Pests and Diseases

The telltale signs of various tree diseases and insect infestations are often most evident in summer. Populations of many types of scales, mites, and aphids are particularly noticeable at this

The hemlock woolly adelgid is a sap-sucking insect that feeds specifically on hemlock trees. As the insects feed, they damage the tree by removing sap and disrupting the flow of

The polyphagous shot hole borer is a recently introduced, non-native beetle that is having a devastating impact on landscapes, forests and agriculture in southern California. This insect pest bores into

After the cold, dark weather of winter, we are all looking forward to spring! Flowers will be blooming.  The birds will be singing. And while spring brings new life to

Brood X is on its way. This is one of the largest broods of periodical cicadas, and the insects will soon be seen in a number of states including Delaware,

Sometimes when a non-native species is introduced to a new environment there is a devastating result. Whether the invasive species is a plant, animal, or pathogen, the presence of these

Everyone is outside these days, taking long walks in the park or on hiking trails and creating new spaces in their own backyards. It’s amazing to see people embracing the

Be on the lookout for bagworm bags on juniper, arborvitae, spruce, pine, cedar and lots of other conifers and deciduous plants. Bagworm is a moth, which in its larval stage,

Lots of scale insects are active during the heat of summer, but some of these tiny pests are just now beginning to hatch and will continue causing tree and shrub

Oak is one of the most common tree species in the northern hemisphere. Often seen as a symbol of strength and wisdom, oaks are well-known for their longevity and adaptability.

Aphids are small, sap-sucking insects. Some of them feed on more than one type of plant— for example, apple grass aphids feed on young new leaves and blossoms of apples

Oystershell scale (Lepidosaphes ulmi) belongs to a group of insects called the armored scales. The “armor,” is produced by a waxy secretion combined with the insect’s own body cast during

Over the past decade, spruce trees have suffered an abundance of issues. All species of spruce, including Colorado blue and white spruce, are being affected, but particularly concerning is the

Boxwood blight is caused by the non-native fungus Calonectria pseudonaviculata. American and English boxwood (Buxus sempervirens) are most susceptible to this disease whereas many Asian species of boxwood, and hybrids

Pear trellis rust is caused by the fungus Gymnosporangium sabinae. It was introduced into the United States from Europe in the 1990s and has been progressively spreading through states in