It's alive!!

It's been a long time since my last post! But it's ALIVE again...

This cool and very wet spring had impacted planting progress and insect development. So the usual field crop suspects haven't started to show up and are especially behind the 2012 emergence schedule. Some of the questions popping up lately have been with soil-dwelling insects and saturated soils. My general thought on this is that eggs can survive in wet soil, but larvae can't for too long. So if they are small and not very mobile (like corn rootworm larvae), they will probably suffocate. Good news if you like to grow corn!

Cool wet growing conditions in May and June do favor slugs. I wrote up a recent ICM News article today about managing these early-season beasts. Unfortunately, no-till or minimal tillage practices are conducive to slug populations.

Slugs can destroy corn and soybean seedlings. Photo by Brian Lang, ISU.

I will try to post more regular updates about other emerging pest activity. Send some of your observations and pictures my way. Thanks for your continued interest in my blog!

Live brown marmorated stink bugs in Iowa

The first specimen of brown marmorated stink bug (BMSB)  in Iowa was confirmed last February in Cedar Rapids. Since then, several other dead BMSB have been confirmed by our ISU Insect Diagnostician, Laura Jesse. Recently, there have been some live detections near Davenport and Bettendorf, Iowa.

Brown marmorated stink bugs have a marbled coloration, and white-banded antennae. Photo by Laura Jesse, ISU. 

These stink bugs are established along the east coast for about a decade. They have been migrating westward in the U.S. When they invade a new area, they are typically considered an urban pest. They attempt to overwinter in human structures similar to boxelder bugs and multicolored Asian lady beetle. But they eventually become a pest of fruit and field crops. Adults and nymphs will probe fruit and leaves, causing necrotic spots. BMSB feeding can severely deform soybean, and cause "stay green" along soybean field edges. 

Stink bug feeding during the seed fill stage can cause deformation, shrinkage and discoloration in soybean. Photo by Galen Dively, University of Maryland. 

At this time, we don't know if BMSB is established in Iowa, or if a few individuals have hitchhiked here. If you suspect BMSB around your home or buildings, submit samples to the ISU Plant and Insect Diagnostic Clinic. Instructions for submitting samples can be found here.

Can insects scream?

Someone recently asked me if aphids make sounds when approached by predators. I thought it was a really interesting question, and not just because it was about my favorite insect! I am not aware of aphids making noise when threatened, although they do have other defense mechanisms I may share at a later time. But it did get me thinking about insects that can make noise and how sound is generated a few different ways.

Cicadas probably come to mind as a well-known noise maker. The males can produce sound, sometimes up to 120 decibels - technically loud enough to cause hearing loss in humans! They have a thin membrane on the outer abdominal wall, called a tymbal. As the abdominal muscles contract and relax, it causes the tymbal to click. Cicadas rapidly vibrate the membrane and the sound amplifies in enlarged air chambers in the abdomen. Each species would have it's own "song" to attract females.

Periodical cicada, www.ipmimages.org.

Most insects stridulate, or rub body parts together, to make noise. In most cases, the males stridulate to attract mates. Crickets and katydids have serrated teeth on the edges of their wings that form comb-like structures. They drag the combs against each other to create sound. But they rub the wings so fast that it just sounds like a chirp. Crickets have four types of chirps: a loud calling song to attract females, a quiet courting song when a female is near, an aggressive song to repel other males, and a brief song after mating. Crickets chirp at different rates depending on the species and temperature. The relationship of cricket chirping is also called Dolbear's Law.

Field crickets use their wings to create sound. Photo by David Cappaert, Michigan State University, www.ipmimages.org. 

Other insects, like grasshoppers and beetles, scrape their legs to make sound. Grasshoppers have stiff peg-like spines on the hind legs that they rub against their wings. Some long-horned grasshoppers will rub their front legs together for their species-specific "songs."

Striped slant-face grasshopper with stiff spines on the hind leg used for stridulation. Photo by Gerry Fauske, North Dakota State University. 

Some insects use their heads or even their mouthparts to make clicking noises. But perhaps the weirdest noise-making insect I discovered was the tiny water boatman. This aquatic insect can "sing" at 99 decibels by rubbing its penis against his abdomen. Don't ask me how scientists thought of researching this idea or how they collected the data.

The tiny water boatman can generate a very loud sound, www.bbc.co.uk. 

I found a few nice websites that have audio clips of insects making noise. Enjoy!

Insect Sounds, www.naturesongs.com/insects.html

Bug Bytes, www.ars.usda.gov/sp2userfiles/person/3559/soundlibrary.html

Songs of Insects, www.musicofnature.org/songsofinsects/index.html

Harvest begins!

In 2012, we worked at several ISU Research Farms, including: Northwest, Northeast, Southeast, Southwest, and Johnson Farms. We were working mostly in soybean but also had several corn trials this year. Plots are drying down quickly and we are preparing for the last step in our summer research - harvest! Usually it goes pretty slow for us because we have to stop often to weigh grain in every plot. Some of the farms have automatic scales on the combine - otherwise we have to weigh grain by hand. 

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:

http://www.rachelcarson.org/

http://en.wikipedia.org/wiki/Rachel_Carson

http://www.pophistorydig.com/?p=11132

http://museum.msu.edu/?q=node/687

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.

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.