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Hello Mid-Ohio Valley farmers and gardeners! This week I want to talk about Tree-of-Heaven (Ailanthus altissima), an invasive species from Asia. It has been in the news lately because it is a major host plant of the spotted lanternfly (Lycorma delicatula). First detected in Pennsylvania in 2014, the spotted lanternfly has since been found in several other states, including multiple counties in West Virginia.

We can now include Wood County. This pest was detected this summer, and the WV Department of Agriculture is currently taking control measures. Be on the lookout for this invasive insect in the Valley.

Spotted lanternfly adults may be present from July through early November and are easily identified. The outer wings are grey with black spots and have a brick-like pattern at the wing tips. The hidden underwings have brightly contrasting large patches of red, black, and white. The legs and head are black. The abdomen has broad black bands, with yellow on the sides.

Fresh egg masses can be found from September-December. They are about one inch long and have a grey mud-like covering which cracks over time as it dries out. The covering eventually flakes off revealing 30-50 brown eggs which resemble seeds set in 4-7 rows.

Spotted Lanternfly is an invasive insect that is an agricultural, ornamental, and nuisance pest. They feed on more than 70 different plant species, making it a serious economic threat to agricultural, especially orchards and vineyards.

Plant hosts for spotted lanternfly include grape, apple, plum, cherry, peach, nectarine, maple and walnut. They cause damage to plants by sucking out the sap and weakening the plant. Furthermore, they create “honeydew”, which increases the occurrence of sooty mold. Sooty mold blocks sunlight and inhibits photosynthesis for orchard trees and vineyard vines to produce fruit.

The favorite host plant of the spotted lanternfly is the tree-of-heaven. If you have this tree growing in your area, monitor for new infestations because of its preference for feeding on this species.

WVU Extension and the WV Department of Agriculture recommends removing all tree-of-heaven species from your property to help in controlling Spotted Lanternfly.

Early detection and prompt eradication efforts are crucial to controlling the spread of this invasive pest throughout West Virginia. Eradication efforts include physical trapping of the insect in all life stages, removal of tree-of-heaven and continued monitoring by the WV Department of Agriculture and citizens for new populations and egg masses.

Where did this tree of heaven come from? Tree-of-heaven is a rapidly growing deciduous tree native to China and Taiwan. It was first introduced into the United States in the Philadelphia area in the late 1700s.

The tree was initially valued as a unique, fast-growing ornamental shade tree with the ability to grow on a wide range of site conditions. However, by the early 1900s the tree began losing popularity due to its prolific root sprouting, and foul odor. It has spread across the United States from Maine to Florida and west to California occurring in 42 states.

Tree-of-heaven is typically a fairly small tree but can grow up to 80 feet tall. The most striking features are its very large leaves, which can measure up to two to four feet long. Tree-of-heaven has compound leaves, which means that each leaf is composed of many smaller leaflets.

A tree-of-heaven leaf can have 10 to 40 individual leaflets attached along a main stem. Leaflets have smooth edges and blunt teeth with raised glands at the base. The smooth leaflet margins distinguish tree-of-heaven from similar native trees with compound leaves, such as black walnut (Juglans nigra) and sumac (Rhus spp.), that have many small teeth, or serrations, along the edge of their leaflets.

Tree-of-heaven leaves and other parts release a strong, unpleasant odor that is often compared to rancid or burnt peanut butter. This tree’s bark is smooth and gray or brown, and lighter-colored vertical crevices appear on older stems. Tree-of-heaven produces clusters of winged fruits called samaras. Each samara consists of a flat, twisted wing with a round seed near its center.

Tree-of-heaven has some amazing characteristics to reproduce. Trees are prolific seed producers. Even a one-year-old tree can produce seeds, while a mature tree can produce more than 350,000 seeds per year.

In addition, they are exceptionally good at vegetative regeneration. Root sprouts and stump sprouts can grow vigorously and may grow 3 feet in height in a single season. Root systems of mature trees may extend as much as 90 feet from the parent tree. New sprouts can originate at nodes anywhere along the roots.

Due to its extensive root system and resprouting ability, tree-of-heaven is very difficult to control. Mechanical methods, such as cutting or mowing, are ineffective, as the tree responds by producing large numbers of stump sprouts and root suckers.

Basal bark herbicide treatments are the best control measure for tree-of-heaven. Treatment timing and following up the second year are critical to success. It is best to treat with an herbicide first, wait for symptoms to develop (approximately 30 days), and then cut.

Basal bark herbicide treatment is a control method in which an oil soluble herbicide is mixed with an oil carrier instead of water and applied directly to the bark of woody plants less than 6 inches in diameter.

A concentrated mixture of herbicide in oil is applied from the ground line to a height of 12 to 18 inches, completely around the stem of the tree. To maximize translocation to the roots, apply herbicides from mid- to late summer.

For basal bark sprays for tree-of-heaven, target the roots with systemic herbicides applied in mid- to late summer (July to onset of fall color) when the tree is moving carbohydrates to the roots. Herbicide applications made outside this late growing season window will only injure aboveground growth. Following treatment, repeated site monitoring for signs of regrowth is critical to prevent reinfestation.

In addition, herbicides applied to foliage or cuts on the stem are effective at controlling tree-of-heaven. Cut stump herbicide applications do not prevent root suckering and should not be utilized. There are many effective herbicides available for use on tree-of-heaven, including dicamba, glyphosate, imazapyr, metsulfuron methyl, and triclopyr.

Foliar herbicide sprays are used where tree height and distribution allow effective coverage without unacceptable contact with nearby desirable plants, applied in mid- to late growing season.

For dense or extensive infestations, treat initially with a foliar application to eliminate the small, low growth. Then follow up with a bark or hack-and-squirt application on the remaining larger stems. The initial foliar application will control most of the stems, while the follow-up stem treatment controls missed stems or those too tall for adequate coverage.

Well-established tree-of-heaven stands are only eliminated through repeated efforts and monitoring. Initial treatments often only reduce the root systems, making follow-up measures necessary. Persistence is the key to success.

Sawdust and sap from tree-of-heaven can cause skin irritation; be sure to wear personal protective equipment any time you plan to cut or otherwise injure tree-of-heaven.