Di-Bak I (Imazapyr) – BioHerbicides Australia

Herbicide is easy to deliver through a hand-held applicator injecting a capsule containing herbicide directly into tree stem or trunk
There is no chemical exposure to the person delivering the herbicide – safe to use
Encapsulated herbicides can be delivered all year round – especially useful to treat trees in down-time
No chemical drift or leakage into the environment

It is a systemic and persistent herbicide with non-selective activity.
In soil, imazapyr is degraded primarily by microbial action.
It is resistant to photolysis or general chemical activity in soil and has a half-life of several months.
It is readily ionised at soil pH greater than 5 and does not readily adsorb to soil particles.
In aqueous environments however it is quickly decomposed in days.
It was granted USA EPA approval for use in aquatic environments in 2003.
It is also considered relatively slow acting presumably due to the necessity of depleting stores of amino acids.
It is not easily degraded within plants so is considered a good contender for killing large woody species.

Imazapyr belongs to the imidazolinone family of herbicides that act by inhibiting acetolactate synthase (ALS) (Herbicide Group B), the first enzyme in the catalysis of the branch-chain amino acids valine, leucine and isoleucine necessary for protein production and cell growth.
After application into the stem, imazapyr is distributed by the plant’s water (xylem) and nutrient transportation (phloem) systems into the leaves and roots.
It can remain active in the plant until the plant dies and microbial activity destroys the herbicide.
However, there is some evidence that some legume species (eg mesquite) may exude the chemical through the roots as a defence mechanism.