Parsnip foliage as an insecticide?

[Durgan]

http://www.durgan.org/URL/?WPFWM 8 July 2012 Parsnip.No Insect Foliar Damage
Observing plants in the garden, it was determined that parsnip vegetation never has any insect damage. Exposure is to the Colorado Potato Beetle, Flea Beetle, Japanese Beetle, Cucumber beetle, Squash Vine Borer.These insects are present in various numbers in the garden area.The defences are limited since Integrated Pest Management (a euphemism for what ever it takes) is practised. The armoury consists of Diatomaceous Earth (Efficacy doubtful) Spinosad, Bacillus thuringiensis (Bt), and of course hand destruction.The issue is the possibility of determining the active protective ingredient in parsnip foliage, and using this poduct in powder or liquid form to protect other plants.All a typical home gardener can do is grind the foliage, liquify and strain and use as a spray.Maybe this observation should be taken up at some university as a research project.

[Ellendra]

Umm, one very important warning might be prudent here: parsnip foliage contains chemicals which, when in contact with skin, react in sunlight to cause a fun little condition called "phyto-photo-dermatitis". The reaction is such that it can be mistaken for either a severe case of poison oak, or a chemical burn. The scars last for years. It has also been known to cause permanant blindness. Please be careful!!

One of my neighbors ended up with parsnip "burns" over 90% of her body after deciding to dispose of the foliage in their burn pit. The smoke carried the chemical.

[MKG]

It's no coincidence that the wild parsnip is also known as Blisterweed.

On the other hand, I have no idea about domesticated parsnips - although the "internet knowledge" is that the foliage can cause severe irritation.

The question would be, I suppose, that if Durgan's observation is to be tested then it would be a good idea to find out first whether the irritants would be destroyed by the treatment to turn the foliage into an insect deterrant or, indeed, if it is those very irritants which provide the anti-insect effect.

Mike

[grahamhobbs]

Interesting line of inquiry. Although there are a number of veg that are relatively pest free, but does that make them insecticidal? incidentally parsnips in this country suffer from leaf miners.

[Odsox]

I have no idea about domesticated parsnips - although the "internet knowledge" is that the foliage can cause severe irritation.

While I do not dispute this in any way, I have a couple of observations to make.
I've been growing parsnips for umpteen years and I must have touched the foliage on innumerable occasions but I don't remember getting any skin reaction (I don't grow them now so can't test the theory). Also I would have though that seed companies would have a very prominent warning on their seed packets to avoid litigation.
It seems odd.

[boboff]

I have lots of hog weed, and thats the same, with regard to blistering in the sun. When I forget and strim in a T shirt, I end up with lots of blisters on my forearms and face, the scars can last up to six months, and the make me look like a serious drug user!

The thing I don't understand either, and related to this is that Rhubarb and Potato plants are poisonous, or so I thought, but the Slugs here strip the leaves clean!

[grahamhobbs]

Now rhubarb tea is used as an insecticide against white fly.

[sleepyowl]

Onion or garlic tea can bee used against greenfly

[diggernotdreamer]

My rabbits and poutlry avoid parsnip foliage like the plague but eat most othery greenery quite happily, nothing seems to eat ground elder either