Dr. Hodgson and O'Neal talk about the preharvest intervals for those soybean growers considering an insecticide late in the season.
We discuss the likelihood that aphid outbreaks will occur and when to spray aphid populations. Some agri-businesses are suggesting that aphids be sprayed when populations are lower than 250 aphids per plant. We discuss the value of such lower thresholds, as well as ways to detect other invasive insect pests of soybeans.
Aphid populations continue to increase in Iowa. We discuss their trajectory and when/if insecticides will be needed. Also, new publications from Iowa State University are available for the soybean aphid and the brown marmorated stink bug. To purchase the id guide for stink bugs or the new soybean aphid field guide visit the ISU extension publication store (www.extension.iastate.edu/store). To learn where the brown marmorated stink bug is in Iowa visit www.ncipmpipe.org.
The growing season is coming to an end and aphids still persist in some areas. We discuss how insecticides may cause problems with spider mites, especially with the use of pyrethroid-based insecticides. Also look for updates regarding bean leaf beetle threshold calculator in the ICM newsletter next week. Thanks to Mike McCarville.
It's hot! But we can still talk about aphids and other insect pests. It is a quiet week for soybean pests, but things are getting active in corn. We talk about what to look for when it comes to silk feeders. For more details about rootworms, a silk feeder and rootfeeder, look up Erin's recent factsheet. https://www.ent.iastate.edu/dept/faculty/hodgson/files/ul/CRW%20management%202012%20final.pdf.
At the end, Matt talks about a recent blog that summarizes his work on bees in soybean fields, http://www.agriculture.com/farm-management/conservation/bees-in-bes-qa-with-matt-oneal_556-ar32490.
Erin and Matt discuss the recent cool temperatures forecasted for the last week of July and the implications for soybean aphid populations in Iowa. We also discuss the recent emergence of bean leaf beetles and observations about the Brown Marmorated Stink Bug. For more info about the BMSB, visit http://apps.csi.iastate.edu/pipe/?c=entry&a=view&id=20
In this episode, Matt and Erin start by talking about foliar insecticide sprays for soybean aphid. Erin has a large efficacy evaluation program and screens many different products every year. She publishes the results in a Yellow Book (see previous editions here: http://www.ent.iastate.edu/soybeanresearch/content/extension). Then Matt talks a bit about corn rootworm biology and why that might be important in Iowa soybean.
Matt and Erin have a special guest on this podcast to help understand life cycle assessments. Dr. Kurt Rosentrater is an engineer and associate professor at Iowa State. Kurt explained the basics of conducting a life cycle assessment, including assumptions and resulting complications that come with this tool. They focused on a recent example looking at environmental impacts in four major crops. Here is the link to the paper so you can follow along with figures: http://www.ingentaconnect.com/content/iop/erl/2015/00000010/00000009/art094016. The assessment showed freshwater ecotoxicity impact in soybean increased 3-fold from 2002 to 2012. The authors claimed the insecticides used to control soybean aphid was an important factor. Corn, cotton and wheat did not have a significant increase of impact over the study duration. Learn more about Kurt's research and teaching program here: http://www.abe.iastate.edu/kurt-a-rosentrater-assistant-professor/.
Soybeans are going into the ground, and Matt and Erin have started a new podcasting season. They talk about early-season soybean pests, like black cutworm and bean leaf beetle, and the likelihood of seeing injury this year. Read more about the predicted cutting date for black cutworm here:
http://crops.extension.iastate.edu/cropnews/2016/05/black-cutworm-scouting-advisory-2016. They also spend some time highlighting some new people and research projects going on this summer. Finally, Matt talks about a recent publication that looks at the probability of breaking even with different inputs.
It's the first podcasting episode of 2017! Matt and Erin talk briefly about a few topics related to insecticides today. First, Erin recaps the findings of her insecticide resistance project from 2016. A field sprayed twice with a pyrethroid (bifenthrin) did not have efficacy against soybean aphid. She conducted an assay and discovered elevated resistance ratios for bifenthrin and lambda-cyhalothrin. Distinguishing insecticide group will become important for future growing seasons so farmers can prolong the efficacy of pyrethroids and organophosphates. Learn more about insecticide groups and resistance management at the IRAC website. Matt shared updates on pending EPA approvals of existing insecticides. Chlorpyrifos, an organophosphate, had an open comment period that closed January 17, 2017; read more about the health risk assessment for chlorpyrifos. In addition, the EPA has four public comment dockets open now regarding pollinator-only risk assessments for the neonicotinoid insecticides clothianidin, thiamethoxam, and dinotefuran.
Erin and Matt are speaking at the ISU Crop Advantage Series this month. Find locations and registration details here. Erin is also speaking on a resistance management panel at the 2017 Iowa Soybean Research Conference on February 8, 2017.
Watch an IRAC video on how insecticide resistance happens!