The old world bollworm's multibillion-dollar threat

W. Billen, Pflanzenbeschaustelle, Weil am Rhein, Bugwood.org

The old world bollworm (OWB) is a pest that causes billions in damages to agriculture around the world annually, and it isn't a question of if it will come to the U.S. mainland but when.

Also known by its Latin name of Helicoverpa armigera, it's notorious for its diverse and ravenous appetite. The bugs feast on 180 species on wild and cultivated plants such as corn, sunflowers, beans and tomatoes. Larvae bore into the host's flowers and fruit, and feed within them. They also eat their host's leaves, and much to the chagrin on some officials, OWB is showing resistance to insecticides

"The OWB is considered to be one of most significant pests around the world," said Dan Borchert, entomologist at the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS), in a statement to CBSMoneyWatch.

"The arrival of OWB in the Western hemisphere and the rapid spread in South America and into the Caribbean has reduced the distance of OWB from the Continental U.S. and has increased the potential for the pest to arrive in the U.S.," Borchert added. "However, it is not possible to predict when. We are working hard as an agency to prevent the introduction of this pest and prepare for arrival if and when it occurs."

A recently published scientific paper estimates the value of U.S. crops exposed to the pest at $78 billion and notes that $843 million worth of crops are grown in conditions that are ideal for the OWB, which has been found in Africa, Asia, Europe and Australia. Those estimates, however, may prove to be conservative, according to one of the paper's co-authors.

"The odds are very good that it will arrive in the mainland sometime in the near future. It could very well arrive in the Southern U.S. [first]" because it prefers warmer climates, said Bill Hutchison, the chair of the University of Minnesota's Department of Entomology, told CBSMoneyWatch, adding that OWB in its moth and larval stage is impossible to distinguish from a native pest known as a corn ear worm. "There is a possibility that it's already here."

Borchert noted that the corn ear worm is the "twin brother" of the OWB, and he stressed that many of the same pest management strategies could work for the newer arrival. He added that OWB's impact might be limited in the U.S. because much of the corn and cotton planted here is genetically modified to express biological pesticides that would reduce the bug's impact. Some critics argue that such crops are dangerous to human health, a claim the agribusiness industry rejects.

The U.S. cotton industry is among those keeping a close eye on the OWB situation, according to James Pruden, a spokesman for Cotton Inc. "This is something that's on everybody's radar," he told CBSMoneyWatch.

The insect, however, is a formidable adversary. It can fly between six and eight miles, and can travel long distances on of the wind. In Europe, the pest migrates annually between Scandinavia and the Mediterranean.

OWB didn't arrive in the New World until 2013, when it was found in Brazil, and it quickly spread throughout Latin America. The closest the bug has gotten to the U.S. so far is Puerto Rico. As of January, according to the USDA, 20 OWB moths have been found in the U.S. territory. None have been found since then.

"We have not found any damage on host plants, but moths of H. armigera have been trapped from fields with a variety of vegetable and grain crops including beans, pigeon peas, okra, rice, sorghum, and squash," the USDA said. "We continue to conduct delimiting surveys in Puerto Rico to determine the extent of this infestation."

bollworm2.png
Experts fear the old world bollworm could threaten billions of dollars' worth of crops if it arrives in the U.S.
Paolo Mazzei, Bugwood.org

APHIS has recently added OWB to its list of invasive species that pose the biggest threats to the U.S. economy even though it hasn't "officially" arrived. Thwarting its spread won't be easy. For one thing, the bug can generate up to five generations a year, and as many as 11 in warmer climates.

"Given the long lead times, initiating classical and inundative biological control program[s], sterile insect techniques, large-scale pheromone trapping, trap crops at borders would seem prudent activities to initiate promptly," a paper in PLOS ONE said. "It may even be in the interests of the North American countries to co-invest in biological control and spread monitoring programmes in Central America and the Caribbean."

Officials at the USDA note that people can help stop the spread of OWB by not bringing fresh fruits or vegetables into their state or into another state without having them inspected. Federal and state authorities are working together to prevent OWB and other invasive species from getting a foothold in the continental U.S. through inspections at the border and public education campaigns.

The proposed 2015 farm bill contains funding for additional research on OWB along with money for research into the bug's impact on Puerto Rico.

  • Jonathan Berr On Twitter»

    Jonathan Berr is an award-winning journalist and podcaster based in New Jersey whose main focus is on business and economic issues.