Are you “From the first time I met Clay, I knew he was 'special'. Even among all the eccentrics and brainy types at Harvard and MIT, he stood out with his unique way of looking at things and his unconventional way of solving problems. He talked about the farm a lot, but I thought he just liked shocking everyone by telling them he was an Iowa farmboy studying engineering at Harvard. I underestimated his commitment to farming and the vision he had for changing the industry.”

For North Dakota no-tiller Gabe Brown, failure isn’t an option - it’s a requirement. That’s because Brown believes that constant change drives an ever improving system. “We want to fail at something on this farm every year” says the Bismarck area producer who crops ~ 1500 acres and grazes ~ 2000 acres. “If I don’t fail at something, I’m not trying enough things.”

200+ cow/calf operation An appetite for experimentation tempered by cautious risk taking forge a successful operation. Pioneering Illinois Farmer Recounts Transition to Organic Jack Erisman Goldmine Farm in Pana, IL acres certified organic

Biological Soil Fertility Management

Diabrotica virgifera Diabrotica barberi Western corn rootworm beetle Northern corn rootworm beetle What do you know about rootworm biology ??

Goose necking

So how should we manage for corn rootworms ?

Historically, 50/50 corn/soybean rotations provided good control

Soybean variant western corn rootworm In some regions of the Midwest, corn : soybean rotation is no longer an effective method of managing corn rootworm. A variant of the western corn rootworm has evolved with reduced attraction to corn. This is causing a steady and substantial increase in larval damage in first-year corn that has followed another crop. While corn was its only host, the soybean variant western corn rootworm now can migrate to neighboring crops, such as soybeans, where it then lays eggs. These eggs hatch the next year when the field rotates back to corn.

Extended diapause northern corn rootworm Another survival adaptation of corn rootworms is when the northern corn rootworm eggs remain dormant, or in diapause, through two winters and one growing season before hatching. In a rotation where corn is planted every two years, the eggs hatch when corn is back in rotation, resulting in damage to first-year corn. A small portion of the eggs will actually undergo a three-year extended diapause, making even a three-year rotation ineffective. Damage can be extensive, but varies from year to year, even in fields with a history of the problem. Extended diapause has only been observed in northern corn rootworm.

Advertisements for BT corn are everywhere you look…

Are you using BT corn ? Are you abusing BT corn ?

At a U of I trial in 2006, Herculex RW hybrids had surprisingly high levels of rootworm damage

Root ratings in U of I crop rotation studies in 2007 showed very low levels of corn rootworm feeding, regardless of how many years corn had been grown in sequence, and regardless of whether Bt corn or soil-applied insecticide had been used. These results indicate that variation in weather and other factors that change from year to year are more important in determining yield response to corn rootworm controls than are the number of years of sequential corn. In 2007, return on investment in BT corn was probably poor on many farms in IL.

Significant rootworm injury to the roots of an HxXTRA hybrid from the DeKalb site in (University of Illinois) Significant rootworm injury to the roots of a YieldGard VT hybrid from the DeKalb site in (University of Illinois)

“For a few years now, we have observed variability in levels of rootworm injury among rootworm Bt corn hybrids, which was evident again in The level of injury to rootworm Bt corn hybrids at DeKalb and Urbana ranged from approximately 1/2 to more than 1- 1/2 nodes of roots pruned, an amount of rootworm injury that many growers won't expect. It seems that conditions at the trial sites may play a role in this variability, and relative abundance of variant western corn rootworms may also play a role. Variant western corn rootworms (females will lay eggs in soybean fields) are firmly established in the areas around DeKalb and Urbana, but they are less well established near Monmouth and Perry. Regardless of the causes for such variability in protection against corn rootworms, it is evident that rootworm Bt corn hybrids are not silver bullets against corn rootworms.”

Scientists at the Plant Genetics Research Unit, Columbia, Missouri, have been studying the development of resistance to transgenic BT corn. Western corn rootworm colonies have been exposed to transgenic roots as larvae varying from full rearing on transgenic corn to no exposure. Progeny from the sixth generation of selection for survival on Bt corn were evaluated in a small-scale field trial for larval establishment (no adult emergence allowed). Establishment on Bt plants was between 12 and 45 fold greater for the rootworms that were reared on Bt corn (6 generations) than for rootworms reared on the same isoline of corn without BT.

The statewide average density of second-generation European corn borers in Illinois this summer was 9.61 larvae per 100 plants, or larva per plant, the lowest density ever determined, with the density in 2007 being the second lowest. Across the state, only 13% of the 504 corn plants examined were infested with second-generation European corn borer larvae. Zero European corn borer larvae found in 438 of 504 fields, 87% of the fields surveyed. Zero second- generation European corn borer larvae were found in 17 of the 51 counties surveyed. The impact of transgenic Bt corn on European corn borer populations in Illinois has been dramatic. However, weather also probably played a role in reducing European corn borer densities in Illinois in Heavy rainfall events in some areas of Illinois is likely to have caused mortality among the European corn borer moths, contributing to the overall mortality of European corn borer populations caused by Bt toxins.

In North and South America, corn rootworms are attacked by a wide range of pathogens, nematodes, predators and parasitoids, some of which appear to be specialized natural enemies of corn rootworms. Studies have shown that many of these natural enemies are more common in reduced-tillage systems, and in fields with higher levels of organic matter. Nematodes and fungi that attack corn rootworms have been studied as possible biocontrol products. Soil insecticide use reduces the survival of generalist predatory insects and mites.

Many predators feed on corn rootworms European entomologists are trying to identify natural predators of corn rootworms (collected from soils in N. and S. America) for use in controlling corn rootworms in Europe (where rootworms are not native)

When damaged by corn rootworms, the roots of some corn plants release a chemical called (E)-β- caryophyllene that recruits an entomopathogenic nematode (Heterorhabditis megidis) to feed on corn rootworms. Corn breeding has resulted in loss of the (E)-β-caryophyllene signal in some varieties, drastically reducing their ability to recruit H. megidis. Under field conditions, the infection rate of corn rootworms with H. megidis were found to be 5x higher on a corn variety producing the below-ground signal than on a variety that does not. Moreover, spiking the root system of a non-producing variety with synthetic (E)-β- caryophyllene decreased the emergence of corn rootworm adults by > 50%.

Many entomopathogenic nematodes feed on corn rootworms

Galled root system of tomato infected with root-knot nematode, Meloidogyne sp., compared with non-infected root system Root knot juvenile penetrating a tomato root

Entomopathogenic nematodes feed on the larval stage of many insects

Entomopathogenic nematodes are a standard control for some pests Treatment schedule Culturing nematodes in the lab

? competitionparasitism antibiosis induced resistance

What can T-22 Planter Box do for Row Crops? ·T-22 protects roots from diseases caused by Pythium, Rhizoctonia and Fusarium and permits stronger, healthier root systems. · It allows greater soil exploration by the roots and therefore enhances nutrient and moisture uptake and improves tolerance to stressful growing conditions. T-22 improves yield in stress conditions. · It extends root protection beyond seed treatment chemicals. It is not a complete replacement for seed-protectant treatments.

How do I apply T-22? ·No special equipment required. ·Apply T-22 Planter Box powder to seeds at planting. In-furrow spray recommendations are available. ·T-22 can be applied to seeds that have a chemical fungicide seed-protectant coating. ·T-22 is compatible with legume inoculants.

In 1998, the effect of T-22 on corn yield and response to N was evaluated in a commercial grower’s field. The entire field was planted in bands six rows wide with seed treated with T-22 Planter Box alternating with six rows without the biocontrol agent. Ammonium nitrate, was banded and incorporated beside rows of corn at about the four-leaf stage to provide 20, 40, 80, 160, and 240 kg of total nitrogen per ha. (lbs/ac = 0.89 *kg/ha)

. Differences were observed almost immediately. Plants with T-22 responded more rapidly and remained larger and greener for most of the growing season. Maximum silage and grain yields occurred at 150 kg of N per ha in the presence of T-22. The full rate of 240 kg/ha was required for maximum yields without T-22. Maximum yields were similar (~ 220 bushels/ac) with and without T T-22 applied Control

Results

With the help of Trichoderma, fertilizer needs of crops are reduced by 30% -50%. Yield increases rather than decreases with fertilizer reduction. The farmers can save as up to two- three bags of fertilizer. It is important that the fertilizer use be reduced to get the full benefits of the technology. If fertilizers are not reduced, no yield increase will be observed and no benefit from the technology can be observed. The fungus simply does not do its job if fertilizers are abundant. Trichoderma inoculant is not only a good biofertilizer, it is also a good biocontrol agent of soil-borne fungal pathogens. If the field has a history of fungal diseases of vegetables, rice or corn, it should be incorporated in seedbeds or in the field at least three days before seed sowing. In this manner, Trichoderma has enough time to kill the pathogens before they are able to infect seeds and seedlings. Results in the Philippines

Journal of Economic Entomology Article: pp | Abstract | PDF (1.44M) Disruption of Host Location of Western Corn Rootworm Larvae with Carbon Dioxide E. J. Bernklau, E. A. Fromm, and L. B. Bjostad Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO Elevated concentrations of carbon dioxide (CO2) prevented western corn rootworms from locating the roots of growing corn in behavioral bioassays conducted in soil tubs. When CO2 was pumped into one end of a soil tub, significantly more larvae were recovered from soil at the treated end than from soil around a growing corn plant at the opposite end of the tub. In controls with ambient air pumped into one end of a soil tub, significantly more larvae were recovered from the soil around the corn plant than from soil on the treated side. Larvae were unable to locate the roots of corn seedlings when CO2-generating materials were mixed into the soil.

This photo was taken in Ohio on Oct 29, about 6 weeks after aerial seeding and 4 weeks after corn harvest.

Most soil microorganisms are in a dormant state waiting… For their prince charmings to arrive ! Wake up Sleeping Beauty !!… its time to eat some corn rootworms !

Why did we spend so much time talking about root ecology ? Isn’t this a class on soil fertility ?

Understanding nutrient uptake Transpirational stream H20H20 H20H20 Root exudates activate soil microbes Root growth N, S, P Diffusion NO 3 - H 2 PO 4 - K+K+