The Iowa Department of Natural Resources (IDNR) Forestry Bureau in cooperation with Iowa State University Extension (ISUE) and Iowa Department of Agriculture (IDALS) State Entomologist Office have been following the United States Department of Agriculture Forest Service (USFS) protocol to monitor Iowa for signs of the emerald ash borer (EAB). The detection of EAB in Peru, IL in July 2007 places this insect only 85 miles away from Davenport, IA, which is of concern because of its proximity to Iowa and Interstate 80 linking the two states. Furthermore, the confirmation of EAB in Missouri and Wisconsin in 2008 is of great concern. According to recent sources, Iowa has an estimated 50 million rural ash trees (USFS 2006) and 30 million urban ash trees (USFS 2008).
A surveillance effort has been in place the past five years in Iowa to look for EAB. For 2004 and 2005, this activity consisted of visual surveys of urban ash trees (towns/cities with a population greater than 1000) in all 99 counties, visual inspection of ash saw logs at 43 sawmills, and ash nursery stock. Visual surveys in 2004 involved 2078 trees on 252 sites, and in 2005 involved 1318 trees on 238 sites.
During the 2006, 2007, 2008, and 2009 season, surveillance strategy shifted to the highest risk areas in the state, campgrounds. Sites were selected based on location near interstate highways, near tourism sites, and/or on the eastern border of Iowa. Up to 10 trees were examined in each campground for signs of EAB. The larger the campground and the greater the ash density, the more ash trees visually examined. In 2006, 417 ash trees were visually examined in 50 state and 10 county campgrounds. In 2007 EAB visual surveillance increased to 400 campgrounds (all federal, all state, all private and large campgrounds in 69 counties) involving 1102 trees. In 2008, 235 campgrounds in 55 counties were identified as high risk sites and 1,269 ash trees were inspected. In 2009, the same campgrounds were surveyed and 1,265 ash trees were inspected. No evidence of EAB was noted during visual surveillance in Iowa (2004 - 2008). A total of 235 campgrounds and all sawmills were surveyed during the 2009 detection year. The same 235 campgrounds and sawmills have been visually surveyed during 2010 and a total of 1,267 trees were inspected for signs and symptoms of EAB.
Sentinel trees in Iowa were created in one of two ways: girdling standing ash trees (4-13 inch DBH) or planting donated containerized ash trees (approximately 3 inch caliper). Sentinel trees were established by June 1 each season. In general, containerized trees were used for private campgrounds or in areas with few ash trees, while standing ash trees were used on federal, state or county properties. A tree was girdled by using a folding hand saw, making two cuts through the bark (4 - 6 inches apart), and then removing the bark with a drawknife between the cuts. Every effort was made to select standing ash either in the open or with exposure on two or three sides; trees were rejected as possible sentinel trees if they were within a forest stand.
In 2005, 48 sentinel trees (23 standing, 25 containers) on 12 sites were also used to monitor for EAB. In 2006, 68 sentinel trees (27 standing, 41 containers) were established on 18 sites; 10 were retained for evaluation in 2007. In 2007, 237 sentinel trees (190 standing, 47 container) were established on 57 sites. In 2008, 401 sentinel trees (272 standing, 129 containers). In 2009, 423 sentinel trees were bark peeled looking for EAB. EAB was not been detected in any sentinel of the sentinel trees. An additional 412 sentinel trees were established for the 2010 season and will be bark peeled in the fall.
USDA Experimental Traps
During 2010, 882 purple sticky traps are being utilized by USDA for detection efforts in Iowa. IDNR will be placing 450 of the purple sticky traps in Lee, Des Moines, Louisa, and Muscatine Counties. Traps are to be installed in May, and a midseason trap check is to be conducted approximately one month after placement, collecting suspect beetles, recoating panels with Tanglefoot, and reinstalling traps in the canopy. All traps will removed by the end of August 2010, and suspect insects collected, and traps discarded.
Community Management Plan
In 2009, IDNR conducted community tree inventories in 10 communities in Allamakee and Clayton counties and developed management plan suggestions for those communities. These management plans focus on overall urban forest health and proper management, as well as suggestions on how to manage the ash resource with the threat of EAB.
In 2010, IDNR received a USDA Forest Service grant that allows for community street inventories and management plans to be developed for 108 underserved communities (population under 5,000) in 12 eastern Iowa counties. These plans will focus on overall forest health of street trees, management cycles, risk tree mitigation, and suggestions on how to manage the ash tree populations. Regional meetings are being planned to answer questions from the 108 underserved communities that received management plans.