Invasive Species: Tree of Heaven and Spotted Lanternfly

 SUMMARY: There is an interesting confluence of an invasive plant and insect species that may change our biosphere going forward. The Asian-origin tree species Tree of Heaven became a widespread invasive in the United States in the mid-1800s. An insect, the spotted lanternfly - first observd in the US in 2014 - prefers Tree of Heaven (TOH) as a host species, but also afflicts grape vines and fruit trees. It has been observed in Maynard as of 2026. As a means of dealing with both trees and insects, species-specific fungi and parasitic insects are being actively researched by the US Department of Agriculture (USDA).   

Adult Spotted Lanternfly on trunk
of a Tree of Heaven tree

Ailanthus altissima is the Latinate name for Tree of Heaven. The common name refers to its extraordinary growth rate. Ditto the Latinate name, as Ailanthus derives from an Asian word for sky-reaching-tree while altissima has Latin roots in altus, for high or highest.

As with many later-deemed invasive plant species, the initial introductions were deliberate. By the 1840s these trees were being sold commercially in the eastern United States, popular for city plantings because it thrives in poor soil and is resistant to drought and pollution. In California, immigrant Chinese workers at mines and railroads brought Tree of Heaven with them for its traditional medicinal purposes - the bark used to make an astringent tea.

Trees are either male or female. Both have flowers, but only the female trees create seed clusters. A mature tree can produce more than half a million seeds in a single season! These disperse by wind, and are rarely eaten by birds, mammals or insects. Deer will not eat the leaves nor nibble on the bark of saplings.

This species does not play well with others. As with garlic mustard, this plant produces chemicals which inhibit the growth of other plants, a trait that is referred to as being allelopathic. Combine that with prolific seed production, a growth rate much faster than any native tree, plus resistance to pollution and drought, and this tree is a major nuisance in urban and semi-urban environments unless vigorous combated.

Tree of Heaven smells bad. One disparaging nickname is 'stink tree.' Anyone who has tried to pull up seedlings or cut sprouts knows this tree has an offensive odor - sometimes described as having overtones of rancid peanut butter and/or cat urine. This test provides a mean to differentiate TOH from similarly leafed sumac, black walnut and other plants.   

Tree of Heaven is difficult to kill. Cutting results in new growth from the stumps plus a massive production of shoots from the surviving roots as far away as fifty feet from the original trunk. Systemic herbicides that kill roots (for example, triclopyr and glyphosate) currently provide the best chemical control. These can be sprayed on shoots, or holes can be drilled in the stumps of freshly cut trees and high concentration herbicide products applied directly. However, both application methods can cause collateral damage to nearby plants. The USDA is actively researching a fungus and several insect species as being specific to TOH, i.e., not causingt collateral damage to native plant species.  

Spotted Lanternfly showing forewing and underwing

Our second invasive, the spotted lanternfly (Lycorma delicatula), prefers TOH as a host species for the completion of its lifecycle, as they mate there in the early fall, lay eggs that will over-winter, and have wingless nymph stages which will feed on in late spring. Without TOH, nymph survival is lower and adult egg laying is less. Thus, removing the trees in the fall or spraying them with insecticides in late spring are important management stratagies. Adults are 1.0-1.5 inches long, with tan/grey forewings that have black spots and underwings that are partially bright red. The first documented appearance in the United States was in Pennsylvania in 2014. Since then it has spread to 17 states east of the Mississippi, with a financial impact on the grape, fruit and forestry industries already in excess of one billion dollars.

Given the very recent appearance in Maynard, it is unlikely that there will be large numbers of adults present this fall. However, if the infestation becomes bad in future years, large numbers can be expected to gather on TOH tree trunks, fruit trees and others. Insecticide sprays can be useful at these times.  

Several other means of controlling spotted lanternfly are being explored. A fungal pathogen that kills Tree of Heaven is being tested. Four species of fungi that kill spotted lanternfly are being evaluated as being species-specific, i.e., not killing native insects. These would require annual spraying of target food plants. In addition, three species of wasps native to China that are known to lay their eggs on spotted lanternfly egg masses. Again, care must be taken to confirm that bio-antagonists are specific to the target species. An example of succesful bio-control is the introduction of a parasitic wasp and a fly species to eastern Massachusetts about ten years ago that ended the infestation of winter moths.