Posts tagged arborist

Getting ready for Japanese beetles

   I’ve been keeping a careful watch for Japanese beetles in my garden and enjoying my roses before the pesky beetle begins its annual invasion. The city of Cedar Rapids sent out the following today, (June 8, 2009) which made me wonder if Japanese beetles had already emerged. City arborist Daniel Gibbons, who wrote the article, assured me that he hadn’t seen any. Yet.

Japanese beetles

Japanese beetles

But, they will arrive, worse in some areas than others. If you haven’t seen this foreign invader yet, be grateful. Whether or not you have, read the following from Daniel Gibbons to learn more:

Japanese beetle has become one of the most destructive and frustrating pests for gardeners, farmers, and green industry professionals.  A transplant from Japan during the early 1900’s, Japanese beetle (Popillia japonica Newman) populations have enjoyed explosive growth across the East and Midwest.  Damage inflicted by various stages in the beetle’s life cycle can be severe to turf grasses, agricultural crops, and over 300 ornamental trees and landscape plants.  The USDA estimated in 2007 that control measures alone cost over $460 million.

Success of the non-native Japanese beetle can be primarily attributed to a lack of natural predators and a supportive climate and food source.  Although eradication is not feasible, successful management leading to reduced populations will minimize pest damage.  Those who succeed in managing Japanese beetle do so by gaining local cooperation, using an integrated approach to natural and chemical control, and by shrewdly selecting plant material when designing a garden or landscape.

Local cooperation is critical because of Japanese beetle mobility.  Despite the best efforts of one property owner, beetles from neighboring yards are usually a significant problem.  Success will increase if adjoining neighborhoods and property owners cooperate with sound management techniques.

Integrated Pest Management (IPM) is simply the use of multiple control techniques to reduce the comprehensive use of pesticides.  When properly used, IPM creates a healthy biotic environment in which populations of undesirable pests are reduced over time by the introduction of predatory elements, resistant plants, and targeted use of pesticides when necessary. 

Natural predators of Japanese beetle include microscopic nematodes (Heterorhabditis bacteriophora), naturally occurring soil bacteria (Bacillus thuringiensis), and the spores of Bacillus popillae (referred to as “Milky Spore”).  The success of these and other products can be effective, but depends on adherence to application and storage directions, climatic and soil conditions, and the presence of other pesticides or chemicals which may be harmful to these living organisms.  Products such as Milky Spore will become more effective over the span of several years when the bacterium has had time to establish.

Application of pesticides may be used to reduce heavy infestations, but should be performed by competent and trained applicators.  Some chemicals may only be used by licensed pesticide applicators.  Considerations in choosing insecticides to control Japanese beetle will include application method, seasonal timing, location, type of plant material being protected, and the presence of sensitive environment features such as waterways.  Assistance in choosing the latest formulation of pesticide for a particular site may be obtained from local garden shops or government extension agencies.

Finally, avoiding plants and trees that are susceptible to Japanese beetle is the best method to reduce the pest’s impact on a particular landscape or garden.  Keeping landscape plants healthy will also increase resistance.  The following trees are specifically targeted by Japanese beetle: Linden, Birch, Norway and Japanese maple, pin oak, beech and horse-chestnut.  Trees that show resistance to the beetle include hickory, red maple, tulip poplar, dogwood, northern red oak, pine, spruce, arborvitae and hemlock.  Resistant herbaceous plant groups include: Columbine, ageratum, coreopsis, coral-bells, showy sedum, hosta, and forget-me-not.  Herbaceous plants to avoid in areas where beetle populations are high include: rose, hibiscus, evening primrose, clematis, sunflower, peony, zinnia, asparagus and morning-glory.

Despite recent challenges with Japanese beetle, thoughtful management can reduce the impact to community gardens and landscapes.  Education, cooperation and savvy IPM practices will also reduce the impact on our pocketbooks, while promoting a healthy and vibrant growing season.

More information on Japanese beetle may be obtained through the following online sources: “Managing the Japanese Beetle: A Homeowner’s Handbook”

Iowa State University – Iowa Insect Information Notes

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Invasive species alert!

Callery pear photo by New Invaders Watch List
Callery pear photo by New Invaders Watch List


 Cedar Rapids City Arborist Daniel Gibbons wants residents to be aware of an invasive species that could become a problem soon in Iowa. The ornamental Callery pear is a popular urban landscape tree, valued for its white flowers.  But Gibbons, who served as horticulturist in Columbia, Mo., and has held his Cedar Rapids post since January, warned that as the trees age, hybridizing starts. The wild seedlings, which produce thorns and have weak branches, can grow in the sun, shade, or anywhere and overtake prairies and other native areas. Birds that eat the berries spread the seeds.

    While Gibbons has not heard of the wild version growing in this area yet, he noted that education is important. “In order for it not to happen, the word needs to get out,” he said. “Education may save us.”

      Here is more on this invasive species, from the Cedar Rapids Public Works Department:

 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 home owners 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.

 Pictures are available at under City News.  Click on the Invasive Species Alert link to view the PDF file.








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Salt, de-icers and trees

The following is from the International Society of Arboriculture. The group’s Public and Industry Relations Manager, Sonia Garth, encouraged readers to also check out their Web site at for more information.


     When winter snow and ice begin to fall, so does the salt, on driveways, sidewalks, and streets to aid in melting away potential hazards. Keeping our surroundings safe during the winter months is important, but salt can be a serious threat to our trees, when used without caution.

     “Excessive exposure to salt can cause widespread damage to your trees, leading to permanent decline and sometimes death,” said Jim Skiera, Executive Director of the ISA. “The problem with salt damage is that it might not show up on your trees until summer, when deicing salt is the last culprit you would suspect.” 

     To minimize the damage done to trees by deicing salts, Certified Arborists at ISA offer the following tips:

1. Use less salt. Mix deicing salt with abrasives such as sand, cinders, and ash, or use alternatives such as calcium magnesium acetate and calcium chloride.

2. Protect your trees from salt trucks on the street. If possible, set up barriers between the street and your trees to keep salt spray from hitting tree trunks.

3. Plant salt-resistant trees. Trees such as the sycamore maple, white spruce, willow, and birch tend to be more salt-resistant than other species. How well they fare varies from climate to climate across the country.

4. Improve soil drainage. Add organic matter to your soil to help filter salt deposits.

You can also keep your trees healthy by taking care of their basic needs. Other tips that will help combat the damage done by deicing salt include:

·        Irrigate to flush the salts from the soils in spring

·        Mulch sufficiently to reduce water loss.

·        Control pest infestations and destructive tree diseases.

     If you feel your trees may be susceptible to salt damage, contact a local ISA Certified Arborist in your area.

The International Society of Arboriculture (ISA), headquartered in Champaign, Ill., is a nonprofit organization supporting tree care research and education around the world. As part of ISA’s dedication to the care and preservation of shade and ornamental trees, it offers the only internationally-recognized certification program in the industry. For more information on ISA and Certified Arborists, visit


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