Counting bugs for better crops

Monday, August 30, 2010
Kelsey Trejo, a senior at Remsen St. Mary's, helps gather aphid-resistant soybean plants to county the number of aphids on them versus on the non-resistant variety. Several students are helping Remsen St. Mary's teacher Paul Mugge with the crop project.

In farming, sometimes answers comes from the plants themselves.

Paul Mugge says a type of aphid-resistant soybeans, cultivated from existing soybeans, is proving to be quite successful.

How does he know?

He's been counting the aphids.

The Remsen St. Mary's teacher and organic farmer is trying out the resistant beans as an option for farmers to beat the bugs without spraying.

"Aphids are one of the biggest pests for soybeans," Mugge said. "And aphid populations can explode extremely quickly."

An Iowa State University professor, Dr. Walter Fehr, found and cultivated an aphid-resistant gene in soybeans.

It is conventionally bred, not genetically modified, so it's approved for organic production, Mugge said.

"Thank goodness they found those genes," he said. "It actually kills the aphids and also, it provides some tolerance that the plants will yield better even in the presence of aphids."

Mugge and four other farmers in Iowa started raising the aphid-resistant soybeans in fields this year.

In Mugge's field, the beans are set up in a striped pattern. There's rows of aphid-resistant beans then rows of the same variety of beans minus the resistant gene side by side.

That pattern runs four times in Mugge's field.

To test how resistant the soybeans are, Mugge and a group of Remsen St. Mary's student volunteers are counting the aphids from each of the eight sample rows.

Early results are positive.

Mugge shared some of the numbers at a field day Saturday at his farm.

"There were dramatic difference between the beans that are resistant and the beans that are susceptible with just the first counting," Mugge said.

Before harvest, he and his crew of Remsen St. Mary's seniors will count aphids a total of four times. That means pulling 20 plants from each sample and counting the aphids on each plant.

The first counting took more than four hours for four people.

"And if there are more aphids it takes a lot longer," Mugge said.

They send the numbers to the entomologist in charge at Iowa State University.

"Ultimately, of course, what he's hoping to show is that this really works, that farmers can plant resistant beans and not have to spray insecticides," Mugge said. "The goal is to keep a lot of insecticides out of the environment."

Finally, the sample strips will be harvested.

"The yields will be measured at the end to find out if it actually works," Mugge said. "At this point it seems to be."

If so, Mugge plans to sell his harvest for seed.

Students also helped present some of the findings at Saturday's field day.

Mugge hopes to apply for a Scholastic Books grant that helps pay for green projects with students so he can continue this study. Many insect and plant studies like this one run three years, he explained.

"Hopefully they can learn something here about ecology and working with the entomologists, agronomists and ecologists at Iowa State, hopefully it will be a win-win for everyone," Mugge said.

Aphid-resistant soybeans are just part of the picture as far as possibilities for farmers that eliminate the need for spraying, Mugge said.

He also manages a strip of reconstructed prairie on his land.

The idea, he said, is to provide habitat for insects that might be beneficial to farm crops.

Mugge has been doing insect collections in his bean fields to find out if the bugs are moving from the prairie to fields and doing any good.

"There are a lot of different insects," Mugge said. "Ladybugs, little wasps, beetles and all sorts of different things, spiders. There's just a whole community of bugs out here."

Beneficial insects, he said, are the ones preying on the not-so-beneficial insects.

"Ladybug larvae actually eat a lot of soybean aphids," Mugge said.

He helped with an ISU project last year at a research farm near Calumet that involved releasing tiny wasps known to lay one egg in each aphid. The young wasp then eats the aphid from the inside out.

"If you're a soybean farmer, that's kind of a pleasant thought," Mugge said.

The wasps are so small, they don't sting people, he added.

The study involves watching to see if the wasps establish themselves in the soybeans and help eliminate aphid problems, Mugge said.

Scientists working on these kind of projects often need a place to try them out in real life, Mugge said.

He is on a list with other farmers that are willing to work with them.

And, depending on the results of the studies, farmers might have a new way to beat some challenge.

Like aphids, for example.

"It's a very good collaboration," Mugge said.

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