Journal archives for June 2019

02 June, 2019

Plant pests, pathogens, and galls, why do we overlook them?

Over the last two years I have become particularly interested in observing plant pests, plant pathogens, and plant galls here in North America. Very often, finding them requires scanning plant life quite carefully as you progress slowly through a landscape.

In general we seem to have the habit of visually ignoring or avoiding looking at damage to plants. There is a sense that this kind of imperfection is "ugly" and unpleasant. There does not seem to be an awareness that damage to plants very often represents the survival work of other organisms, and that those organisms (viruses, bacteria, fungi, arachnids, insects, mollusks) can fairly often be identified to the species level by simply paying attention to the visual characteristics of the damage.

There is a parallel here. I have been interested in seashells since I was a toddler, but for many years I assumed that all the broken shells I saw on the beach were shells which had been whole when the animal died. I assumed that each shell had become broken in the process of being washed up, perhaps by being knocked against rocks, or dashed together with other shells in the waves.

But then I read Geerat Vermeij's 1993 book, "A Natural History of Shells". On page 94 he recounts how, on a beach in Guam in 1970, thanks to a comment from Lucius Eldredge, it dawned on Vermeij that damaged, repaired and broken shells are very often the result of predation. This insight struck him (and, in turn, me) with considerable force.

The damaged plants I see are like the broken shells, not to be avoided with disgust, but to be carefully "read" for the information they contain about the web of life.

Posted on 02 June, 2019 13:51 by susanhewitt susanhewitt | 27 observations | 16 comments | Leave a comment

26 June, 2019

Fungal pathogens on plants in NYC

This year the spring and early summer in New York City has been very wet -- we have had a great deal of rain, and this seems to have favored the growth of fungi.

Here is a list of taxa of fungal plant pathogen species which I believe I have observed in NYC. This is very much a work in progress, so please forgive errors of various kinds, as well as general mistakes and incompleteness. I hope to add to this post and refine the text over time.

NOTE: Apologies to any real plant pathologists reading this: I am not doing any microscope work or culturing, so all of my IDs are just guesses based only on the appearance and symptoms of the affected leaves. Because of this, some (or perhaps many) of my IDs will turn out to be unreliable or just plain incorrect. As a result, in some cases the icon images for the species will have to be changed.

Some of these fungi were observed living in/on wild species of plant, and some were observed on cultivated plants. So far I have searched parks, gardens, street trees, and a small Urban Farm.

This first version is gleaned from the list of species currently in the project New York Mycological Society -- Fungi of NYC.

Mulberry leaf spot (on mulberries) -- Cercospora moricola
Pear Rust (on Callery Pear) -- Gymnosporangium sabinae
Black Rot (on Boston Ivy) -- Phyllosticta amplicida
Black Tar Spot (on maples) -- Rhytisma acerinum
Cercospora Leaf Spot on Hydrangea (on hydrangeas) -- Cercospora hydrangea
Red Dock Spot (on docks) -- Ramularia rubella
Quince Rust (on Serviceberries and others) -- Gymnosporangium clavipes
Hollyhock Rust (on garden hollyhocks) -- Puccinia malvacearum
Black Spot (on garden roses) -- Diplocarpon rosae
. . no common name (on Virginia Creeper) -- Phyllosticta quinquifolia
Spindletree Powdery Mildew (on Japanese Euonymus) -- Erysiphe euonymicola
. . no common name (on Wild Vetch and on Board Beans) -- Didymella fabae
. . no common name (on Common Mugwort) -- Puccinia tanaceti
Black Spot of Elm (on Elms) -- Stegophora ulmea
. . no common name (on Eastern Cottonwood) -- Drepanopezia brunnea
Lettuce Anthracnose (on Prickly Lettuce) -- Microdochium panattonianum
Dogwood Anthracnose (on Dogwood) -- Discula destructiva
Sycamore Anthracnose (on Plane trees) -- Apiognomonia veneta
. . no common name (on Heavenly Bamboo) -- Pseudocercospora nandinae
Cherry Leaf-Blight (on wild cherry) -- Blumeriella jaapii
Juniper-apple Rust (on Eastern Juniper) -- Gymnosporangium juniperi-virginianae
Bullseye Leaf Spot (on Japanese Maples) -- Phyllosticta minima
Powdery Mildew on Clover (on Red Clover) -- Erysiphe polygoni
Violet Rust (on wild violets Viola sororia) -- Puccinia violae
Oak Anthracnose (on white oak group) -- Apiognomonia errabunda
Cercospora Leaf Spot of Swiss Chard, Beets, and Spinach (on Beets) -- Cercospora beticola
Cercospora leaf Spot on Clover (on red clover) -- Cercospora zebrina
Hellebore Leaf Spot (on garden hellebore) -- Coniothyrium hellebori
Hypericum Rust (on garden St. John's Wort) -- Melampsora hypercorum
Ash Anthracnose Fungus (on Ash street trees) -- Gleosporium aridum
Peony Red Spot (on garden peony) -- Graphiopsis chlorocephala
. . no common name (on gardened Trilium) -- Urocystis trillii
Coryneum Blight (on Purple-leaved Plum) -- Wilsonomyces carpophilus

These species are only the ones where I think I could come up with an ID. I have many more about which am currently clueless, and which will probably have to remain so indefinitely for lack of lab work.

Posted on 26 June, 2019 13:26 by susanhewitt susanhewitt | 7 observations | 0 comments | Leave a comment

Leafminer species in NYC

To quote the Wikipedia article on leaf miners, "A leaf miner is any one of a large number of species of insects in which the larval stage lives in, and eats, the leaf tissue of plants."

If you are not yet familiar with leafmines, but are curious to see some, start looking carefully for white squiggly lines or whitish blotches on leaves of all various kinds of plants, both wild and cultivated.

On this page I am compiling a list of the leaf miner species that I have observed in NYC. The species identifications are almost entirely thanks to the generosity and brilliant ID-ing work of leafminer expert Charley Eiseman, @ceiseman.

Just a reminder here that leaf mining is an ecological niche, not a taxon. All leaf mines are created by insect larvae, but as Charley points out: "In North America [leafminers] include at least 40 families of moths, 10 families of flies, 6 families of beetles, and 2 families of sawflies." It's also worth saying here that despite the common name, sawflies are not flies; instead they are related to wasps.

Most of the leafminers on this list are larvae of small flies, but so far I have observed several that are moths (microlepidoptera), one which is a chrysomelid beetle, and one which is a sawfly. The taxa other than flies I have put in boldface.

Orache Leafminer (on Lambs Quarters) -- Chrysoesthis sexgutella -- moth common name (on Asteraceae) -- Liriomyza eupatorii -- fly
Cabbage Leafminer (on Garlic Mustard) -- Liriomyza brassicae -- fly common name (on Asteraceae) -- Liriomyza eupatorii -- fly
Mallow Leafminer (on mallow family) -- Calycomyza malvae -- fly
Burdock Leaf Miner (on burdocks) -- Liriomyza arctii -- fly
Columbine Leafminer (on garden columbines) -- Phytomyza aquilegivora -- fly common name (on White Clover) -- Liriomyza fricki -- fly common name (on Elm leaves) -- Agromyza aristata -- fly common name (on White Snakeroot) -- Calycomyza eupatoriphaga -- fly
Elm Leafminer (on elms) -- Fenusa ulmi -- sawfly common name (on elms) -- Agromyza aristata -- fly common name (on Seaside Goldenrod) -- Nemorimyza posticata -- fly common name (on Asteraceae) -- Calycomyza promissa -- fly
Goldenrod Leaf Miner (on Seaside Goldenrod) -- Microrhopala vittata -- beetle
Morning-glory Leafminer (on Convolulaceae) -- Bedellia somnulentella -- moth common name (on Chenopodiaceae) -- Chrysoesthia lingulacella -- moth
Milkweed Leafminer (on Common Milkweed) -- Liriomyza asclepiadis -- fly
Leaf Miner on Tulip Tree (on Tulip Tree) -- Phyllocnistis liriodendronella -- moth common name (on goldenrods) -- Calycomyza solidaginis -- fly common name (on garden columbines) -- Phytomyza aquilegiana -- fly common name (on Amaranthus blitum) -- Pegomya wygodzinskyi -- fly
Poison Ivy Leaf-miner (on Poison Ivy) -- Cameraria guttifinitella -- moth
Grass Sheathminer (on a weed grass) -- Cerodontha dorsalis -- fly common name (on buttercup) -- Phytomyza ranunculi -- fly common name (on Bull Thistle ) -- Scrobipalpa acuminatella -- moth
??Brassica Leaf Miner (on radish) -- Scaptomyza flava -- fly
Locust Digitate Leafminer Moth (on Black Locust) -- Parectopa robinella -- moth
Chrysanthemum Leafminer (on Asteraceae) -- Phytomyza syngenesiae -- fly common name (on Eastern Cottonwood) -- Stigmella populetorum -- moth
??no common name (on a Rumex species) -- Pegomya bicolor -- fly common name (on Groundsel Tree) -- Bucculatrix ivella -- moth common name (on elm) -- Stigmella apicialbella -- moth
Daylily Leafminer (on daylily) -- Ophiomyia kwansonis -- fly
.. no common name (on White Snakeroot) -- Liriomyza eupatoriella -- fly common name (on Penstemon) -- Phytomyza penstemonis -- fly common name (on legume) -- Micrurapteryx occulta -- moth common name (on Asteraceae) -- Ophiomyia parda -- fly common name (on Mock Orange) -- Liriomyza philadelphivora -- fly common name (on a goldenrod) -- Phytomyza solidaginophaga -- fly common name (on Asteraceae) -- Ophiomyia carolinensis -- fly
Hellebore Leaf Miner (on hellebore) -- Phytomyza hellebori -- fly common name (on magnolia) -- Phyllocnistis magnoliella -- moth

On June 28th 2019, there were a total of 41 species on this list, but I am adding more
species to this list as time goes by.

Update, July 10th 21019. I added: common name (on Magnolia) -- Phyllocnistis magnoliella -- moth common name (on Columbine) -- Phytomyza aquilegiana -- fly

Update July 18th 2019, I found: common name (on American Holly) -- Phytomyza glabricola -- a fly


June 23rd: Yucca Beetle (in petals of Yucca filamentosa) -- Carpophilus melanopterus (beetle).

July 20th: Purslane Sawfly (on Common Purslane) -- Schizocerella pilicornis

July 26th: No common name (on Salix) --

Posted on 26 June, 2019 16:46 by susanhewitt susanhewitt | 6 observations | 1 comment | Leave a comment