of Eichhornia crassipes using Neochetina eichhorniae Warner and herbicide Roundup

In order to reach a fast and sustainable suppression of water hyacinth, Eichhornia crassipes, control effect tests with the weevil, Neochetina eichhorniae, after sprayed with 41% Roundup (glyphosate) at different concentrations were conducted in plots outdoor. The results showed that 50%-100% plants died after 3-8 weeks of spraying Roundup at the concentrations of 4 5 kg/hm 2 and 1 5 kg/hm 2, and all the weevils also died because of the lack of food. Contrastingly,in the plots treated with Roundup at the concentration of 0 45 kg/hm 2 the weevil remained its population well. Reproduction and biomass of the plant were greatly suppressed under the joint effect of the weevil and herbicide. There was no great difference in control effect between the plots treated only with weevil and the plots treated both with the weevil and Roundup at the concentration of 0 045 kg/hm 2. It indicated that the herbicide at this concentration could not suppress the growth of the plant. The paper reveals that it is possible to use the weevil and Roundup to control water hyacinth at same time,but the concentration should be controlled on suitable level, so as to leave enough food for weevil.