Southern pine species such as loblolly, longleaf, shortleaf, and slash cover much of the 
southeastern U.S., and are a critical component of the region’s economy.  Loblolly pine is the 
most widely planted species in the southeastern...

Climate change and biological invasion are major threats to biodiversity, but their combined effects haverarely been quantified. The introduction of congeneric non-native species, in particular, can be especially problematic for native species due to...

A policy document developed to balance the public garden mission of holding diverse horticultural collections with the conservation mission of preserving natural areas and the broader environment.

Learning to distinguish the symptoms of lightning strikes is a valuable tool for arborists, landscapers, pest control companies, and gardeners. The symptoms may be confused with other causes such as lethal yellowing disease (Candidatus palmae...

Invasive plant introductions are increasing globally, and trends in human activity suggest these increases will continue. Although we know much about interactions between invasive herbaceous plants and arthropod communities, there is a dearth of...

Since a devastating fungal blight popped up in the Bronx Zoo in 1904 and went on to kill at least 3 billion chestnut trees, North American forests have been swept by one plague after another, including a fungus that kills elms and an aphidlike insect...

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Since the Ontario Cosmetic Pesticide Ban of 2009, Royal Botanical Gardens (RBG) had struggled to maintain its Rose Garden to world class standards. Ontario's 2017 sesquicentennial celebration afforded the perfect...

Emerald ash borer (Agrilus planipennis) was first discovered in southeastern Michigan in 2002. Accidentally introduced on solid wood packing material from Asia, EAB has since spread to nearly all states within the native North American range of its...

Six elements are required in small amounts for the growth and development of plants. These are referred to as micronutrients: iron (Fe), manganese (Mn) copper (Cu), zinc (Zn), molybdenum (Mo), and boron (B). Only two of these, iron and manganese, are...

Needlecast and needle blight are terms applied to a variety of foliage disorders of many coniferous species. These diseases are usually more severe on young trees or on trees growing outside of their natural range. Disease severity and corresponding...

Sonic tomography, or the use of sound waves to detect decay in trees, is a relatively new technology available to arborists.  This technology uses the differential speed of sound as it moves through solid wood, decayed wood, or hollow space to create a...

The horticultural trade relies on healthy plants to flourish. However, its very nature
means that it is also a key pathway for the introduction and spread of plant pests and diseases.
These pests and diseases threaten horticultural...

Thousands of trees are struck by lightning every year. These trees will have varying degrees of damage ranging from complete shattering and destruction of the tree, to a slow lingering death, to virtually no apparent damage at all (Figure 1). When...

European ash is a significant tree commercially, ecologically, and culturally. It is currently
threatened by two invasive species, the fungus that causes ash dieback and
the emerald ash borer (EAB) beetle. We show that saplings of...

Conifers are commonly planted in North America to provide year-round screening, as windbreaks or as focal trees in the landscape. However, conifers including certain species of spruce, pine, hemlock, cedar and fir planted in northern areas of North...

Oak decline is a slow-acting disease complex that involves the interaction of biotic and abiotic factors such as climate, site quality and advancing tree age. Oak decline occurs more commonly among red oak species, but white oaks are susceptible as...

Interception of potential invasive species at ports-of-entry is essential for effective biosecurity
and biosurveillance programs. However, taxonomic assessment of the immature stages
of most arthropods is challenging; characters for...

Ice or snow loads can cause branch breakage or failure of entire trees and shrubs. Branches or entire trees that fall in storms can impact homes, vehicles, power lines and block roads. After a storm, the first priorities are safety and restoration of...

• Many exotic plant pests and pathogens are unknown prior to their establishment, making prevention and management difficult.
• Sentinel plantings to detect pests and pathogens prior to introduction provide information about the likelihood
...

The invasive hemlock woolly adelgid (HWA) has decimated hemlock stands across much of the eastern United States, and presents a significant threat to all eastern hemlock in Canada across Ontario, Quebec, New Brunswick, Nova Scotia, and Prince Edward...