Of course, biologicalcontrol agents can safely be released only if it can be verified that they feed solely on the target weed.
当然，只有能够证明它们仅以目标杂草为食，生物控制剂才能安全释放。
2
In the biologicalcontrol of weeds, the measure which was first studied and applied, and which has also been proved effective is weed-control by insects.
在杂草的生物防除中，研究和应用得最早且证明效果最好的措施是利用昆虫防除杂草。
3
In order to protect the public water system from chemical herbicides pollution, biological method has been suggested to control the growth and the reproduction of this weed.