Wednesday, August 29, 2012

Silent Spring: 50 years of raised environmental awareness

Today I am reminded of one the most important books I've ever read. During my first year of grad school, I was encouraged to read Silent Spring by Rachel Carson. She was an environmentalist, joining the US Bureau of Fisheries in 1932. I am sure that wasn't easy thing for a woman to do back then! Rachel became a full-time writer in 1949. She wrote several environmentally-themed books about the ocean, but became interested in soil-dwelling animals, too. As Rachel was battling breast cancer, she published Silent Spring in 1962. 

Rachel Carson, 1907-1964

Silent Spring was one of the first books to address some of the negative effects pesticides can have on animals, including humans. She often argued for more "look before we leap" caution to synthetic pesticides. One of the first popular pesticides, DDT, was manufactured by the Swiss in 1939. DDT was used by many around the world, including the US Army to control malaria, typhus, and dengue fever during WWII. 

DDT trucks were common to see on the streets in the 1950s. Sometimes kids would run after the trucks to get dusted. 

To show how harmless DDT dust was to humans, advertisements like this were popular. Model Kay Heffernon with a soda and hot dog on Jones Beach, NY 1948. Photo by George Silk, LIFE photos. 

DDT was popular for home use as well to kill nuisance pests. 

At the same time of increasing popularity of synthetic pesticides, Rachel was noticing a decline in bird populations. She called pesticide overuse as a "silencing of the birds." In Silent Spring, she outlined how biomagnification concentrated chemicals through the food chain. Although she reviews many case studies in her book, her example of robin decline at Michigan State University was particularly interesting. In the mid 1950s, ornithologist George Wallace discovered dead and dying robins on campus; tests confirmed elevated levels of DDT. He later showed DDT used to control Dutch Elm Disease was takeng up by earthworms that were toxic food for many birds. 

Another example of DDT biomagnification was in the Bald Eagle. By the early 1960s, only about 400 breeding pairs were in the lower 48 states. One suspected cause of decline was egg shell thinning and sterility from DDT. In 1967, Bald Eagles were placed on the Endangered Species List. The US banned DDT in 1972 and the number of breeding pairs has dramatically increased 20-fold. In 2007, the Bald Eagle and other bird species were removed from the Endangered Species List.

Her books and other publications got mixed reviews from scientists and industry. She testified before congress and called for a "pesticide commission" to help protect human health and the environment. Of the 12 pesticides she mentioned in her book, 8 are now banned and 3 are severely restricted. Rachel raised awareness for the environment and the need for regulation; and in 1970 the EPA was created. She revived many awards for her efforts, including the Presidential Medal of Freedom after her death. Although I do think pesticides have a place for pest control in order for food production and human health, I do agree with Rachel that we should them in more cautiously and with purpose. For more information about Rachel Carson, visit these links:

Monday, August 20, 2012

Updated bean leaf beetle thresholds

Summer is winding down fast, but some areas in Iowa still have respectable numbers of bean leaf beetle. The second generation is coming out and could cause direct injury to soybean pods. If your beans are still developing, it might be a good time to go out and take some sweeps.

 Bean leaf beetles can be confused with southern corn rootworm and other beetles. Look for four dark spots on the forewings, and a dark triangle behind the "neck." Photo by Marlin E. Rice. 

Overwintering and first generation bean leaf beetles rarely cause direct economic damage to soybean in Iowa; plants compensate for defoliation in many ways. But they can transmit bean pod mottle virus that can impact the market value of food grade soybean. Bean leaf beetle can cause direct injury to pods during the seed fill stage depending on when the second generation emerges. 

Bean leaf beetles can eat about 0.2 pods per day. Note they don't eat all the way through the pod, like grasshoppers can. Photo by Mark Licht, ISU Extension. 

Last year I had several questions about treatment thresholds for bean leaf beetle given our higher market values. With the help of ISU entomology grad student, Mike McCarville, we created a dynamic threshold calculator. It's a downloadable Excel file where you plug in your market value and control costs. Visit this ICM News article and scroll to the bottom for the link the calculator. To learn more about bean leaf beetle biology and management, click here.

Thursday, August 16, 2012

2012 Insect Field Clinic a success

Yesterday, I hosted an all-day clinic for insects at FEEL just west of Ames. I don't think there has been an ISU insect-focused field day in over 15 years. I planned a combination of inside and outside presentations and some hands-on demonstrations. There were even 3 guys from Hawaii attending the meeting! I thought you might like to see some photos of the clinic.

Bob Wright, Professor of Entomology at the University of Nebraska-Lincoln, came out and helped with a few of the classes. Photo by Adam Sission, ISU IPM Program.

We reviewed identification and management of common corn and soybean pests. Much of the conversation was around corn rootworm. Photo by Adam Sission, ISU IPM Program.

Everyone got a chance to use Bt tissue testing kits for corn rootworm. These tests are an important first step when visiting potential problem fields in Iowa.  Photo by Adam Sission, ISU IPM Program.

The guys from Hawaii really enjoyed their trip to Iowa. They learned a lot about intensive row crop agriculture!  Photo by Adam Sission, ISU IPM Program.

Friday, August 10, 2012

Big spray day at Nashua

This morning, we sprayed foliar insecticides at the Northeast Research Farm near Nashua, Iowa. This is the nation's largest soybean aphid efficacy evaluation, and it's been building ever since it started in 2005. This year, we had 35 treatments at Nashua and 25 treatments at the Northwest Research Farm near Sutherland. We also have a smaller evaluation for Japanese beetle near Ames.

This year, our soybean aphid counts have been almost non-existent. But we are trying to make lemonade out of our research trials. We've been monitoring for spider mites as well, and will have some updated information on efficacy summaries after harvest. We publish all of our soybean pest evaluations in a Yellow Book and post them online. You can find 2005-2011 Yellow Books on our soybean aphid website.

I thought you might like to see our spray crew in action. Enjoy!

Safety lab is very conscientious about PPE!

 We use a backpack sprayer with a 6-row boom to cover our plots. It takes two people to get the job done. 

It took about 4 hours to get all the plots treated this year. It was great weather to spray this year!

Thursday, August 9, 2012

Finding an orange bug in corn?

This week, I had a couple of questions about "orange bugs in corn." I scoured through my reference materials and also on the web. I didn't see anything that quite matched up to the descriptions over the phone. But someone actually sent a picture to me and that really helped. It was none other than the very common boxelder bug! Donald Lewis, ISU Horticulture Entomologist, recently reported exceptionally high numbers of boxelder bugs in Iowa this year. Our warm winter and spring was ideal for boxelder bugs to survive and then boom in numbers.

Boxelder bug adult. Note the red-orange wing margins and red eyes. Photo by Joseph Berger,

Most people can easily recognize boxelder bug adults in urban areas, particularly on maple and ash trees. But the nymphs are bright orange or red, and can be confused with other insects.

Boxelder bug nymphs sort of look like big, red aphids. Eventually the nymphs will develop dark wing pads. Photo by Whitney Cranshaw,

Boxelder bug nymphs and adults prefer to feed on boxelder seed pods, but they have been found on many different plants this year. They rarely damage ornamental trees and are not a concern to field crops. Sometimes the adults can become nuisance pests in the fall when they try to overwinter in human structures. I suspect they will be an issue this fall based on our summer numbers.

 Here is a mixture of boxelder bug life stages. Photo by William M. Ciesla, Forest Health Management,