The Current Corner is designed to inform residents of the latest information regarding our urban forest. Insects, diseases and other issues affecting the health of Wilmette ’s parkway tree population will be updated as needed in the current corner. Stay tuned for the latest news.
Get ready to plug your ears, Wilmette ! The 17 year cicada is set to emerge in the Chicagoland area this spring, likely in late May to early June. For those of you who are from this area, you will remember the less than welcomed sound periodical cicadas can make. Though large, their “bark is worse than their bite” as they pose no threat to you or your pets. Females lay eggs on the outer smaller branches of some trees (including oaks and maples) which can cause some tip dieback, but this damage is minor and the trees will recover.
A few cicadas “singing their song” is not that noticeable, but tens of thousands of cicadas singing in unison is quite loud. Males are the only ones that produce this song, as ridged membranes vibrate producing the sound that attracts females for mating. This singing can go on for up to 4 weeks. Females lay eggs on tree branches and these eggs hatch into tiny nymphs within a couple weeks. The nymphs fall to the ground from the trees and subsequently bore into the soil to begin feeding on roots. The nymphs go through 5 life stages sustaining itself through root feeding, which research has shown has little effect on plant health. The most feeding is done towards the end of the nymph stage, when it’s at its largest size (about 3/4”), as it gets ready to emerge from the soil. The nymphs then crawl up vegetation before molting into adults.
Without the sighting of the Asian Longhorned Beetle (ALB) for over three years in the Chicagoland area, the Illinois Department of Agriculture lifted the last quarantine that had been applied to an area around Oz Park where three (3) infested trees had been found in 2003. Authorities had previously lifted a similar quarantine in 2005 that encompassed the Ravenswood neighborhood. Trees and firewood are now allowed to be moved freely into and out of these areas. City of Chicago officials will continue to monitor those previously affected areas for any signs or symptoms associated with the ALB.
The Asian Longhorned Beetle (ALB) is native to China and prefers Maple, Horsechestnut, Poplar, Willow , Elm, Birch, Ash, Hackberry and Mimosa (silk tree) tree species. The ALB is an insect pest that can cause serious tree damage and death as larvae create winding galleries in a tree’s water (xylem) and food (phloem) conducting vessels.
The ALB was first discovered in the Ravenswood area ( Chicago ) in 1998. In order to control the infestation, approximately 1,500 trees were cut down and two (2) quarantine areas, covering most of Chicago ’s north side, were established. Once quarantine areas were established, numerous ‘Sentinel’ trees, attack-and-kill system, were inoculated with pesticides.
In addition to the Ravenswood area, four (4) quarantine areas were established in the Village of Addison and Village of Summit in 1998. In 1998, 35 infested trees were found in the Village of Addison . Since 1998, similar steps as those in Ravenswood have been taken to control the ALB. Little activity has been reported over the past six (6) years in the Village of Addison and Summit .
In March of 2004, the United States Department of Agriculture’s Animal and Plant Health Inspection Service has amended ALB quarantine areas. Through intensive surveys and inspections, quarantines encompassing Addison , in DuPage County and the Village of Summit , in Cook County , and areas of Chicago no longer display evidence of ALB infestation and are removed from the quarantined region of Illinois . Currently, areas of New York and New Jersey are the only areas under quarantine for the ALB.
For more information about the Asian longhorned beetle, please visit the USDA website http://www.aphis.usda.gov/ppq/ep/alb/.
For more information regarding these of the Current Corner topics, please don’t hesitate to contact the Village’s Forestry Division at 847-853-7600 or 853-7587.
Wilmette Public Works