Spindle Galls; Unusual Growths On Linden Leaves Caused by Eriophyid Mites

What Are Galls? Galls are unusual growths or deformities of plant tissue caused by an organism; be it insect, nematodes, fungi, bacteria or viruses. The presence of these organisms initiates an increased production of normal plant growth hormones and these plant hormones cause localized plant growth. The gall-making organism feeds inside the gall. The appearance of the gall is unique to the gall maker and … Continue reading Spindle Galls; Unusual Growths On Linden Leaves Caused by Eriophyid Mites

Insect Pest of Boxwood…Boxwood Psyllid

Boxwood psyllid (Monarthropalpus flavus) are small, soft bodied insects that feed on the sap of boxwood. They are light green in colour and the nymphs are covered in whitish waxy secretions. These waxy secretions can make the boxwood appear to have dandruff. The nymphs feeding causes the leaves to curl over and cup; enclosing them in a protective shield safe from predators, weather and garden … Continue reading Insect Pest of Boxwood…Boxwood Psyllid

Honey Locust Plant Bug Damage And Control

Several Honey Locust trees here in Southern Ontario have been the target of small green bugs that have been distorting honey locust leaves and in some cases partially defoliating these trees. The main culprit has been the honey locust plant bug (Diaphnocoris Chlorionis). The honey locust plant bug (Diaphnocoris chlorionis) are approximately 3mm (1/8 inch) long when full grown and light green in colour. They pierce leaf … Continue reading Honey Locust Plant Bug Damage And Control

Red Bark Phenomenon

Red Bark Phenomenon is a fairly new occurrence here in North America. Scientists, horticulturalists and the like have been scrambling to learn more about this phenomenon as more and more trees are becoming affected. What they have learned so far is that the reddening of the bark is caused by a microscopic, filamentous green algae (Chlorophyta), that is believed to belong to the genus Trentepohlia. The … Continue reading Red Bark Phenomenon

Boxwood Leaf Miners

Boxwood leafminers (Monoarthropalpus flavus syn. Monarthropalpus buxi) are orangish gnat like flies that are a major pest of boxwood. Their larvae, which are small worm like maggots, feed inside of boxwood leaves causing blisters and puckering on the backside of the leaf and brown blotching on the upper surface. Premature defoliation of infected leaves occurs. In large numbers they can cause extensive and unsightly damage even … Continue reading Boxwood Leaf Miners

Japanese Maple Problems…Coral Spot Nectria Canker

What is Coral Spot Nectria Canker? Coral Spot Nectria Canker is a fungal disease caused by the fungus Nectria cinnabarina. These opportunistic fungi typically attack trees and shrubs that have been weakened by stress or injuries like mechanical injury, storm damage, insect feeding, animal damage, pruning, disease, frost cracks, cold injury or drought damage. Once the fungi gain entry to the plant they cause the … Continue reading Japanese Maple Problems…Coral Spot Nectria Canker

Botryosphaeria Canker of Red Twig Dogwood

Red twig dogwood species consisting of Cornus sericea, Cornus alba and Cornus sanguinea are prone to several fungal diseases and their coresponding fungi including; powdery mildew (Erysiphe pulchra), dogwood anthracnose (Discula destructiva), leaf spot (Cercospora cornicola and Septoria) and Botryosphaeria canker ( Botryosphaeria dothidea). Of these fungal diseases Botryosphaeria canker and dogwood anthracnose are both capable of producing cankers on the stems of dogwood. To … Continue reading Botryosphaeria Canker of Red Twig Dogwood

Crown Gall on Euonymus

Galls are abnormal growths that can appear on roots, stems, trunks or leaves. There are many woody plants that get galls and there are several different gall makers (causes for the gall formation); insects, mites, bacteria, fungi, or nematodes. The galls formed are unique to the gall maker and the genus or species it feeds on. For crown gall the disease is caused by a … Continue reading Crown Gall on Euonymus

Pine Needle Scale: Identification, Life Cycle and Control

Pine needle scale (Chionaspis pinifoliae) are very small, white, stationary insects found on the needles of pine (primarily ponderosa, mugo and scotch), spruce and occasionally, balsam fir, hemlock, and yew. They feed by inserting their stylet into the needles and sucking the juices out. This causes spotting to the branches. Badly infested trees may have a greyish appearance with needle loss. Left uncontrolled whole branches … Continue reading Pine Needle Scale: Identification, Life Cycle and Control

Mealybug Damage To Yews

Yews are a popular shrub in ornamental home gardens. Their deeply green foliage contrasts beautifully in the gardens spring, summer, fall and winter. Their slow growth habit and ability to take a hard pruning has made them a favorite for hedges and topiary for thousands of years. These beauties are also pricy and it is no wonder that homeowners want to protect their investment and … Continue reading Mealybug Damage To Yews

Juniper Blight

Juniper trees and shrubs are a popular choice in the ornamental home garden. These slow growing plants require little maintenance, are fairly drought tolerant, take full sun and are able to grow in a variety of soil types. They are fairly salt tolerant and make good road side plantings. In addition to this they are evergreens and provide year round beauty and interest to the … Continue reading Juniper Blight

Planting Near A Walnut Tree

When selecting plant material for a home garden it is important to first take inventory of the trees on your property and neighbouring properties. Trees like walnut can present a real challenge for gardeners. Not only do the plants you select have to deal with shade and strong competition for water and nutrients, (as with planting near any large tree), they additionally have to contend … Continue reading Planting Near A Walnut Tree

Viburnum Leaf Beetle

Viburnum leaf beetles (Pyrrhalta viburni), are a serious threat to many species of viburnum. They are voracious feeders with a long feeding season. Both the larvae and adults feed on viburnum leaves. The larvae skeletonize the leaves while the adults chew oblong holes in them. If their numbers are great enough they can completely defoliate a viburnum shrub, causing dieback that can lead eventually to … Continue reading Viburnum Leaf Beetle

Juniper Rust (aka) Cedar Apple Rust

Written by Kimberley Pacholko Updated on Sept. 25, 2021 Juniper Rust (Gymnosporangium juniperi-virginianae) better known as Cedar Apple Rust, s a fungal Disease requiring 2 years and 2 host plants to complete it’s life cycle. In the first group of host trees you have Apple, Quince and Hawthorne. In the second group you have Eastern Red Cedars and many varieties of Junipers. The disease can … Continue reading Juniper Rust (aka) Cedar Apple Rust

Fire Blight in the Ornamental Home Garden

Fire Blight caused by Erwinia amylovora, is a serious bacterial disease that affects many members of the rose family (Rosaceae), such as purple sand cherry, apple, crabapple, quince, pear, plum, mountain ash and more. The trees and shrubs that have been infected have the appearance of having been scorched by fire. The disease is systemic and spreads rapidly leading to extensive damage, even death. There is … Continue reading Fire Blight in the Ornamental Home Garden