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Sorry,



Saw the photos.  That’s not mites.

A lot of rice hulls – is that just on the surface, or in the mix.

Check media pH.



The cupping of the leaves has me stumped.



*From:* Water Management and Quality for Ornamental Crop Production and
Health [mailto:[log in to unmask]] *On Behalf Of *Altland, James
*Sent:* Thursday, August 9, 2018 7:35 AM
*To:* [log in to unmask]
*Subject:* Injury symptoms?



Hi everyone,



Sorry for the duplication of emails, I am sending this to two different
(and probably overlapping) listserves.



I visited a nursery yesterday to examine some injured Hydrangea
arborescense.  Photos are attached.  The third photo is actually of a weed
growing in one of the pots (horseweed, or Conyza Canadensis).  The weed is
also very symptomatic.  Please let me know if you have observed this injury
before.  Here is some background information based on my site visit and
interview with the grower:



·         The injury was uniform across the entire block of H.
arborescense.  All three cultivars of the species were affected, even
though they were in different locations throughout nursery (a very large
nursery).



·         H. paniculata was not affected, despite being located immediately
adjacent to the H. arborescense.



·         All of the affected plants were irrigated from the same water
source (pond with captured and recycled water).



·         Weigelia were also stunted, but did not display these symptoms.
All other crops, primarily evergreens of some sort, were NOT affected.



·         All of these plants were potted this year, with liners coming
from different sources.



·         Based on information from the grower, this was not 2,4-D,
dicamba, or any other phenoxy or auxinic herbicide.  These products were
not used on this location.



·         They have agronomic neighbors, but again, the pattern was very
uniform across very large blocks of plants at several locations throughout
the nursery.  Drift from a neighbor does not seem to be responsible.



Any thoughts or opinions?  I am tracking down several herbicide-related
possibilities with my weed science colleagues.  But I didn’t want to rule
out other horticultural causes.  Please let me know if you’ve seen this
type of injury before, and if so, what potential causes were identified.



Thank you,



James



James Altland

220 FABE Building

OARDC

1680 Madison Ave.

Wooster, OH  44691

330-263-3870







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