Using Pachyrhizus erosus (jícama) as a pesticide.

[tripsis]

I'm interested in growing some Pachyrhizus erosus for the yams it produces, but the entirety of the above ground portion of the plant contains rotenone, which is used commercially as a pesticide. This is also of interest for me, as I like the idea of being able to produce my own pesticide for when the need arises.

With that said, I'm not sure how I would go about using it as a pesticide. Could I simply crush the leaves, etc., in water and use as a spray? Or would I need some solvent like alcohol? Would it be strong enough as is, or is an extraction necessary?

Any help is much appreciated.

[applesnail]

I think you would just use water, solvent could be harmful, but I have made a homemade pesticide with moonshine, tobacco, onion and garlic,trying to kill spider mites(didnt work tho) the alcohol evaporates quite quickly off plant tissue supposedly, although I sprayed my cacti with it panicked about the pure alcohol and sprayed em with water, if you soaked the crushed leaves and strained, then just try and find the effective concentration perhaps by boiling it down, this is interesting, im interested in this also, ive started growing pyretheum for the exact same purpose to make my own insecticide, id grow a neem tree to if i could! Perhaps someone with some chemistry experience in pesticides or insecticide manufacture etc may elaborate?

[poisonshroom]

Alcohol should be fine for cacti (iv wiped a bigish PC pach down with metho to try and kill what look like baby scale or mealies) not sure about other plants though. Id say try water first, but if you use alcohol you can always make a tar that you can dissolve in water (at varying concentrations to test), and that should keep for a while too if you store it right.

EDIT: even if the alcohol tar doesnt dissolve in the water, by shaking it you could make a suspension (like with liquid ferts that settle during storage)

Edited March 25, 2011 by poisonshroom

[Torsten]

I did not know about the rotenone. thanks!!!

[planthelper]

ok, let's 1st find out the solubilety of rotenone...

wiki say's soluble in ether, aceton and slightly in ethanol.

maybe, ther is some solubilety in water, but i remeber a recepie for making a pest spray out of neem seeds, and it stated that, first extracting the seeds in alcohol and than mixing with water made a much better spray than water alone.

i would, dry the plant material, put it in a sealable jar, add aceton (maybe metho works aswell), shake once in a while, leave for a week, and than strain the plant matter out of the solvent.

edit:

i just realised, if it's used as a fish poison, than it has to be soluble in water at least to a degree.

aswell it say's that rotenone get's destroyed bu sunlight fast, so one has to dry the material rather in the dark, and store it dark.

Edited March 25, 2011 by planthelper

[tripsis]

Thanks PH, I should have looked up rotenone on Wiki like you did. Would have answered at least whether it was soluble in water or not. I'll definitely give this a go when I have some plants growing.