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Plant Disease

A ripe tomato on a tomato plant.

Tomato Problems and Solutions

Tomatoes are one of the most planted garden crops in the US and remain a staple of most vegetable gardens across central Illinois. Illinois Extension receives many questions about these plants and their care each year, with most questions centering on controlling some common ailments.  From dead...
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A mature American elm at Morton Arboretum in Lisle, IL

Breeding elms to combat Dutch elm disease

Over this past week, the fall weather has brought bare branches to the previously color-filled canopies of so many trees in the landscape.  As the autumn leaf drop has progressed, there are several elm trees that I pass each day which have held onto their fall color and really look spectacular as...
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This purple coneflower is infected with aster yellows, which produce odd and deformed flowers that can actually be interestingly attractive at times, but must be controlled to limit infection of other susceptible species in the landscape.

Aster Yellows on Coneflower

It is always interesting to observe plant diseases and try to unravel the mystery of how a particular plant became infected and to look toward solutions.  So many of these ailments have an incredibly fascinating path to infection, often including multiple species when you consider the pathogen,...
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This pin oak tree tested positive for bacterial leaf scorch and displays the most distinctive symptoms characterized by brown leaf margins, a colorful band and green tissue along leaf veins.

Bacterial Leaf Scorch Infecting Illinois Oaks

Shade trees are some of the most valuable plants in most urban landscapes.  They provide energy saving shade as well as valuable habitat for wildlife in a sometimes otherwise inhospitable built environments.  However, a mature shade tree takes considerable time to develop the canopy and branch...
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The alien-looking fingers protruding from these crabapples release spores that can infect trees in the juniper family to perpetuate cedar-apple rust disease.

Plant Pathogen Spread

Whether its fungi, bacteria or even viruses, one of the most important aspects of plant disease management is stopping or limiting the spread of infectious pathogens.  I have always been fascinated by the way these tiny organisms, rarely visible to the naked eye, make their way through nature to...
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Sycamores across central Illinois are late to leaf out this year due to a commonly occurring fungal infection.

Sycamores and Anthracnose

It has been another difficult spring for sycamore trees across central Illinois as near bare canopies of this tree stick out among the fully developed leaves of neighboring trees.  However, this doesn’t necessarily spell doom for your sickly looking sycamore.  It’s all caused by naturally occurring...
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This rhododendron shoot is infected with the pathogen Phytopthora ramorum, displaying the typical symptoms of ramorum blight. PC UI Plant Clinic

Rapid Response to Ramorum Blight

In early July, the Illinois Department of Agriculture submitted a press release detailing the detection of a new pathogen in Illinois that threatens our native oaks. This non-native pathogen is the causal agent for a very serious disease known as sudden oak death. However, there may be some good...
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Tomatoes are one of the most planted garden crops in the US, with several common problems here in central Illinois that can be managed through fairly simple cultural practices.

Tomato Care

Nothing beats a homegrown tomato!  Even when in season, the store bought varieties just cannot compare to a fully ripe tomato harvested at its peak from your own garden.  So many gardeners across American choose tomato plants for their garden each year for this reason, making it the most planted...
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Black Walnut

Anyone with a mature black walnut (Juglans nigra) on their property is likely aware that fruits are ripe now and the baseball-sized, green bombs are beginning to fall with each slight gust of wind or, at times, seemingly at random.  This native tree is prevalent throughout central Illinois...
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Sycamores

Our native sycamore tree (Platanus occidentalis) is known for its extraordinary exfoliating bark which peels off to expose the beautiful creamy white and greenish colors beneath creating a camouflage-like appearance.  This summer many area sycamores are shedding bark at alarming rates...
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Gardening with Natives

Native plants are typically defined as vegetation growing wild in an undisturbed area at the time that scientific records began.  Specific climate, soils and other environmental factors, define a plants native range.  Our area is fortunate enough to have a large diversity of both prairie and forest...
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Idea Garden Tropicals on the Move

On a cold, dreary day with misting rain last week a group of Master Gardeners met at the Idea Garden, in the University of Illinois Arboretum, for a ritual that has occurred for many years.  Each year, most plants in the “Tropicals Section” of the Idea Garden are removed from the ground and...
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