In message , Martin Brown
writes
On 24/04/2021 14:52, Andy Burns wrote:
Harry Bloomfield wrote:

In my sprayer I have some diluted Rosate 360 TF according to
instructions, left over from last year. Will it still work this year
please, or do I need to make up a fresh batch?
I had a sprayer half-full of diluted glyphosate that had been
sitting over winter, I also wondered if the active ingredients might
have degenerated, sprayed the weeds on Monday and they're looking very
dead already.

Is that "glyphosate" the active ingredient or glyphosate the brand?
The two are sadly no longer the same

Proper glyphosate kills green plants by screwing up a key part of their
photosynthetic pathway and they turn a characteristic orangy yellow
after 1 to 2 weeks from application. Stone dead at three weeks. I don't
normally expect to see proper glyphosate at standard dilution take
effect within the first week. Sometimes I use it more dilute to allow
time for translocation into weeds with extensive roots like ground elder.

Unfortunately there are now branded "glyphosate" products on offer with
all sorts of other active ingredients in to make them faster acting for
the consumer market.

I suspect it will lose some activity when stored diluted in oxygenated
water but it is more the pesticides and fungicides that degrade rapidly
by hydrolysis that need to be used immediately after dilution.




--
Tim Lamb