Insects
Emerald Ash Borer (EAB)
Spotted Lanternfly
The Iowa Department of Agriculture and Land Stewardship asks Iowans to be on the lookout for spotted lanternfly insects. The colorful but invasive and destructive insect is native to China, India, and Vietnam, and was accidentally introduced into Pennsylvania in 2014. It has since been confirmed in eleven states and often spreads by the movement of infested material or items containing spotted lanternfly egg masses. If allowed to spread further in the United States, this pest could seriously impact the country’s grape, orchard, nursery, and logging industries.
Spotted lanternfly adults and nymphs frequently gather in large numbers on host plants. They are easiest to spot at dusk or at night as they migrate up and down the trunk of the plant. During the day, they tend to cluster near the base of the plant if there is adequate cover or in the canopy, making them more difficult to see.
More information on this invasive insect is available on the Iowa Department of Natural Resource's website: https://www.iowadnr.gov/Conservation/Forestry/Forest-Health/Spotted-Lanternfly
If you think you have found a spotted lanternfly, please call the Entomology and Plant Science Bureau at 515-725-1470 or e-mail Entomology@IowaAgriculture.gov. You may also contact your local county Iowa State University Extension Office.
Spongy Moth:" Lymantria dispar"
The Spongy Moth is an imported pest that has devastated parts of the Eastern United States. There have been some sightings in Iowa, and the areas have been aggressively treated. A good web site for more information is Iowa State University.
Asian Long Horned Beetle
The Asian Long-horned Beetle, which is from China has been found as close as Chicago, Ill. Believed to have hitchhiked in wooden packing crates from China. It is very expensive to eradicate as the only way is to remove all infected trees and the healthy trees immediately surrounding the affected area. A very good website on this subject is the National Forest Service.
Japanese Beetle: "Popillia japonica Newman"
The Japanese beetle (Popillia japonica Newman) is a highly destructive plant pest of foreign origin. It was first found in the United States in a nursery in southern New Jersey nearly 80 years ago. In its native Japan, where the beetle's natural enemies keep its populations in check, this insect is not a serious plant pest.
In the United States, however, the beetle entered without its natural enemies and found a favorable climate and an abundant food supply. By 1972, beetle infestations had been reported in 22 States east of the Mississippi River and also in Iowa and Missouri. Since then, the pest has continued to disperse south and west. Isolated infestations have been found in Wisconsin, Oregon, and California. Without its natural checks and balances, the Japanese beetle has become a serious plant pest and a threat to American agriculture.
To control the Japanese beetle, an Integrated Pest Management (IPM) program is needed. Several potential tactics are available, including chemical and biological controls, habitat modification and trapping.
Systemic insecticides are effective, but need to be applied in mid to late May at the latest in order to protect plant material when the beetles emerge in June. In addition, lawn treatments to control grubs should be a part of the management program. Canopy sprays are not as effective as this two-pronged approach.
Mechanical traps can help to reduce beetle populations; however, you must remember that the traps will draw beetles to your property. Therefore, place traps at the borders of your property, away from plants the beetles may damage.
The Japanese beetle can be a destructive pest of trees, plants, and turf. It is important to understand that an IPM program will not eliminate all Japanese beetles from your property but it can help you reduce the damage inflicted by this pest.
Diseases
There are several diseases that affect the urban canopy in Cedar Rapids. Most are primarily aesthetic issues that don't affect tree health. The two primary diseases of concern are Oak Wilt and Dutch Elm diseases. Bur Oak Blight is also a growing concern. The current plan for managing these issues is the following:
How to Identify and Manage Dutch Elm Disease
http://na.fs.fed.us/spfo/pubs/howtos/ht_ded/ht_ded.htm
Oak Wilt - Identification and Management
https://store.extension.iastate.edu/Product/sul15-pdf
Bur Oak Blight Pest Alert
http://na.fs.fed.us/pubs/palerts/bur_oak_blight/bob_print.pdf
Invasive Species
Ornamental (Callery) Pear
The introduction of exotic plant and tree species for the purpose of aesthetic gardens or utilitarian roles has been practiced within the fields of horticulture and forestry since ancient times. Our tendency to become dissatisfied with native flora all too often cultivates a desire to expand our landscape pallet to non-native varieties and cultivars. Such new specimens can produce vivid floral or textural displays, offering an arboretum or landscape renewed appeal.
Unfortunately, the cost of promoting newly discovered species that are out of place in our native ecosystem is rarely known until years after introduction. Much of the time there are minimal impacts to the native ecosystem from well-contained non-native landscapes. Occasionally however, a plant or tree can escape and pose enormous consequences to native plant communities.
Pyrus calleryana, is one such exotic species that has “escaped”. Ornamental (Callery) pear trees have been prized for their tidy form and magnificent spring display of snow white flowers. Although now known to be weak-wooded and prone to storm damage, Callery pear cultivars such as ‘Redspire’, ‘Bradford’, ‘Capital’, ‘Cleveland Select’, and others are foundational to many landscapes because of their sure establishment and nearly pest-free acclaim.
Although earlier thought to be sterile and unable to reproduce, wild hybrids are now sprouting up across the country where landscape pear plantings have matured. These new pear hybrids are not only thorny, but also have retained the weak branching structure of the parent cultivars. Hybrids from nursery-produced trees are also extremely vigorous and seem to tolerate numerous site conditions, eventually producing a thorn-filled stand of trees too thick for native regeneration. This spread may prove to be one of the most serious problems to date for land managers and homeowners alike.
Within our neighboring state of Missouri, Columbia Park Natural Resource Supervisor Brett O’Brien successfully partnered with the Missouri Department of Conservation and the Missouri Community Forestry Council to form an educational program called, “Stop the Spread!” In 2002, the Columbia Parks Department began noticing wild pear trees growing in a natural area. Within 6 years, thorny hybrid pear trees are now abundant and increasing within Columbia utility right-of-ways, natural areas, and even well-maintained park landscapes.
According to an article by Theresa Culley and Nicole Hardiman in Bioscience (December 2007 / Vol. 57 No. 11), Callery pear cultivars are now listed by 6 eastern states as invasive, with more to come. Culley/Hardiman note that pear hybrids spread rapidly within restored prairie wetlands and are capable of producing “impenetrable” thorny thickets.
As ornamental pear populations increase from landscape plantings within our region, the danger for cross-pollination and the production of wild pear hybrids will increase. The importance of developing awareness to this problem and reduction of market demand for ornamental pear trees is critical. Homeowners, developers, nursery growers, and municipal forestry departments share the responsibility to promote the use of alternative species as substitutes for the Callery pear. Without such cooperation, Central Iowa could soon face the costly and ecologically devastating effects of hybrid pear colonization now being realized elsewhere.
