There is no doubt that treatments with systemic insecticides can protect ash trees from the ravages of emerald ash borer (Agrilus planipennis) (EAB).  However, insecticide treatments against EAB will not produce super ash trees.  Treated trees are still susceptible to a range of pest and disease problems that were observed on ash trees long before EAB arrived on the scene.  This includes fungal leaf spots.

Fungal leaf spots on ash may be caused by two different fungi:  Mycosphaerella effigurata and M. fraxinicola.  The diseases associated with...

Guignardia leaf blotch of Aescelus produced by the fungus, Guignardia aesculi, is becoming evident on buckeyes and horsechestnuts in many areas of Ohio.  The fungal spores require moisture to spread to new growth in the spring and to germinate to initiate foliar infections.  Infections and resulting symptoms then progress rapidly during warm summer months.

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During our BYGL Inservice call this past Tuesday; Pam Bennett (Clark County) and Amy Stone (Lucas County) reported observing high grasshopper populations in southwest and northwest Ohio, respectively.  This is the time of year when most grasshoppers are still nymphs which may make identification a challenge.  However, the four most common grasshopper species found in Ohio landscapes include the Differential Grasshopper (Melanoplus differentialis), Red-Legged Grasshopper (M. femurrubrum), Green-Legged Grasshopper (M. viridipes), and the Carolina Locust (Dissosteira...

Insects belonging to the Hemipteran family Reduviidae are collectively known as assassin bugs.  The family includes over 160 species in North America and all are meat eaters.  The common name for the family clearly describes how these stealthy hunters make a living.  The bugs are equipped with piercing-sucking mouthparts that are used to inject paralyzing and pre-digestive enzymes into their prey.  They then suck the essence-of-insect from their hapless victims.

Assassin bugs pass through three developmental stages:  eggs, nymphs, and adults.  This is known as "incomplete...

I have received numerous reports and pictures from southern and central Ohio of heavy localized Japanese beetle (Popillia japonica) populations.  Infestations are not widespread; however, where they are occurring beetles are being found in high numbers feeding on a wide range of hosts from favorite foods such wild grape, linden trees, and roses to some unusual hosts such as oak.  Dan Potter (Department of Entomology, University of Kentucky) has also reported high populations in Lexington, KY.

Common bagworm (Thyridopteryx ephemeraeformis) populations crashed a few years ago in Ohio with this general defoliator becoming a rare find.  This changed last season with significant localized populations observed in many areas of the state and the trend appears to be continuing this season.  I've recently found several heavy infestations in southern Ohio with significant damage now becoming very evident.

It is a common misconception that bagworms only eat evergreens; however, the caterpillars can feed on over 130 different species of plants including a wide...

Rust diseases of plants may of course be devastating, from black stem rust of wheat which contributed to famine after World War I to cedar apple rusts which must be controlled by orchardists and (sometimes) landscapers today. Yet, it must be admitted, they are fascinating. They can be autoecious (occurring on only one host plant) such as may-apple rust commonly seen in spring woodlands, but often they must complete their life cycles on wildly different hosts, such as wheat & barberry, juniper & apple.

About a month ago I came upon a rust disease I had not...

Second generation larvae of the imported willow leaf beetles (Plagiodera versicolora) are munching the leaves of wild and cultivated willows in southwest Ohio.  This native of northern Europe was first found in the U.S. in 1915.  Since that time, it has become well established throughout most of the eastern and Midwestern states.  This beetle has a history of periodically achieving population outbreak densities and causing significant defoliation of its namesake host in Ohio.

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With apologies to William Blake and his 1794 publication of the deep-meaning “The Sick Rose” poem, it occurred to me that I was indeed deliberately trying to weaken the pictured rose (multiflora) by mowing in my back lot and continually chopping off the terminal shoot of this rose. In my case, I see this mowing as a metaphor for typically improper topping that I will negatively highlight in my pruning talk at the Cultivate 2016 program a week hence. For trees, top not, you clod-loppers: it releases adjacent buds resulting in hormonal imbalance and tufted, weak growth.

Probably a decade ago, I brought home a containerized tree, probably from a Secrest Arboretum Plant Discovery Day sale, perhaps as a gift from a friend. It was neglected in its container at the side of our house in northeast Ohio until my wife elbowed me into planting it on a day with little time and I stuck it a few feet away near some old spruce trees. I mostly forgot about it, maybe once a year wondering if this was a volunteer that had sprouted up or if I had planted it, until last year, at about 15 feet tall (yes, I am that unobservant and lazy), when I noticed this tree’s yellow...