New Insect Field Guide Available!

Most of you probably have seen the spiral-bound field guides produced by Iowa State University Extension. They have been very popular resources for farmers and ag professionals, and convenient for management in corn and soybean. Now there is a new full-size publication that is focused on insects available at the ISU Extension Online Store (CSI 0014) for $5! The guide can also be viewed online.

In January 2012, Iowa State University and the Iowa Soybean Association released a collaborative publication, Field Crop Insects, the latest in a series of practical and valuable reference tools for farmers. This publication is a comprehensive resource to help with identification and management of common corn and soybean pests. The 74-page publication is filled with vivid, full-color images and descriptions of insect pests and the damage they cause to soybean and corn. Management options are provided as well as Web addresses for access to more detailed insect control recommendations.

Getting the word out about rootworm resistance

I'm at the ISU Extension Ag Chem meeting in Ames today. My presentation will review the status of western corn rootworm resistance to Bt corn. There are several tactics farmers can use to delay resistance, and I will encourage people to implement in 2012.

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Entomologists are funny, just ask us!

Us entomologists don't really have that many jokes to tell. I still think "frass happens" is pretty good stuff. But this year at the ESA meeting in Reno, they had an insect-related limerick contest. There were many humorous and creative submissions - perhaps we are a funny society after all? The overall winner was Martha Lutz, who wrote a witty poem about fireflies:

Au Naturel Selection: Photinus meets Photuris
A firefly who was benighted
saw a light and became so excited–
he rushed to his fate
while selecting a mate:
lost his head, lost his heart, was de-lighted.

It's actually about an interaction between two firefly species. I encourage you to visit Bug Girl's blog that gives a bit more detail about insect mimicry and the deceptive nature of some fireflies.

Some female fireflies lure in males with false mating signals.  

Photo by J. E. Lloyd.

Award-winning YouTube Videos

For the last three years, the ESA (Entomological Society of America) conducts a "YouTube Your Entomology" contest for members called the Stinger Award. There are several categories (research, extension and open) to submit 3-minute videos about insects. I have been fortunate enough to have my videos win in 2009 and 2010. My first video was about my young niece, Chloe, and her love of monarchs. Last year, I made an extension video about using a sweep net in soybean. This year, I made an extension video about Japanese beetle management in corn and soybean. I also partnered up with Brian McCornack and Wendy Johnson at Kansas State University, to do a spoof video in the open category. We talked about how Speed Scouting, a sampling plan for soybean aphid, is going paperless with a web-based tool called SoyPod DSS. I ended up winning in both categories this year!

ESA Meeting in Reno

I'm attending the annual entomology meeting in Reno this week. I presented a talk on the Iowa pest survey I conducted in 2010. It was a great discussion on changes in soybean production since the arrival of soybean aphid.

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This is a call…for aphids in corn yield response data

Like the Foo Fighters song, “this is a call” for your assistance with field data. I am interested in strip trials with aphids in corn from 2011. Did you count aphids in corn and make foliar insecticide applications? If you are willing to share data, I am compiling a larger data set to help answer some basic biology and economic questions about aphids in corn. When do aphids start to build up and how high can the populations reach in corn? When were applications made and were previous applications made in the same year? How many aphids does it take to cause a yield response? Is this number different for drought-stressed field? What is the knockdown efficacy of currently labeled products? 

It got pretty bad for corn fields in NE and NW Iowa this year. I saw corn that was grey and covered with aphids, cast skins, and honeydew. Most of the heavy infestations were at the field edge, so scouts could have overestimated populations if they didn't sample throughout the field. This is a difficult task, given it was mid-August!

  Some fields had very heavy aphid infestations in corn this year. Aphids were colonizing the stalk, ears and leaves. Photo by Brian Lang.

All this information feeds into developing an economic threshold and sampling plan for future growing seasons. I would really appreciate hearing about your experiences with aphids in corn this summer. Please email (ewh@iastate.edu) or call (515.294.2847). Thank you!!

Can bugs be good and bad?

Building on my last blog topic, I am still amazed by how insects adapt to cold weather. Most insects seek refuge in the soil or under leaf litter, but some are adapted to finding cracks in rocky hillsides. Well, Iowa isn’t exactly the most diverse landscape and so many insects have to adapt. Unfortunately, that means some insects try to seek shelter in homes and other buildings. When insects are found inside, most people are very frustrated because they are a nuisance. But most people can keep these accidental invaders under control by sealing crevices around the house and removing them with a vacuum. 

There are a couple of fall invaders in Iowa that are especially annoying. But the multicolored Asian lady beetle (Fig. 1) probably tops the list. I think of it as a beneficial predator – a good bug – to have in field crops. The multicolored Asian lady beetle is one of the most abundant predators in corn and soybean. The larvae eat about 25 aphids a day and the adults can eat 15-65 aphids a day. Larvae feed for about two weeks and adults can live up to 90 days. That is a lot of aphids consumed in a lifetime. Egads!

Figure 1. Multicolored Asian lady beetle forewings range from yellow-orange to red with zero to 19 black spots, or may be black with red spots. Photo by Hedwig Storch, Wikipedia.

One myth about this beetle is that it was intentionally released to control soybean aphid. Not true! It was released in California around 1916, and was kept localized until the early 1980s. Since then, it has spread throughout the United States and Canada, and was confirmed in Iowa in 1994. So it was here before soybean aphid was confirmed in North America. 

Ok, it’s not all sunshine and lollipops. Here is where a good bug can do bad. The multicolored Asian lady beetle is native to China and Japan, and normally overwinters in the south-facing rocks in the mountains. They are especially attracted to prominent, isolated areas on the horizon, and light-colored objects. Adults like to mass on these structures and enter diapause. In areas that lack mountains and rocky hillsides (aka, Iowa), these beetles will attempt to enter human structures.

 Multicolored Asian lady beetles like to mass inside structures to survive the winter. Photo by Robert Koch.

In addition to invading homes, the adults can secrete a defensive chemical from the leg joints that is very offensive (e.g., wet, dead leaves). The chemical can cause stains and become an allergen. It can also taint wine grapes with a rancid peanut butter flavor.

But the biggest problem I have with multicolored Asian lady beetles is that they are too competitive! They are more aggressive and tend to displace our native lady beetles. The lady beetles eat aphids but will also eat other lady beetles. 

Overall, the multicolored Asian lady beetle is a good thing to see in field crops. Even though some may see it as a pest, I think the benefits outweigh the negatives. For more information, Robert Koch wrote an excellent review of multicolored Asian lady beetle biology.