Adult Japanese Beetle

Japanese beetles are a serious invasive insect pest of both turf and ornamental plants. Introduced to the U.S. from Japan in 1916, Japanese beetles have no natural enemies in Minnesota to naturally control the population. Beetle grubs are white and ‘C’ shaped, about 3/4 to 1 inch in length while adult beetles are approximately 3/8 -1/2 inch in length with a metallic green head with dark tan wings. Please note that there are other grubs and adult beetles that look similar but may not cause the type of damage that Japanese beetles cause. Therefore it is important to contact an ISA Certified Arborist for correct identification.

Both larvae and adult Japanese beetles cause damage. The larva, or grubs, damage turf by consuming grass roots creating dry patches that easily lift up. Look in nearby healthy turf for grubs just under the soil.  Granular insecticide applications followed by watering in mid May to early June can provide good control for grubs.

Skeletonized leaf from Japanese beetle feeding

Adult Japanese beetles cause significant damage to foliage of many types of trees, shrubs and plants. Trees susceptible include: linden, paper birch, crabapples, and elm. Shrubs and perennials susceptible include: grapes, roses and hollyhock. Adult beetles feed beginning in early July until late August creating a ‘skeleton-like’ appearance on the leaves with only leaf veins remaining.

Here’s what we can do

Shadywood Tree Experts can help maintain your trees with the use of insecticide applications and annual fertilization. When you sign up for plant health care from Shadywood, we administer the recommended protocols for disease prevention control to keep your trees healthy. With each visit, our arborists assess trees for overall health.

Linden tree showing symptoms of Japanese beetle damage at the top of leaf canopy

Additional things you can do to maintain the health of your tree

Water trees regularly using a hose or lawn sprinkler for at least an hour every one to two weeks if there has not been adequate rainfall. Mulch root systems when possible, using natural wood chips to protect the trunk, condition and improve the soil, and to conserve soil moisture.  If you see anything that doesn’t look right, have your trees inspected by one of Shadywood Tree Experts International Society of Arboriculture Certified Arborists.

Dutch Elm Disease

Dutch elm disease is a destructive fungal disease of elm tree that has caused the loss millions of elm trees in USA. Brought over from Europe in the 1930’s, the Dutch elm disease fungus, Cerosystis ulmi, has infected and killed most of the stately elms that once lined most streets in the United States. Today, only a small portion of the once mighty elms remain and are still being infected and killed by Dutch elm disease.

Dutch elm disease is spread in two ways. The primary way is by native and the European elm bark beetles. These beetles begin their lives in dead and dying elms, a requirement for reproduction. As beetles feed under the bark, the fungal spores of Cerosystis ulmi adhere to the bodies of newly emerging beetles. These beetles then fly to neighboring elms and begin feeding and spreading the disease.

The second way Dutch elm disease is spread is through underground root grafting. When plants grow in close proximity to one another, their root systems can actually grow together, forming one very large combined root system. If one tree becomes infected and is not removed before the fungus grows down to the root system, it will spread to the adjoining tree and infect it.

There is an effective root flare injection treatment to prevent the beetle spread of Dutch elm disease. Unfortunately, there is no easy treatment to prevent the root graft transmission, aside from physically severing the root systems using a vibratory plow.

What Shadywood Tree Experts Recommends for elm trees

We can help maintain your trees with the use of systemic fungicide trunk injections and annual fertilization. When you sign up for plant health care from Shadywood, we administer the recommended protocols for disease prevention control to keep your trees healthy. With each visit, our arborists assess trees for overall health.

Additional things you can do to maintain your elm tree’s health

Water trees regularly using a lawn sprinkler for at least an hour (soaking) once every one to two weeks to minimize moisture stress. Mulch root systems when possible, using natural wood chips to protect the trunk, condition and improve the soil, and to conserve soil moisture.  If you see anything that doesn’t look right, have your trees inspected by one of Shadywood Tree Experts International Society of Arboriculture Certified Arborists.