A primary metabolite is a kind of metabolite that is directly involved in normal growth, development, and reproduction. ... Conversely, a secondary metabolite is not directly involved in those processes, but usually has an important ecological function (i.e. a relational function)Primary metabolites prominently functions growth, development and reproduction of cell. Primary metabolites perform their function as molecules signaling to trigger defense response. We have highlight the new trends in utilizing primary metabolites for controlling bacterial, viral and FUNGAL pathogens and insects.Some common examples of primary metabolites include: ethanol, LACTIC acid, and certain amino acids. In higher plants such compounds are often concentrated in seeds and vegetative storage organs and are needed for physiological development because of their role in basic cell metabolism.Secondary metabolites are compounds that are not required for the growth or reproduction of an organism but are produced to confer a selective advantage to the organism. For example, they MAY inhibit the growth of organisms with which they compete and, as such, they often inhibit biologically important processes.Secondary metabolites serve: (i) as competitive weapons used against other bacteria, fungi, amoebae, plants, insects, and large ANIMALS; (ii) as metal transporting agents; (III) as agents of symbiosis between microbes and plants, nematodes, insects, and higher animals.Examples of secondary metabolites include antibiotics, pigments and scents. The opposite of secondary metabolites are primary metabolites, which are considered to be essential to the normal growth or development of an organism.