Question
Hello,

I would like to know if NICOTINE, if extracted in water as tobacco macerate, can become a SYSTEMIC insecticide and be taken up by plants' roots, therefore becoming poisonous for sucking parasites.
I know that nicotinoid chemicals, like IMIDACLOPRID work just like that and are systemic. I also know that in the past, farmers used to prepare tobacco macerates to use as insecticide. But I don't know if that works just by contact with the insects or it is sucked up by plant roots to some degree.

Thank you in advance.

Luca

Answer
Hi Luca,

I am not a biochemist as such, but I will give you what I know.

I am afraid that nicotine will not be taken into the plant easily via the root systems.  The uptake of water and other nutrients into the plant's roots is largely determined by their chemical properties.  Roots are often called lipophiles (which allow lipid molecules to be easily transducted into the root systems. This property allows many herbicides to be introduced into plant tissues.  Though this is not specifically your question, the chemistry still is the same.  Nicotine is a water soluble plant product, nicotine is unlikely to get into the plants roots because of the selective permeability of cell membranes.  The hydrophobic casparian )strip (lipophilic)would force the nicotine solution to travel through the plasma membrane of the plant cells.  Nicotine is less capable (<5% passes through the plasma membrane)of passing through the plasma membrane without a specific transport protein/receptor. Depending on the effective concentration of nicotine in the upper parts of the plants, the use of nicotine may be impractical.  I do know that the nicotinoid operate at the nano and pico molar concentrations.

Hope this has helped.

John