My book is useful for information of different weed species of groundnut, uses of herbicides in groundnut crop and persistence of herbicides through bioassay techniques.Bioassay is generally used as a means of quantitative measurement of biologically active concentration of a herbicide known to be present. However, bioassay sometimes may be used to determine the presence or absence of a particular herbicide. Generally, this task is more difficult because herbicides in the same family may produce similar symptoms. Some qualitative determination is possible Bioassay is a major tool for quantitative and qualitative determination of herbicide residues. In this method, the property of a chemical is measured in terms of some biological responses. Sensitive plant species called as indicator or test species are used for conducting bioassay. The major advantage of this technique is that the procedure followed is generally more economical and easy to perform, costly equipment are not required. The indicator plant is grown in a field or pot and is compared with that of similar plant grown in untreated soil. e.