There are a very large number of plants which contain compounds lethal to terrestrial as well as aquatic pests at doses which are some times below those for synthetic pesticides. Use of such products has the additional advantage that these likely to cause contamination of the environment. After all, such compounds are not confined to the plants in which they are found but also possibly get distributed in the environment through air and water. Most of the studies have been done in this area however suffer from one common drawback. While there is much information on the toxicity and lethal...