There are so many mechanism and characters govern the selectivity of herbicides including target site action, coupling with organic constituents, morphological character like orientation of leave, types of leaves, rooting depth and their proliferation, waxiness of leaves and stem, corrugation on leaves, hairyness etc. that affect selectivity.

Uma Nath Shukla Thank you for promoting this discussion. Sir you describe many good points. Thanks for your best thoughts... Thanks a lot.

Regards,

I do agree with Uma Nath Shukla.

Rajiv .. Thanks a lot Sir for participate in this discussion and share your valuable experience with us.

Deep Regards

Obvious due to selectivity mechanism...

Like morphology of the plant differs from plant to plant, by this way herbicide molecules may get attach with the broad leaf weeds rather than grassy weeds , say for example 2,4-D ...as this herbicide Kilda broadleaf weeds...other mechanism responsible for selectivity is alteration in the metabolism of the herbicide in the crop plant rather than weed, that by application of herbicide over the crop and weed , kills only weed plant...some of the techniques are conjugation of the herbicide molecules with that of amino acids and other compound, thereby activity of herbicide is reduced...reverse metabolism , beta oxidation , agronomic practices may influence the herbicide selectivity...dose of a particular herbicide will also affect the selectivity as if we we increase the dose of herbicide, they will become lethal to crop species also...

Thanks for your valuable statement regarding herbicides.... its help me to gain more knowledge about herbicide.

Thanks a lot Himanshu Verma