BUGGIES IN THE BIOFUELS MIX – OH, MY!!!!

Don’t know if I’ve mentioned this before, but WonderWife and I are avid gardeners. We’ve got about 1 ½ acres in a truck garden set-up at the farm, and most of our backyard is taken up with fruit trees and a garden. There’s something wonderfully soothing and interesting in watching things grow, even if the weed population sometimes outstrips the food production.

Last year, we had about 1/3 of both of our gardens planted in several different varieties of corn, and we didn’t harvest any more than a bushel from each plot to due to a pesky little critter called the western corn rootworm beetle, which is a pest that feasts on corn roots and corn silk. They are black, small, and have pointed snouts that look like sharp knives on each side. "The rotation-resistant rootworm is the population that is most familiar and troublesome to farmers in Illinois," said Joseph Spencer, an insect behaviorist at the State Natural History Survey and co-author on the study with former Survey scientist Sathyamurthy Raghu.
"This form is spreading across the Corn Belt, putting a greater area of U.S. corn production at risk each year. The worst rootworm was happy on Miscanthus," Spencer said.

OK, so who is Miscanthus and why should anybody care about it?

The western corn rootworm beetle that feasts on corn roots and corn silk, and additionally costs growers more than $1 billion annually in the U.S., also can survive on the perennial grass Miscanthus x giganteus, a potential biofuels crop that would likely be grown alongside corn because the two are complimentary crops. Rootworm beetle larvae can survive to adulthood on Miscanthus rhizomes, and adult beetles will lay their eggs at the base of Miscanthus plants grown near cornfields, the researchers found. Their study, in the Public Library of Science journal PLoS ONE, is the first to identify Miscanthus as a host of the corn rootworm. This is NOT a good thing, either, since the beetles migrate.

The research team, from the University of Illinois Natural History Survey, tested several rootworm beetle populations on Miscanthus, adding rootworm eggs to potted Miscanthus and corn plants in a greenhouse setting. Here’s what they found out – and it’s NOT good news:

Rootworms from all populations survived to adulthood on the Miscanthus plants, including a strain that is behaviorally resistant to crop rotation. (Rather than remaining true to cornfields, rotation-resistant rootworms also will lay their eggs in soybean fields and other rotated crops, allowing the larvae to feed on corn planted in those fields the following spring.) This, again, is NOT a good thing, either for the production of stock for biofuel production, or, more importantly, production of food stuffs for people to eat.

"The rotation-resistant rootworm is the population that is most familiar and troublesome to farmers in Illinois," said Joseph Spencer, an insect behaviorist at the State Natural History Survey and co-author on the study with former Survey scientist Sathyamurthy Raghu. "This form is spreading across the Corn Belt, putting a greater area of U.S. corn production at risk each year. The worst rootworm was happy on Miscanthus," Spencer said.

Although the researchers found about 70 percent fewer adult rootworm beetles on the Miscanthus plants than on the corn plants grown in the greenhouse, the fact that rootworms could survive at all on this perennial grass was a revelation, Spencer said. "That we can get as many insects as we were getting tells us that this plant is not a bad host for these insects," he added.

Some adults emerged from the Miscanthus slightly earlier than they appeared on corn. More emerged slightly later than those on corn, Spencer said, but the timing of their emergence was close enough that "there's the possibility that adults coming off these two crops could interact." This interaction could be good or bad for corn growers, Spencer said (Personal opinion here: NOT GOOD). If the rootworms that grow up on Miscanthus carry genes that make them susceptible to transgenic corn or to any sort of insecticides used on corn and they mate with rootworm beetles in a cornfield, it could help slow development of resistance to insecticides or transgenic corn among their offspring.

On the other hand, the acres devoted to Miscanthus could function as a vast, perennial reservoir of rootworm beetles - with devastating consequences for corn growers. To determine if the western corn rootworm would lay its eggs in a Miscanthus field, the researchers placed potted Miscanthus plants in rows next to a cornfield during the egg-laying period. Late in the season, before the corn was harvested but after the rootworm adults were all dead, the researchers counted rootworm eggs in the soil around the corn and Miscanthus plants, and in the space between the rows of plants. "There was no difference in the mean number of western corn rootworm eggs laid at the base of Miscanthus and maize in the field," the authors wrote. The implications for corn growers are not yet known, "but these findings brought it home to us that much more study is needed," Spencer said. "Before we put something out in the environment that could result in pest problems increasing on corn, we need to more fully appreciate the ecology and potential interactions in the environment."
So, why is this important? Well, first of all, ecological concerns aside, it’s a proven fact that, short of using DDT on the various different kinds of bugs that are infesting the grain fields, there’s nothing that will kill everything indiscriminately. It’s like trying to bug bomb cockroaches; there are always survivors, and those survivors are resistant to the chemicals used. Even if you vary the chemicals every time, or use different chemicals in concert, there are always survivors, and they are resistant to the chemicals as well. Eventually, as the survivors breed, their progeny becomes completely immune to any chemical or chemical mix that is currently publicly available. Unless a neurotoxin like Chlordane or Bt is used every time, and within a 3 week period, eventually the cockroaches come back, worse than ever.

Same thing is true of any insect species. They are incredibly adaptable and they do survive. According to the US Department of Agriculture, corn rootworms cause $1 billion in lost revenue each year, which includes $800 million in yield loss and $200 million in cost of treatment for corn growers. Lower yields means less feedstock for biofuels and for farm animal and human consumption. Put the Miscanthus next to a cornfield, and you are, basically, doubling the potential losses because the Miscanthus beetles hatch earlier, live longer, and migrate. To the grain field.
So, crop rotation doesn’t really work and using chemicals only works for a while – and, even if there’s only one generation of the beetles every year, the ones in the grass hatch earlier and migrate while the ones in the grain fields hatch later, and both sets eat until they start laying eggs.

So, what to do about this? At this point, nobody knows. All that we can do at this point is study the critter. Maybe genetic manipulation will be used, to make the generations progressively more sterile until they die out altogether. Only problem with that is this: What will Mother Nature come up with that will be worse?