Tuesday, March 20, 2012

First black cutworm moth trapped in Iowa

About two weeks ago, we sent out a general request looking for cooperators to trap black cutworm moths in Iowa. We use the adult captures to help us predict larval cutting dates in corn. Last night, the first moth was captured in a trap in Muscatine County, Iowa. This is very early to see migratory moths moving up north. I am not sure what this means for spring populations, but last year had higher-than normal trap numbers. As a result, we saw more damaged corn and soybean during establishment. I will keep you updated on trap numbers for 2012 and predicted cutting dates later this spring. 

Black cutworm moth. Photo by Marlin E. Rice.

Check out these three new insect management articles!

Have you heard about a peer-reviewed extension publication called the Journal of Integrated Pest Management? It's an open-access journal (free for anyone to read and save files!). You can now access research-based management recommendations on all pests - not just insects and not just field crops. The Editors-in-Chief of JIPM are Marlin E. Rice of Pioneer Hi-Bred International (formerly with Iowa State University) and Kevin L. Steffey of Dow Agrosciences (formerly with the University of Illinois).

This new journal will offer a wide scope of peer-reviewed articles, including entomology, plant pathology and weeds. The intended readership for JIPM will be professionals who are engaged in any aspect of integrated pest management, especially those individuals working in crop protection, retailers, manufacturers and suppliers of pest management products, educators and pest control operators. The firs issue was released in October 2010.  and included articles about stalk borers and western bean cutworm. 

Three recently posted articles may be of particular interest to you. Click on the links to access pdf files:

1. Biology of the soybean aphid
2. Management of soybean aphid
3. Biology and management of bean leaf beetle and bean pod mottle virus

Alate (winged) soybean aphid and a few nymphs. Photo by Erin Hodgson

Thursday, March 15, 2012

Options for soybean aphid host plant resistance

Host plant resistance for soybean aphid is the newest management tool for farmers. In small plot evaluations of the Rag1 gene, there was a dramatic decrease in the seasonal accumulation of soybean aphid compared to susceptible varieties. The entomology department at Iowa State University recently released a new publication, Soybean aphid-resistant varieties for Iowa, that lists currently available soybean seed with resistance to soybean aphid. The list is intended to assist farmers wanting to adopt this new management tactic for soybean aphid.

The publication also contains Iowa State University recommendations for considering soybean aphid-resistant varieties. For more information on soybean aphid management consult: Soybean Aphid Management Field Guide 2nd edition. Additional information about insecticides is found in the most recent soybean aphid insecticide efficacy evaluation.

Small plot research shows the benefit of host plant resistance. Note susceptible plants (right) are covered with sooty mold that developed on aphid honeydew.

Host plant resistance for soybean aphid can dramatically decrease aphid growth over the summer, and often prevent the economic threshold from being reached. Ultimately, this new tool will help reduce production costs by reducing the number of foliar insecticides being applied to soybean.

Beetles, aphids and lacewings - oh my!

Yesterday I was sitting in my deck enjoying a nice evening. I noticed a few aphids landed on one of my dogs! Of course I got excited seeing the first winged aphid of the season (I know that only a few people in the world get a thrill from seeing aphids!). I have no idea what the species was, but I know it WASN'T soybean aphid. So I used my phone camera to take a few pics of the aphid and a few other insects flying around the yard. I noticed a multicolored Asian lady beetle, a few brown lacewings and a ton of flies. I did think it was interesting two of these insects are considered predatory as larvae and adults. I wonder if they were finding enough food? 

Tuesday, March 13, 2012

More bean leaf beetles predicted this summer

Iowa's warm winter and lack of moisture has generated a lot of talk about corn and soybean production lately. Some of the discussion is centered around insect survival and what a mild winter may mean for increased numbers this summer. I addressed some of these issues in a recent ICM News article with Laura Jesse, but specifically talked about bean leaf beetles in an article released today.

In general, overwintering bean leaf beetle adults are susceptible to cold temperatures and are more likely to survive a warm winter. Predicted mortality around the state is low compared to most years, ranging from 30-53%. But lack of insulating snow cover may actually increase mortality. With those factors in mind, I am estimating overwintering beetles may be out in greater numbers compared to the last few years. Early-planted fields should be scouted for adults, especially food-grade soybean.

Predicted overwintering mortality of bean leaf beetle based on accumulated subfreezing temperatures during the 2011-2012 winter.