Diagnostics: Coloring Outside The Lines

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It’s summertime, and diagnostics is never easy. As Pelinor of Buckland intoned: “Diagnosis of the colourful maladies of the plantes of the heathe and of the moores is Woman’s and Man’s most pressing calling, penetrating to the very hearte of darkness of Naturum gonne bad.” This struck me this past week as I contemplated the 85th Ohio Plant Diagnostic Workshop coming up in two weeks (see below)…And as I considered the spectrum of colors we encounter in diagnostics.

Purple Haze. On a walk yesterday, I came upon some goldenrod with roundish patches of lavender-purple on the leaves. A fungus? Yes and no. It was an interesting combination of the fungus Botryosphaeria dothidea housed within a gall (abnormal plant growth caused by a gall maker) induced by a midge fly, Asteromia carbonifera.


Gall on goldenrod
Lavender-purple galls caused by a midge fly on goldenrod leaves.


I have noticed this type of gall (though always with white and blackening appearance) for over 40 years, but I know most of the details of this from an outstanding, detailed bygl-alert by Joe Boggs of September 19, 2016. (https://bygl.osu.edu/node/574).


As Joe noted: “The galls appear as white, circular to elongate slightly raised structures on both the upper and lower leaf surfaces.  As the galls mature, they develop a faint black ring near the outer edge making the galls look target-like…the midge fly and the fungus have an obligate mutualistic symbiotic relationship meaning that the two live for the mutual benefit of one another and the relationship is so strong that without the fungus, the flies could not develop on goldenrod, and vice versa.” 


“ Indeed, the female flies carry spores of the fungus in specialized structures (mycangium) in their terminal abdominal segment.  When the flies insert eggs into the goldenrod leaf tissue, they also inoculate the plant with the fungus.”  There is more from Joe on this insect-fungus partnership and I encourage you to take a look at the 2016 alert, but for me, my catalogue of knowledge shall now include the color purple.


Speaking of purple, there are still a few more weeks, at least up in northeast Ohio to enjoy the electric ladyland of ironweed flowers.


Ironweed flowers
Ironweed as seen yesterday in Fairlawn Ohio.


A Brownian Motion of Larch. The past two summers my compatriots and I noticed a larch tree in Wooster with erratically twisted stems and needles and browning on many needles. What was happening? By way of background, larch itself is a conundrum for the uninitiated (as once was I) in that it is a “deciduous conifer” with cones and needles, but naturally losing its needles each fall.

Considering the twisting and browning though, I wondered, is this twisting normal for this plant?  After all: “What Is The Plant?” and “What Is Normal for the Plant?” are the first two questions of the 20 Questions of Plant Problem Diagnostics (ohioline.osu.edu/factsheet/plpath-) our OSU team have developed. So, we looked at the tree carefully, reviewed our memories and Google, and began to speculate (later confirmed) that this was Larix kaempferi ‘Diana’, a contorted Japanese larch. Quite a lovely and interesting plant.


'Diana' Japanese larch
Larix kaempferi 'Diana'


The browning of needles?  As we looked carefully, we saw that the browning was associated with scarring by, and this was subsequently also confirmed by multiple sitings of, the beasts themselves, Japanese beetles. This brings forth another of our early questions: “What Are Common Problems of the Plant?” One of my favorite truisms: “You don’t know until you know”.


Japanese beetle damage on Japanese larch
Japanese beetle damage on Japanese larch.


A Reddening of Sumac. Last week we had a “Common and Uncommon Pests of Trees” program at OSU-Mansfield and in the glistening aftermath of a day of heavy rains I strolled about the parking lot and espied some reddening of foliage on the sumac growing along woods-edge. Everywhere there was reddening of the upper leaf surface there was a misshapen pale yellow glob-like gall underneath. 


Aphid galls on sumac
Aphid galls on sumac in Mansfield earlier this week.


Pop open these galls and exploding into the air are scores of the aphid species that reprogrammed plant genes (turned some on and some off) to create a home for the aphids as they developed. The aphid (Melaphis rhois) causes this sumac aphid gall. The reddening was a sign of the horrors within. Fortunately (this is not poison sumac), it just looks abnormal; the sumacs are perfectly healthy. Keep your eye out for this interesting trifle, with the early reddening of the upper leaf tissue as your clue.


Effects of aphid galls on sumac
Aphid galls on sumac, with associated leaf reddening.


Aphids within gall on sumac.
The aphids within, the gall on sumac.


Again a bow to Master Boggs.  He dealt with this gall in detail (https://bygl.osu.edu/node/1112), but another truism is that you can never get enough of a weird thing, and we all know that repetition is part of learning, which is why the Diag-Mosh-Tics component of sample sharing is an essential part of our diagnostic workshops.


Sumac gall with alien face
A weird gall in sumac; the picture taken by Joe Boggs, himself weird, with Jim Chatfield superimposed, an even weirder scene. Be afraid...Very afraid.


Orange is the New Green.  I was at a friend’s house earlier this week, admiring their new landscape, They had installed dogwoods and hydrangeas, oaks and redbuds. Virtually all were doing well; I, chanelling my inner plant pathologist, noted a few minor problems, but life in their landscape was good.  They also had a new lawn for their new home, complete with a mix of ryegrass, fescues and bluegrass.


Turfgrass rust spores on mower
Orange spores of a turfgrass rust fungus adhere to the mower.


Rust spores on sandals
Spores of a tufgrass rust fungus on sandals.

As we chatted by the cars prior to my departure, what pathology was this – feet and sandals and shoes and the mower were…orange. They were not amused. And they were only partially convinced that this was not some fungus from outer space. Not to worry, though, it was only one or more of the common turfgrass rust diseases, occurring on the bluegrass and ryegrass. Naturally, these rust fungi do not infect humans, but the spore masses spread by wind and mowers and feet to lawns everywhere.

The overall condition of the lawn was good, it did not have a sickly, yellow-green look to it, so the recommendation is to do all the things that keep the turf healthy: proper mowing and fertilization and general reseeding where necessary will keep the lawn healthy.  Not rust-free in this or subsequent years, but healthy, as this disease is not that severe.


Turfgrass rust spores on shoes
For a day I had a new pair of rusty orange shoes.


A Whiter Shade of Pale. To gardeners, white areas on leaves bring to mind the powdery mildew fungi that affect rose, zinnia, lilac, turfgrass, and on and ever anon. One of the keys to diagnosis, though is to look closely. There is an annual tradition at the Ohio Agricultural Research and Development Center in Wooster, a planting of flowers spelling out O-A-R-D-C.   The planting for some reason is in the colors of scarlet and as close to being gray as possible.  Who knew?


Dusty Miller leaf
The leaf of a Dusty Miller plant.


For years the scarlet was wax begonias. This year it is celosia. Quite attractive. The gray was and is – Dusty Miller, Senecio cineraria.  If you did not know the plant you might think the leaves were covered with powdery mildew. Instead, this is just the hairs of the leaves that give the name of Dusty Miller to this plant.  Most gardeners know this and would not mistake this appearance for a powdery mildew infestation, but, remember: You Do Not Know Until You Know. 


Celosia and Dusty Miller together.
Red celosia and Dusty Miller together.  Sort of scarlet and gray.


Celosia and Dusty Miller at the OARDC in Wooster Ohio
O-A-R-D-C in flowers.


Tar Spots of Maple.  Both the larger aggregates of tiny small tarry spots surrounded by yellow halos caused by the Rhytisma punctatum  fungus on Norway maple and the dense consolidated tar spots on red and silver maple caused by Rhytisma acerinum are noticed this time of year. But do not fear: as Wayne Sinclair of Cornell once noted: “Tar spot of maple is one of the most spectacular – and least important diseases of maple."


Tar spots of maple.
Tar spots of maple: Rhytisma acerinum  on silver maple and Rhytisma punctatum  on Norway maple.


Purple and Gold.  Finally, some colors not associated with suspected problems, but rather the proud colors of Ashland University. Lola Lewis of the Ohio Department of Natural Resources Division of Forestry, Toby White, the grounds superintendent of Ashland University and I spent a day recently discussing the idea of Ashland University becoming a Tree Campus USA. It was a great visit to their very well-landscaped campus, from the planters and baskets along the Rybolt Corridor to Toby’s landscape design touches throughout, to lovely shingle oaks and Austrian pines.


Purple Prince crabapple and Old Abe eagle at Ashland University
'Purple Prince' crabapple and Old Abe eagle at Ashland University. Purple and Gold.


Their school colors are purple and gold, reminding me of my high school days and the purple and gold of the Lancaster Ohio Golden Gales. Particularly pleasing on the Ashland College campus was Toby using Purple Prince crabapples in the foreground of the Ashland College Eagle, in this “Case” ‘Old Abe’. These eagles are quite a tradition at Ashland County; visit the campus and see and read about the eagles in various sizes and with varied monikers throughout the grounds.


One Final Sleuthing Example.  My wife and I took a walk last Saturday evening in Tallmadge, Ohio and after enjoying the bustle of the street fair in Tallmadge Circle we strolled through the historic Old Tallmadge Cemetery. I noticed a gravestone for one Yule Biggs: 1886-1941. Interesting first name. Ever the deductive reasoner, I wondered what day Yule was born…you guessed it!


Yule Biggs gravestone
Holidays are coming.


Diagnostics is fun. Share in that fun and attend our 85th Plant Diagnostic Workshop to be held on Friday, September 7 from 10:00am to 4:00pm at the Miller Pavilion of Secrest Arboretum at the OSU’s Ohio Agricultural Research and Development Center in Wooster. The cost is $40 and you can register at https://agnr.osu.edu/chatfield by scrolling down to 85th Ohio Plant Diagnostic Workshop. And that program the day before is “Top Performing Herbaceous Plants for Ohio” (same address as above for registration).  It features the ever over-the-top performing Pam Bennett and her minions. 


Enjoy a fine lunch, a trove of diagnostic samples, mostly of trees, shrubs, and herbaceous and annual flowers (as noted above, there is a separate workshop the day before focusing on those flowers).  Indoor and outdoor talks and walks. Spirited discussion of the diagnostic issues of 2018 and the 20 Questions of Plant Diagnostics shall ensue and music shall be blaring from the pavilion speakers.

And come hear about Sherlock Holmes and the Diagnostic Process. 

I know, my dear Watson, that you share my love of all that is bizarre and outside the conventions and humdrum routine of daily life.”     - Arthur Conan Doyle


And, who is this Pelinor of Buckland?