I was reading one of my vegetable gardening books last night and came across this snippet that may be of use to people.

Rhubarb leaves contain oxalic acid and are poisonous if eaten - now I knew this, but didn't know that if you shred them and boil them in 500ml - 1 litre of water for half an hour the resulting solution can be strained and used as a spray against spider mite and aphids.

ATB

Anyone tried this yet? My strawberries are crawling in greenfly and smaller pinkish aphid things...

And my new GR is a bit near the garden....

Did you know { prat alert!} it's technically illegal to make your own pesticides?
But hey, break one gardening law, you might as well break some more while youre doing it!
Come to think of it, I'm not entirely sure if that's still true. anyone confirm the legal status of homemade sprays?
Hope it works well though,
regards, Jim the prat

Edit to add:
""Regulations made under the Food and Environment Protection Act 1985 give legal force to those parts of the manufacturer’s instructions that are indicated as being “statutory conditions of use”. This means that it is illegal to use the wrong dilution rate or to use a product for purposes other than those stated in the instructions. A prosecution could follow if careless spraying of plants in flower results in a beekeeper losing his bees. Only products approved by the government can be used as pesticides, so home-made pesticides brewed from concoctions of rhubarb, cigarette butts or even washing-up liquid are now outside the law""

from the RHS.org website.

I had'nt heard either of those things...the rhubarb leaf for pests or that it was illegal to male your own pesticides.

Ah well.....I'm picking rhubarb later and I've greenfly on the roses,so I'll give it a go

Let us know how it goes mate. I need to source some rhubarb leaves (off my mam), so I've gone the garlic spray route for now.
Bit worrying that it could be toxic to bees mind. (the rhubarb leaf i mean)

I'm in a bit of a quandary now....IF its detrimental to bees..No way will I use it but I can't find anything on Google to say it is!!

Although some reading suggests its best not to use it on fruit and veg!? especially if you have heart problems.

I have ...........so unless someone can give me a decent link to research that refutes it.....I'll give this one a miss .

A shame really because I do like to use stuff thats come from the garden back in the garden.

Oops!Sorry. Sparking a panic whilst being a twat.

I assume the bees thing is a hypothetical situation arising should a commercial farmer blanket spray his fields with a 1.25x strength pesticide, then his 5 mile downwind neighbour's apiaries all suffer, he's liable for prosecution.
If you're using rhubarb leaf spray sensibly (ie. by hand, not cropsprayer) no bees will come to harm.
Sorry again,
Jim the prat!

edit; spray at night or really early to avoid beneficial insect harm!

I was watching a bee keeping program the other day and one of the growers fed them some oxalic acid in syrup, to kill the varroa mites on the bees. It is toxic to the bees but much less so than for the varroa mites, so the dosage can be kept at a level safe for the bees yet harmful to the varroa mites. What level would be toxic to spider mites is another matter though.

http://www.dave-cushman.net/bee/wallyshaw.html
http://www.apiservices.com/articles/us/spr...oxalic_acid.htm

Good info there Gunnaknow....

I think I'll still try this this summer if my aphids get too bad.... Spraying at night sounds a good bet to help out the bees.
See if it works on the strawberries.. might keep it in mind for Canna... Spidermites scare me

I presume this sort of spray can be used up until late veg/ early flower? surely that'll give the oxalic acid time to break down?
Unless its systemic?

BTW garlic and tobasco spray seemed to shift the pink aphids, although the green winged ones weren't gone for long..

Been down the lottie tonight and for the first time in my experience.... I've got blackfly on my runner beans and being as I was picking Rhubarb and other stuff for dinner tomorrow...I thought about this thread and.........

Its bubbling away...


Click to view attachment.


I'll let you know how I get on.

Nice one O.G.

Does it stink as bad as I've been told?

Heard about this from some gardeners since this thread... Suppoosed to work well anyway!

All the best mate....

I bought some rhubarb but something in the garden ate it all, what ever it was is having a cracking feed at my expense, broccoli carrots cauliflowers beans potatos butternut squash outdoors gardeing sucks , got some cracking garlic and gooseberries though.

WTF was that

how long can the rhubarb solution be stored after its strained and bottled?

if it lasts a while i'll get a batch on the go tomorrow what quantity of shredded leaves do you use per L of water?