Soybean Pest Podcast
In this episode, Matt and Erin talk about managing twospotted spider mites in soybean. Considering other pests is important, given the non-target effects with an application. This is particularly true if soybean aphid is in the field because of recent reports of pyrethroid resistance. They discuss options, including using miticides to suppress mite populations. Implications of pest ecology and economics plays a part in managing soybean pests.
Twospotted spider mites. Photo by Frank Peairs; www.ipmimages.org.
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!
Matt and Erin wrap up a few loose ends before the holiday week. First, Matt shares DowAgroSciences sulfoxaflor insecticide got a renewed registration. This insecticide targets fluid-feeding insects and was an option for soybean aphid before it was canceled in 2015. Now, sulfoxaflor can be used in a number of crops, but not for corn or soybean; cotton and sorghum have emergency labels in some U.S. states. Over the weekend, a soybean aphid Biotype-2 colony died due to a bad compressor in a growth chamber. Aphids don't tend to do well in temperatures over 100 degrees, and these ladies got cooked. Our labs host all four soybean aphid biotypes plus a few other aphid colonies. Colony management is really important and the maintenance is ongoing to keep plants and aphids healthy. Iowa State University features a 3MT (Three-minute thesis) oral competition this week. Three people featured insect-related presentations (a long video of all the speakers can be found here).
Upcoming extension events:
ICM Conference (30 Nov, 1 Dec) in Ames
Crop Advantage Series (January 2017) in Iowa
CCA Online Review Course, (on demand)
In this episode, Matt and Erin interview the 2016 Gunderson Memorial Seminar speaker, Dr. Ric Bessin. Ric is a professor and extension entomologist at the University of Kentucky. His areas of extension and research interests range from row crops to specialty crops, and has a focus on IPM. Their conversation starts off talking about agriculture in Kentucky compared to Iowa.
He also shares observations about early season pests, like wireworms, and moves to brown marmorated stink bug, an invasive species causing havoc in Kentucky. Ric was also a Peace Corps volunteer before graduate school, and where he spent time beekeeping. He shares an interesting story about using bees to help with pain management.
Due to technical difficulty, this is a second take at the podcast today. Matt and Erin start by sharing highlights from the recent International Congress of Entomology (ICE) meeting in Orlando last week. Erin talks about pest resistance issues for corn rootworm and western bean cutworm. Matt summarizes some work on rapid resistance development in agro-ecology systems. Fall nuisance invaders were also briefly discussed, including minute pirate bugs, boxelder bugs and lady beetles. Matt got excited by a recent aphid find on ISU campus this week - aphids and parasitized aphids were on collected from buckthorn. They don't understand the implications for these finds yet, but it is certainly not a common find. Lastly, Matt and Erin are speaking at the upcoming ICM Conference in Ames. Registration details will be posted soon.
Minute pirate bug adult feeding on white fly nymphs. Photo at https://en.wikipedia.org/wiki/Anthocoridae.
Today, Matt and Erin talk about noteworthy news items related to field crop pest management. But first, they talk about upcoming meetings they plan to attend. Both are attending the ICE (International Congress of Entomology) meeting in Orlando next week. And both plan on speaking at the annual ISU Integrated Crop Management Conference in Ames (Nov 29 - Dec 1). Erin will talk about a management plan for soybean aphid, particularly with suspected pyrethroid resistance in Iowa. Matt plans to talk about pollinators in field crops. In Minnesota, the governor proposes restrictions on neonicotinoids in agriculture and the implications for that are largely not understood. Also, the recent merger discussions between Bayer Crop Science and Monsanto also could change the ag industry in the U.S. and around the world.
[Apologies for the poor sound quality of Erin's microphone]
In this podcast episode, Matt and Erin recap a few extension activities they recently participated in this week. It started with being an "expert" at the Iowa State University display building in the 2016 Farm Progress Show near Ames, IA. Both Matt and Erin helped answer questions about entomology and agriculture, and they also learned from the other displays in the building (something about underwear?). One of the main attractions was a monarch butterfly display and also samples of a new invasive weed, palmer amaranth. Matt also saw a cool UAV display with potential use in site-specific management. Erin also was a judge for a regional crop scouting competition for high school students. It included two teams each from Iowa, Indiana and Nebraska. There are some bright, young agronomists out there. Erin switched gears to talk about pest updates in Iowa, but crops are quickly maturing and the time to make treatments is generally done for this growing season.
The podcast took a break while Matt was on vacation and Erin was on the extension circuit. But they're back and talking about recent pest activity in Iowa. First, Erin shares updates about treating for soybean aphid in northern Iowa. Populations were erratic, as usual, and some fields exceeded threshold in early- to mid-August. A few people noticed poor performance of bifenthrin, a pyrethroid, for soybean aphid. This isn't a huge surprise, given there are pyrethroid-resistant populations in southwestern and southcentral Minnesota in 2015 and 2016. It is important to assess insecticide efficacy and determine potential issues with soybean aphid. In general, soybean are approaching mid- to full seed set throughout Iowa and yield responses are not consistent when applied after full seed set.
In addition, Erin has noted some corn fields with abundant aphid populations. Some fields exceeded 1,000s per plant and were treated with aerial applications last week and this week. Economic thresholds for these pests are not well defined, but Erin has an ICM News article to take into consideration.
Matt and Erin will be at the 2016 Farm Progress Show near Boone, Iowa on August 30. Erin will be at the ISU Event Tent in the morning and have a presentation at 10am. Matt will be there in the afternoon - so stop by and see them!
This podcast episode focuses on a few recent pest updates, like soybean aphid, twospotted spider mites, and a mix of defoliators. Matt talks about spider mite activity in some of his research plots and also in fields near Brookings, SD. Erin notes soybean aphid activity is down throughout Iowa and they both revisit the economic threshold for this common pest. To read more information about why the economic threshold for soybean aphid remains consistently at 250 per plant, read this webpage co-authored by many university entomologists. Finally, Matt shares a research update on the release of parasitic wasps that like to feed on soybean aphid.
Don't drought this episode was a good one. Matt shares an update on the Iowa drought and encourages people to use the U.S. Drought Monitor as a tool to measure landscape moisture levels. Matt and Erin transition and talk about pest activity around the state, starting with twospotted spider mite. Erin wrote a recent ICM News article that talks about scouting and managing this pest that favors hot and dry conditions. Spider mites can be first detected around field perimeters and then eventually infest the field interior. Discoloration, webbing and stunted plants are often the result of heavy spider mite feeding. Erin mentioned a new miticide, AgriMek, that has promise for suppressing mites in corn and soybean; find the label here. The conversation switched gears to talk about some corn silk clipping pests, like Japanese beetle and corn rootworm adults. Scouting to determine pest densities and potential interference with pollination is important. Learn more about Japanese beetle ID, scouting and management with an ICM News article.
Twospotted spider mite. Photo by Frank Peairs, www.ipmimages.org.
Bean leaf beetle. Photo by Marlin Rice.