As Japanese beetles are spreading throughout Iowa and populations are increasing, more and more gardeners are dealing with these very hungry garden pests. Japanese beetle adults feed on a wide variety of plants. Iowa State University Extension specialists answer questions concerning these difficult to control pests. To have additional questions answered, contact the experts at hortline@iastate.edu or call 515-294-3108.

What are the Japanese beetle's favorite food plants?

Adult Japanese beetles have been documented to feed on the foliage, flowers and fruits of more than 300 different plants. Their top favorites are grape, cherry, apple, rose, raspberry and linden. A link to a list of the Japanese beetle's most- and least-favored woody plants can be found at the following website: www.ipm.iastate.edu/ipm/hortnews/2010/7-14/japanesebeetle.html

Can Japanese beetles be effectively controlled by using traps?

In a word, no. Several kinds of traps are available that use a floral scent and/or sex attractant to lure beetles into a net, jar or bag where the beetles can be contained till disposed of. In heavily-infested areas, traps may catch hundreds or thousands of beetles in the course of the summer. Unfortunately, this is a small percentage of the beetles in the area and makes no lasting impact on the beetle population or on the plant damage experienced.

The use of traps is not recommended. Research conducted in Kentucky and elsewhere found the traps do not control moderate to heavy infestations. The traps may attract more beetles than they catch and actually add more beetles to the yard than would occur otherwise.

In isolated locations far away from other Japanese beetle infestations, and in very lightly-infested areas, trapping may provide some benefit. Otherwise, traps will not make a difference.

Will treating my lawn for white grubs reduce the population of Japanese beetles on my plants next summer?

It would be nice if life could be that simple, but the relatively small area you can treat (compared to the grassy sites in the surrounding area) will not have any impact on the following year's adult population. Japanese beetle adults are very strong and capable fliers and may travel long distances from where they developed as larvae in fence rows, roadside ditches and other grass sites, to where they are feeding. You are likely to have beetles next summer whether you treat the grub stage in your lawn or not. Controlling one life stage does not preclude potential problems with the other.

This does not mean you should not treat the turfgrass. If desired, high value turf can be protected from the root-feeding larvae by treating the soil with a preventive insecticide in a timely fashion and according to label directions. Most of the available insecticides must be applied before mid-August to be effective as preventive treatments. Treating for grubs will protect the turfgrass. It will not prevent beetles from feeding in your landscape the following year.

What is the life cycle of the Japanese beetle?

In Iowa, adult beetles emerge in mid-June through July. Japanese beetles are similar to other Junebugs in appearance and 3/8 inch long and 1/4 inch wide. The head and thorax are shiny metallic green and the wing covers are coppery red. A distinguishing feature of the beetles is five tufts of white hairs on each side of the abdomen.

Japanese beetle larvae are typical white grubs. The larvae are in the soil from August until June where they feed on plant roots (especially turfgrass) and organic matter. The grubs are C-shaped and approximately 1.25 inches long when full grown.

Japanese beetles are defoliating my linden tree. Will they kill it?

Japanese beetles feed on more than 300 different plants. However, lindens are one of their favorites. Defoliation of well established, healthy lindens (and other trees) is usually not fatal. Defoliation is most harmful to recently planted trees (those planted in the last two to three years) and trees in poor health.

The foliage of recently planted and high-value trees can be protected with a soil-drench application of a systemic insecticide, such as imidacloprid (Bayer Advanced Tree and Shrub Insect Control and other products). To be effective, treatments must be made several weeks ahead of beetle emergence.

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AMES, Iowa – The Iowa Learning Farms' (ILF) June webinar, to be held Wednesday, July 20, at noon, will feature Emily Heaton, who will present "Giant Miscanthus and other perennial energy crops." The webinar is part of a series, hosted by ILF, held on the third Wednesday of each month. The webinars are held over the noon hour through Adobe Connect. All that is needed to participate is a computer with Internet access.

Emily Heaton is an assistant professor of agronomy at Iowa State University, focusing on biomass crop production and physiology. While pursuing her doctorate in crop sciences at the University of Illinois, she pioneered and led research comparing the biomass production of Miscanthus and switchgrass in the U.S., research that indicated Miscanthus could produce 250 percent more ethanol than corn, without requiring additional land. Heaton joined Iowa State from Ceres, a plant genetics company in California that specializes in biomass crop breeding for fuel. At Iowa State, Heaton focuses on best management practices for perennial energy crops, with particular emphasis on Miscanthus and switchgrass.

To connect to the webinar, go to: https://connect.extension.iastate.edu/ilf/. Heaton will be able to answer questions from webinar "attendees" via the Adobe Connect chat box. The ILF website homepage contains links for archived webinars from previous months: www.extension.iastate.edu/ilf.

Upcoming webinars include : ISU Agronomy professor Richard Cruse will discuss the report "Losing Ground" in August; Drake University Agricultural Law Center fellow Edward Cox will present information on the land tenure project with the Leopold Center for Sustainable Agriculture in September. Please contact ILF with other topic ideas for future webinar sessions.

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AMES, Iowa ? Iowa Learning Farms (ILF) is sponsoring a field day at the Iowa State University (ISU) Neely-Kinyon Research and Demonstration Farm near Greenfield, Adair County, on Wednesday, July 27, from 6 - 8 p.m. The field day will include a complimentary dinner, and information about strategies for no-till as well as information about incorporating perennial vegetation to enhance no-till. Attendees will be able to see and learn about Giant Miscanthus and other perennial energy crops. The event is free and the public is invited to attend.

Farmers and landowners interested in beginning no-till or who are experienced no-tillers can learn from the speakers at the field day. Greenfield area no-till farmer Randy Caviness will share his experiences from more than 20 years of no-till crop management. Jeremy Singer, research agronomist with the National Laboratory for Agriculture and the Environment, will answer questions about managing fall-seeded cover crops. The benefits of cover crops include enhancing no-till by reducing soil erosion and improving long-term soil tilth and water quality.

Also speaking are ISU Extension agricultural engineer Matt Helmers, who will discuss the potential of integrating perennial prairie strips with row crops to limit sediment and nutrient losses from crop acres. Emily Heaton, ISU assistant professor of agronomy, will showcase Giant Miscanthus plants that are being grown at the research farm. These perennial plants are being tested as an alternate source for biofuel energy production. ISU Extension agricultural engineer Mark Hanna will show farmers how to equip planters for successful no-till corn or soybean planting in high residue levels and will also offer farm energy and money-saving management tips.

Attendees are encouraged to bring their families to the field day to see the Conservation Station ? a mobile learning lab that teaches audiences of all ages about the importance of soil and water quality. The back of the Conservation Station houses a rainfall simulator, demonstrating the effects of rainfall on undisturbed soils with a variety of land covers, showing both surface water runoff as well as subsurface drainage. At the front is a learning center with displays and activities to learn about soil and water quality. Kids who attend the field day can become members of the "conservation pack" by participating in the Conservation Station's activities.

The ISU Neely-Kinyon Research and Demonstration Farm is located two miles south of Greenfield on Highway 25, then one-half mile east on 260th Street and a one-half mile north on Norfolk Avenue.

 

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The mosquitoes this summer have hit all-time highs and have been a real deterrent to being outside. Mosquito population trends for the summer have reached four times the number from last year. Visit the Iowa State University medical entomology lab mosquito surveillance website at http://mosquito.ent.iastate.edu/browse_county.php for more information.

"It is too late in the season for homeowner mosquito management actions to have much effect," said Laura Jesse, Plant and Insect Diagnostic clinician. "Eliminating all possible water sources - buckets, tires, bird baths, and other objects that hold water that the mosquitoes could use for their development may reduce the number produced on your property, but not those blowing in the wind from outside your property lines."

Floodwater mosquitoes (the most common biters) have no respect for property lines and easily can fly several miles from where they developed, according to Jesse. That's why the most effective mosquito management programs are those that involve an entire community or encompass a large area.

Personal protection remains the most practical way of contending with mosquitoes for the remainder of the year. Avoid the areas and times of day when mosquitoes are most active if you can, and wear long, heavy-knitted clothing. Apply mosquito repellents sparingly but thoroughly prior to going outside and wash thoroughly when you return inside.

The CDC suggests that you use any of several EPA-registered products that have been shown to provide reasonably long-lasting protection. For most people, a low-concentration product will be sufficient for short intervals out-of-doors. Those working outside longer can benefit from a higher concentration of active ingredient, or repeated applications as needed. EPA-registered products contain one of the following active ingredients: DEET, Picaridin, Oil of Lemon Eucalyptus or IR3535.

Consumer Reports magazine, July 2010, reviewed mosquito repellents and found that, "most of the tested products will do the job if you're going to be outside for only a couple of hours."

Also listen to a Consumer Reports podcast about the OFF Clip-On Repellent. Their conclusion was that the clip-on, fan-powered repellent did not work very well at keeping mosquitoes away from test subjects wearing the device in an enclosed cage of mosquitoes. Consumer Reports recommends that you choose a topical repellent for better results.

Giant numbers and giant mosquitoes
In addition to having an incredibly large number of mosquitoes in Iowa this year, extension entomologists also have had more questions and inquiries that start out, "I just saw the biggest mosquito of my life!"

"The very large mosquitoes that bite viciously are one of our 'usual' species found in Iowa," said Donald Lewis, extension entomologist. "However, this year is different in that the population seems to be larger than normal." The extra-large mosquitoes are in a genus called Psorophora. There is no customary common name for these mosquitoes, though some references use the term "gallinipper" or "gallinipper mosquito" for Psorophora mosquitoes.

Psorophora mosquitoes are a floodwater species. The females lay eggs on moist soil and the eggs hatch when covered with water from floods or temporary pools and impoundments. The larvae grow very quickly to the adult stage. Some of the Psorophora mosquito larvae are predacious; that is, they eat the larvae of other mosquitoes sharing the temporary pool. There can be several generations of Psorophora each summer depending on rainfall. In the fall of the year, the last eggs laid for the season remain dormant and wait for floods the following year. Some references claim the eggs can lay dormant for a long time and hatch years later.

Of the 14 species of Psorophora in North America, the one common in Iowa is Psorophora ciliata, a large mosquito with noticeably banded legs, pale stripes on the side of the dark thorax, and stiff, erect hairs along the legs. Females of Psorophora ciliata are vicious biters and prefer to feed on mammals. They will bite during both the day and night and are able to bite through heavy clothing.

"There is nothing special for the control of Psorophora mosquitoes," Lewis said. "The usual homeowner/gardener actions of eliminating breeding sites such as bird baths, plugged rain gutters and old tires may help reduce some kinds of mosquitoes, but not Psrophora that are breeding in flooded fields. Personal repellents remain the best defense against biting."

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