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).

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.

Concern over the use of pesticides in public areas, such as schools, daycare centers, and parks, has prompted some state and local governments to severely restrict or ban pesticides in these locations.

Sonic tomography, or the use of sound waves to detect decay in trees, is a relatively new technology available to arborists.

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.

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).

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

Conifers are commonly planted in North America to provide year-round screening, as windbreaks or as focal trees in the landscape.

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.

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