Re: [gardeners] Magnolia Soulangeana wilting problems
Dan Dixon (gardeners@globalgarden.com)
Fri, 10 May 2002 12:05:32 -0500
Ron Hay at ronhay@pacbell.net wrote:
> It might be a good idea. Find out, if you can every hear back from your
> county agent (ours in L.A. County has what amounts to a FAQ on
> voicemail!), if perhaps using some liquid fungicide, such as Funginex or
> Neem oil might help. I find Neem oil to be very beneficial in combating
> fungus on roses, FWI. Just a thought. Would never want to suggest
> anything that might do violence to your plants(s).
>
> Ron
>
I removed all the poplar mulch down to bare soil, for what it's worth. About
half of it had decayed anyway, plus we're getting of rain every day now,
so....
The ag. extension guy did finally return my call. Over the phone diagnosis
is iffy of course, but his guesses, in order of most to least likely, were
freeze damage (we had a very warm March, with hard freeze in early April),
unknown toxins being released by decaying poplar mulch (no clue what that
could be), allelopathic reaction to nearby walnut tree, magnolia scale, or
root disease. His opinion was that phytophthora fungus was possible but he
says it's rare around here. I see no sign of scale, or any other insects of
any kind. Not surprising since whole front yard was treated with Merit last
June. The walnut tree is about 50 ft away, and dripline is probably 20 ft
minimum. The magnolia has been growing happily there for 4 or 5 yrs now, so
I doubt it's the walnut. Freeze damage could be it; there are even suckers
growing up from the base of the trunk which look healthy (no wilt), which I
suppose might support this theory. The only perplexing thing is that another
saucer magnolia we have is doing great, and it's smaller and younger so you
would think it more suseptible to freeze damage.
Anyway, nothing much to do but wait and see what happens once the ground
dries out some. I may try a metalaxyl drench just for the heck of it. Ag
extension guy said fungicides may help although spores of fungus would
remain in there and fungus will return once conditions were again favorable.
Worth a try I suppose. Anyone have any how-to-do-it info on this?
Dan Dixon