PROviding production options

Research into pesticide-reducing farm methods, from monitoring to biological controls, continues to pay off for farmers

By Andrea Frazeur

AURI’s PRO — Pesticide Reduction Options — program distributed over $200,000 to seven projects this year, marking the program’s fifth grant round. Projects range widely in scope and methods, but ultimately have one purpose — to improve crop production and farm methods while reducing petro-chemical use.

PRO funds two-year research and demonstration projects, with average awards of $30,000. Beneficiaries range from wheat farmers and seed companies to vegetable and bean growers.

“We’re looking to impact agriculture as much as possible,” says Brent Sorenson, manager of AURI’s Crookston field office. “We focus on mainstream production as well as sustainable ag and organic. We want to make sure everybody can take part in PRO.”

Sorenson and Ed Wene, AURI microbiologist, oversee PRO along with Donna Christianson, AURI contractual services specialist. The team evaluates proposals to determine if they fit in PRO guidelines and asks University and industry experts to review applications.

Many PRO projects uncover promising directions for future research, and receive continued funding. Some of the projects highlighted here represent years of dedicated investigation to provide sensible solutions to crop production problems.

On the lookout for aphids
Ian MacRae, UofM Extension entomologist, en-courages farmers to take walks in their wheat fields.

“It’s a hard sell,” MacRae says. “These growers have a lot on their plate. To ask them to do extra work and take extra hours is not a small thing.”

But MacRae’s research sug-gests that the hour it takes to scout an 80-acre wheat field for aphids might save the $240 cost of treating those acres if the treatment isn’t warranted.

Some farmers think merely spraying insecticides is a cheap insurance policy against aphid damage. “What we’re trying to get across is it might not be so cheap,” MacRae says. “In most cases, after wheat has headed, you’re not going to get an economic return.”

Aphids are small insects with piercing, sucking mouthparts that cause long-term damage to wheat. They puncture the plant, suck the juices, and hang on until wheat reaches maturity.

In the last five years, farmers in northwestern and western Minnesota have also battled fusarium head blight, commonly called scab, a fungal disease that reduces yield and quality in small grains. The disease has cost Minnesota and North Dakota farmers more than $200 million in recent years.

Farmers are anxious to apply fungicide at the correct time to combat scab. Custom applicators may suggest farmers spray insecticide for aphids simultaneously with scab fungicides. However, the correct time to spray for scab, when the wheat is in the head emergence stage, is too late, economically, to treat for aphids.

The best time for spraying aphids is earlier in the season, and if there are not enough aphids, they may cause little damage anyway. This year, based on 1998 wheat prices, MacRae recommended farmers only spray for the insects if they found more than 83 aphids on 100 wheat plants.

“There have been a few fields that I recommended treating,” MacRae says, “but the vast majority, I would not treat.”

Bt monitoring is sweet
Bill Hutchison knows insects adapt rapidly to their environment. The U of M Extension entomologist urges the ag industry to develop resistance management plans for controlling European corn borer in Bt corn. To help, he has developed an easy method for monitoring corn borer resistance.

“The bottom line is there will be increasing acres of Bt corn planted for another two or three years,” Hutchison says. “We need some sort of practical monitoring system in place.”

Seed companies now market bioengineered Bacillus thuringiensis, or Bt, corn. Bt corn produces a natural toxin that kills corn borers even if the larvae take just a few bites. Bt corn appears to control corn borer better than well-planned Bt insecticide treatments. Nevertheless, seed companies intro-duced the bioengineered strains quickly, without fully developing resistance management strategies. Many companies now suggest that farmers plant 20-30 percent non-Bt corn as a resistance control measure.

Hutchison and U of M graduate student Pat Bolin proved it takes only nine generations in the lab to develop corn borer resistance to Bt. In his most recent PRO project, Hutchison set up Bt sweet corn plots at each of the U of M’s experimental stations.

Hutchison recommends each plot consist of 30 to 50 one-hundred-foot rows, of Bt sweet corn with six rows of non-Bt sweet corn next to the plot. He suggests maintaining at least eight plots and using sweet corn instead of field corn for tests. Corn borers are intensely attracted to sweet corn, especially when planted late.

The Bt corn is checked frequently for signs of corn borer. If any larvae are found, a genetic test taking less than an hour can prove whether the plant contains Bt. If it does, scientists conduct lab tests to determine whether or not the corn borer is resistant to Bt.

“The fact that larvae are present on a Bt plant or ear is a pretty good indication that the larvae carry one or more resistant genes,” Hutchison says.

Hutchison’s work is also important to sweet corn farmers who spray Bt or other insecticides. “This is clearly a useful technology for sweet corn growers, who typically use insecticides more frequently than field corn growers.”

Rooting out the rot
A beneficial bacteria seed treatment may prove effective in reducing edible bean root rot. Jim Percich, U of M plant pathologist, says “We’re exploring the use of biological control so we can try to reduce or eliminate chemical use.”

Currently, the only controls for fungal root rot are chemical seed treatments and fungicide sprays. If spring is cool and wet, root rot can easily develop. The rot kills some of the roots, compromising the bean plant. Farmers have found that if they irrigate frequently, the small root will get enough water so the plant yields. But heavy irrigation is not a good answer; it’s expensive and may have environmental implications.

The U of M team of Percich, plant pathologist Richard Meronuck and student Consuelo Estevez-Jensen hopes to find a good biological control to use alone or in conjunction with fungicides. The scientists think a bacteria seed coating containing Bacillus subtilis may be the answer. As the seed germinates and roots start to grow, the bacteria grows along the root surface, forming a defensive barrier against harmful fungi.

As part of their work, the team also found three out of over 100 kidney bean varieties that show promise for resistance to root rot. “The seed treatment looks very good when coupled with the best resistant material we have in beans,” Percich says.

Over 300 acres of kidney beans near Park Rapids, Minn. were treated with the biological seed treatment. Plants in treated fields were larger and healthier than non-treated fields.

“This biological control targets a very, very specific pathogen,” Percich says. “There is no extra use of chemicals or non-targeted effects.”

In previous projects, a team of researchers pinpointed the specific fungus causing root rot in kidney beans. With that information, they identified proper fungicides to reduce root rot. The team included U of M researchers, North Dakota State University researcher Ken Grafton, the Northarvest Bean Growers Association, and the Central Lakes Agricultural Center.

Research also showed the fungus affects corn and potatoes. In a corn-potato-bean rotation, root rot worsens. “The rotation sustains the pathogens,” Percich says. The rot can also affect peas, soybeans, wheat, sunflowers, alfalfa, clover, sweet corn and many types of weeds.

Their findings were most impressive, says AURI’s Sorenson. “We’re going to plant more and more edible beans in Minnesota. Root rot is going to be an issue as we go into larger and more concentrated acreages. The scientists are trying to find a treatment that can prevent us from applying a bunch of chemicals.”

Finally, to the farm
In Chippewa county, the Sustainable Farming Association of Western Minnesota is interested in alternative weed management systems. Coordinator LeeAnn VanDerPol says the association requested funds for the work of Don Wyse, a U of M agronomist evaluating an integrated weed management system for no-till, conventional and organic soybean production. The system uses bacteria biological controls and weed-competitive soybean varieties.

Although her farm is not included in the study, VanDerPol advocated the research because of her own work in reducing chemicals. VanDerPol and her husband, Jim, started farming in 1977, raising 480 acres of corn and soybeans. They also ran a small hog farrowing operation on Jim’s parents’ farm.

The VanDerPols had difficulty making a living with their conventional system so they sought information on alternative methods. Today the VanDerPols farm 320 acres, and they’ve been able to pay off about half of the land.

They farrow pigs on pasture in the warm months, and in two hooped barns deep-bedded with straw in the cold months.They grow corn, alfalfa, and a combination of oats, barley and field peas, which they put up as feed for their hogs. The stems supply straw for the hog operation.

“We’re not organic, but we have cut our chemical use by quite a bit,” VanDerPol says. “I really would like to encourage farmers to reduce chemical use.”