Beneficial insects save an estimated $4.5 billion per year for American farmers.
Researchers at North Carolina’s Center for Environmental Farming Systems are trying to up that ante by developing a number of plant species that fit into farming systems in the Southeast and increase the number of beneficial insects and improve the environment without negatively affecting crop production.
“The trend in the Southeast is to plant more acres, and in some cases from fence row to fence row. In cases like this growers tend to lose some of the synergism created by the mixing of beneficial insects, wildlife, parasites and pollinators,” says North Carolina State Entomologist David Orr.
He is part of research team from North Carolina State University working on ways to enhance the value of predators and parasites on the farm. Seeding plants that provide a food resource and a good environment to over-winter is one way to enhance the value of beneficial insects, Orr adds.
“The whole idea is to reclaim some of the diversity of the landscape that is lost when farms go to large expanses of the same crop. Research indicates that once you lose 20 percent of the natural vegetation in a farm landscape, you begin to lose the services of natural predators, parasites and pollinators,” he says.
The cost of losing this balance of nature is high. From an ecological standpoint native species of wildlife begin to disappear, which further diminishes the value of beneficial plants, often leaving farmers with no other option than synthetic pesticides.
Under current production practices, which are vital to producing the quality and quantity of crops needed to feed the world, it would be virtually impossible to continue to build production without the use of these materials.
Each year U.S. farmers spend an estimated $1.5 billion on insecticides to protect their crops. Without insecticides some crops would lose up to 70 percent in yield losses and over the entire crop spectrum, the loss of crop value would be catastrophic for U.S. growers.
The Center for Environmental Farming Systems (CEFS) is not trying to replace the use of insecticides. The beneficial insect and habitat improvement projects under way at the Center are geared to providing some natural deterrents to harmful insects, giving growers some management options to augment their use of insecticides.
Simply adjusting tillage can provide some help in reducing dependence on insecticides to manage insects.
In studies across the Southeast, insecticide costs under conservation tillage are $50-$100 per acre less than conventional crop management, across the board on a large number of crops.
By using Bacillus thuriengsis and other naturally occurring insect control tools growers can reduce the use of pesticides that can reduce natural predator populations.
By planting cover crops on field edges and in other non-crop areas, farmers using non-conventional production practices can increase the number of beneficials and improve crop production in unison with reduced insecticide use.
Want right kind of wildlife on farm
Chris Moorman, a wildlife biologist at North Carolina State says most farmers want more wildlife on their farms, but they want the right kind of wildlife. Having more deer or more wild hogs, for example, could be a bad kind of wildlife to develop.
Birds, on the other hand, are almost universally good for farmers. Not only do birds eat insects that can harm crops, they also are heavy feeders of seed from weeds and other unwanted plants.
The changes that have occurred in agriculture in North Carolina over the past decade or more have not been good for wildlife, Moorman says. “If you drive across Eastern North Carolina, for example, you see crop land separated by a fence or a ditch, followed by another field.
“Eventually you get to the end of a series of fields and you see woods. This is a sterile habitat for wildlife, and most species just can’t survive in this type environment,” Moorman says.
“To make things worse, many growers mow ditch banks and fence rows and along the edge of cropland. This further reduces the structure that could provide habitat for wildlife,” he adds.
A good alternative to this type land management on farms is to establish a field border. A good place for a field border is along the edge of wooded areas. These areas in the field are not likely to be productive because crops will be competing with trees and bushes for sunlight and nutrients.
Planting cover crops and plants that are preferred by beneficial insects and by wildlife can easily offset the cost of crops lost in these areas.
Another good place for field borders are along ditch banks. Field borders along ditches can provide excellent habitat for wildlife. Perhaps more importantly in some areas, field borders can filter water contained in these ditches and significantly reduce erosion problems, Moorman says.
There are cost share programs from the federal government to greatly lower the cost of constructing these barriers.
However, the typical manner of producing field borders in North Carolina is essentially doing nothing. Land is allowed to go fallow and whatever comes up is considered a field border. Unfortunately, ‘what comes up’ is too often pigweed and other plants you don’t want on your farm, the north Carolina wildlife biologist says.
A study at the CEFS looked at the comparative value of fallow barrier compared to planted barriers that produce plants which provide good habitat for host plants for beneficial insects and for desirable wildlife species.
Bobwhite quail have been big in the news the past few years. Quail and quail hunting were a part of the social environment in the South for more than 100 years, and now quail populations in some parts of the Southeast are almost extinct.
“We planted wildflowers like sunflower, Rubeccia, and purple comb flowers, which are good for beneficial insects. What we found was that these planted barriers were just as beneficial to quail and other desirable wildlife as were the fallow barriers.
“The reason is quail and other wildlife don’t seem to care much about the species composition, but they really need the structure,” Moorman says.
In the Upper Southeast, these planted barriers, which may be as small as 30 feet wide, by 300 feet long can make a difference with beneficial insects and some beneficial birds. Quail and other larger wildlife will need much larger areas of barriers to make a difference.
In the Southeast these barriers need to be disturbed every 3-4 years. Otherwise, these areas will be dominated by trees, which won’t provide the structure needed by beneficial insects and wildlife species, Moorman says.