Bozeman, Montana, USA
August 7, 2014
The midge-afflicted wheat kernels may abort entirely, they may not fully develop or only be slightly damaged. The extent of the damage largely depends on the number of midge larva present. Smaller, immature seeds are the most vulnerable. Photo from MSU Montana Agriculture Experiment Station.
Montana State University and wheat growers across the state are working together to protect the state’s billion-dollar wheat industry from a tiny orange midge capable of inflicting major damage to the crop.
The adult orange blossom wheat midge looks like a small, orange mosquito and lays its eggs on the maturing head of spring and durum wheat. After hatching, the midge larva feed on the developing wheat kernels causing yields to plummet from 80-90 bushels per acre to as little as two. Photo from MSU Montana Agriculture Experiment Station
The adult orange blossom wheat midge superficially resembles a small, orange mosquito and lays its eggs on the maturing head of spring and durum wheat. After hatching, large numbers of midge larvae feed on the developing wheat kernels causing yields to plummet from 80-90 bushels per acre to as little as two.
Because the orange wheat blossom midge larva feed on the developing wheat kernels within the blossom, growers may not realize their crop is being damaged until it is too late. MSU is working with farmers to deploy traps to determine if adult midges are in their fields. The presence of 10 or more adult midges in a trap over a two-day period indicates farmers should scout their fields at twilight when the females fly and lay their eggs. If they see more than one midge per six heads, they know their field is vulnerable to an attack that could hurt the value of their harvest. Photo from MSU Montana Agriculture Experiment Station.
Bob Stougaard, superintendent of MSU’s Northwestern Agricultural Research Center in Kalispell and professor of weed science, said the first economically devastating appearance of the orange wheat blossom midge in Montana occurred in Flathead County in 2006.
“We estimated that our losses in 2006 were at least $1.5 million,” Stougaard said. “That kind of number really gets your attention. We’ve been working on addressing this problem ever since.”
The orange wheat blossom midge is an invader from Eurasia that has plagued certain areas of the upper Great Plains and much of Canada wheat country. While it is known in the Western Hemisphere as a pest of spring wheat and durum, in Europe and Asia it attacks winter wheat.
Although the Flathead Valley was the first area in Montana to suffer severe economic losses due to this pest, the wheat midge has since made its growing presence felt in other areas of the state, putting wheat growers on alert across Montana, Stougaard said.
Experts with MSU Extension, MSU’s Montana Agricultural Experiment Stationand the MSU College of Agriculture have worked with wheat producers to create a state-wide, early-warning detection system to monitor the midge’s spread; are sharing information about strategies to combat the midge through the well-timed application of pesticides and use of biocontrols; and have developed a new wheat variety that is genetically resistant to the midge and which should be available for planting for the 2016 season.
The early-warning detection system involves trapping the midges and counting their numbers. Six Montana Agricultural Research Centers and 26 MSU Extension offices have worked with growers and crop consultants to place hundreds of traps across the state. The cooperative effort, known as the Orange Wheat Blossom Midge Monitoring Project, helped spearhead development of an online information sharing system – MSU Pest Management Network – where findings are mapped and quantified so that grain growers throughout the state can see if midge populations are present in their area and if the numbers warrant action.
The presence of 10 or more adult midges in a trap over a two-day period indicates farmers should scout their fields at twilight when the females fly and lay their eggs. If they see more than one midge per six heads, they know their field is vulnerable to an attack that could hurt the value of their harvest.
David Weaver, a professor of entomology with MSU’s College of Agriculture who also participated in efforts to manage this pest after that first outbreak, said word about how to address the problem has spread thanks to some key players. In particular, Weaver said Dan Picard, a retired MSU Extension agent for Pondera County with a small wheat farm in the Golden Triangle, has taken a leading role in what has been a huge collaborative effort, both to track the insect’s appearance and to educate the farmers.
The Orange Wheat blossom Midge Monitoring Project, which Picard likens to MSU and growers setting up a neighborhood watch – brought Picard out of retirement for short-term contracts with MSU Extension and the Western Triangle Agricultural Research Center.
Both Picard and Weaver said the project is an example of how well integrated MSU is within Montana’s tight-knit wheat community.
“It really is a team effort. People might not be aware of how much the academic community collaborates directly with growers,” said Weaver, an entomologist with MSU’s Montana Agricultural Experiment Station. “Many people think that we work in isolation as researchers, but it’s the classic 'it takes a village' scenario.”
To further help growers, MSU Extension produced a MontGuide on the orange wheat blossom midge, offering critical advice on how to determine the risk. The guide is available as a free download from the MSU Extension Publications Website.
MSU experts have advised growers that spraying – which can be a significant cost – can only benefit a crop if the timing is right, both for the growth stage of the wheat, as well as for the development and hatching of adult midges. The wrong timing of pesticide can prove counterproductive by reducing certain populations of wasps, one of which is a biological control that helps keep wheat stem sawfly at bay, and another that attacks the orange wheat blossom midge.
Luther Talbert, professor of plant breeding and genetics specializing in developing Montana spring wheat varieties, examines a head of Egan wheat in a field at the MSU Arthur A. Post Research Farm near Bozeman. Bred for a gene that prevents the midge larva from developing, Egan represents perhaps the hardest line of defense in the effort to combat the orange wheat blossom midge. MSU Photo by Sepp Jannotta.
Luther Talbert, professor of plant breeding and genetics specializing in developing Montana spring wheat varieties, represents perhaps the hardest line of defense. Soon after the 2006 outbreak, Talbert looked for a line of wheat that might hold promise against the new pest. He found it in an experimental line developed by North Dakota State University.
He cross bred it with several experimental Montana-adapted spring wheat lines that thrive in the Flathead area and have a resistance to the wheat disease, stripe rust. The result was a highly midge-resistant spring wheat dubbed Egan after Egan’s Slough, the location where the pest was first detected in 2006. The new wheat line will go into the seed production next season, with commercial seed to be available in 2016.
“The gene for resistance didn’t exist in any of the 10,000 wheat lines we were evaluating on our breeding program. However, our colleagues in North Dakota and Manitoba (Canada) had developed the tools we needed to breed the resistance gene into our own varieties,” Talbert said. “From our work, Egan rose to the top due to its resistance to the midge, resistance to stripe rust, and its high grain protein.”
A field of Egan wheat, a new, experimental spring wheat line was bred to be resistant to the orange wheat blossom midge, which has been increasingly problematic in Montana and can potentially devastate a crop. Egan will be commercially available for 2016. In the meantime experts with MSU Extension, MSU’s Montana Agricultural Experiment Station and the MSU College of Agriculture have worked with wheat producers to create a state-wide, monitoring system to track the midge’s spread. They also are sharing information about strategies to combat the midge through the well-timed application of pesticides and use of biocontrols. MSU Photo by Sepp Jannotta.
A similar effort is underway to breed varieties for other Montana wheat-growing areas, such as a solid-stemmed variety for the Golden Triangle that is also resistant to another major wheat pest, the wheat-stem sawfly.
“The effort to develop integrated approaches, including developing wheat varieties that can resist pests and disease, gives us an ability to respond relatively efficiently and provide sustainable tools to combat the midge,” Talbert said.
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