A team of researchers from Washington State University and the University of Georgia have found that organic farming increases biodiversity among beneficial, pest-killing predators and pathogens. In potato crops, this led to fewer insect pests and larger potato plants.
“It’s always been a mystery how organic farmers get high yields without using synthetic insecticides,” says co-author Bill Snyder, associate professor of entomology at Washington State University. “Our study suggests that biodiversity conservation may be a key to their success.”
Ecosystems with more total species, and more beneficial species that are relatively evenly distributed, are thought to be healthiest. The use of insecticides harms biodiversity by reducing the number of species and by making some species (often pests) much more common than others. The study, which was funded by USDA’s National Institute of Food and Agriculture (NIFA) and published in the July 1 edition of the journal Nature, shows that organic farming practices lead to many equally-common beneficial species, and that this reduces pest problems.
In potato fields that used conventional control practices (e.g., applications of broad-acting insecticides), usually just one species of beneficial predatory insect or pest-killing pathogen was common. In contrast, in organic fields several beneficial species were about equally common. Experiments showed that groups of evenly-abundant beneficial species, typical of organic farms, were far more effective at killing potato beetle pests. Because natural enemies are usually more even in organic crops of many different kinds, not just potato, these benefits could be widespread.
NIFA funded this project through the National Research Initiative Arthropod and Nematode Biology and Management competitive grants program.Through federal funding and leadership for research, education and extension programs, NIFA focuses on investing in science and solving critical issues impacting people's daily lives and the nation’s future.
Recent Trends from Farms To Consumers
Organic foods now occupy prominent shelf space in the produce and dairy aisles of most mainstream U.S. food retailers. The marketing boom has pushed retail sales of organic foods up to $21.1 billion in 2008 from $3.6 billion in 1997. U.S. organic-industry growth is evident in an expanding number of retailers selling a wider variety of foods, the development of private-label product lines by many supermarkets, and the widespread introduction of new products.
A broader range of consumers have been buying more varieties of organic food. Organic handlers, who purchase products from farmers and often supply them to retailers, sell more organic products to conventional retailers and club stores than ever before. Only one segment has not kept pace—organic farms have struggled at times to produce sufficient supply to keep up with the rapid growth in demand, leading to periodic shortages of organic products.
U.S. Department of Agriculture