Plant/Tree Health Services

Because the climate of Northern New Jersey is warm and moist, and because of the high population density of Union City, many tree diseases thrive here. If you know what diseases are common in your area, you can catch problems sooner and treat them faster.

Anthracnose

The diseases caused by Anthracnose affect: oak, maple, ash, sycamore, and London plane trees.

Symptoms of Anthracnose include: irregular brown or black patches along the veins of the leaves; leaves may begin to curl up or fall from the tree by late spring; you may find small cankers or dead twigs throughout the upper part of the canopy.

Anthracnose is caused by an anthracnose fungal pathogen that grows best in the cool, wet spring conditions common to the Hudson County area.

Recommendations for Treating Anthracnose:

• Apply professional-grade fungicides when buds break.
• Sanitize the area around the tree using rakes to remove and dispose of any fallen leaves that have been affected by the disease to help lower the number of fungal spores.
• Prune the tree to increase the amount of air flow.

Powdery Mildew

Powdery mildew affects: dogwood, crabapple, lilac, and other ornamental trees.

Symptoms of powdery mildew include: a thick, white or light gray dust that covers the surface of leaves; infected leaves are typically stunted and misshapen and fall from the tree prematurely.

Powdery mildew is caused by fungi that grow best in areas where the air is humid, the temperature is moderate, and the air is stagnant.

Recommendations for Treating Powdery Mildew:

• Apply fungicides immediately after you see the first signs of symptoms.
• Prune any vegetation near the tree to improve sunlight and air circulation.
• When planting new trees, select varieties of trees that are resistant to powdery mildew.

Bacterial Leaf Scorch

Bacterial leaf scorch affects: oak (Red, Pin, and White), elm, and sycamore trees.

Symptoms of bacterial leaf scorch include: the leaves look burned or scorched, especially along the edges; the scorch is typically separate from the rest of the healthy green leaf; symptoms typically appear in mid-to-late summer.

Bacterial leaf scorch is caused by a bacterium (Xylella fastidiosa) that is carried by xylem-feeding insects such as leafhoppers.

Recommendations for Treating Bacterial Leaf Scorch:

• There is no complete cure for bacterial leaf scorch; however, it can be treated using antibiotics injected directly into the trunk and deep root fertilizers to decrease tree stress; proper mulching and additional water during the dry summer months are important.

Root Rot (Phytophthora)

Root rot affects: yew, juniper, azalea, and other types of evergreen plants.

Symptoms of root rot include: yellowing of leaves, wilting, and thinning of the canopy even though the plant has sufficient water; upon inspecting the roots, they will be soft and dark instead of hard and white.

Root rot is caused by water molds that thrive in saturated soils in densely populated urban environments.

Recommendations for Treating Root Rot:

• Avoid overwatering the plant; improve soil drainage.
• For valuable plants, apply a fungicide soil drench.
• Remove severely infected plants to stop the spread of infection to surrounding plants.

Apple Scab

Apple scab affects: crabapple, apple, and hawthorn.

Symptoms of apple scab include: dull, olive-green to black velvety patches on the leaves and fruit; significant infestation leads to complete yellowing and premature loss of leaves by mid-summer.

Apple scab is caused by a fungus that survives the winter months on fallen debris and then rapidly multiplies during the numerous springtime rain showers in northern New Jersey.

Recommendations for Treating Apple Scab:

• Apply preventative fungicides beginning at bud swell and continuing until early summer.
• Thoroughly clean up any debris from fallen leaves in the fall to prevent continued disease cycles.

Fire Blight

Fire blight affects: pear (Callery/Bradford and ornamental), apple, and hawthorn.

Symptoms of fire blight include: branches that appear to be blackened and shriveled as if scorched by fire; young shoot tips often bend into a shepherd's hook shape.

Fire blight is caused by a highly contagious bacterium that is transmitted by wind, rain, and insects.

Recommendations for Treating Fire Blight:

• During the winter months, prune out infected branches 8 to 12 inches below the visible damage; it is essential to disinfect pruning equipment with alcohol or bleach between each cut to prevent the spread of the disease; do not prune diseased branches in the growing season.