URBANA, Ill. — A new wave of invasive plant pests are poised to spread from Central to North America crop fields and forests, the USDA acknowledged in recognition of its Invasive Plant Pest and Disease Awareness Month this April.
Of possible major consequence to U.S. farming operations is the Old World bollworm, considered by crop producers in Brazil and by the USDA as a serious threat to agriculture that could disrupt commercial production of corn, cotton, small grains, soybeans, peppers and tomatoes.
"The Old World bollworm (Helicoverpa armigera) is a pest of growing concern," said Mike Gray, University of Illinois at Urbana Department of Crop Sciences professor and assistant dean, in an email reply to questions. "(Growers) and extension entomologists in the southeastern USA are most likely to encounter this pest first."
The USDA Animal and Plant Health Inspection Service (APHIS) is asking farmers and the public to report any sightings or production losses caused by the Old World bollworm. APHIS’ recent "most wanted" invasive pest list also includes the coconut rhinoceros beetle – responsible for the destruction of many species of palm trees in Hawaii – and the spotted lanternfly, which could impair the nation’s grape, orchard and logging industries.
"We can all play a role in stopping the spread of invasive pests during the course of our regular activities, from enjoying the outdoors to travelling to internet shopping," said Osama El Lissy, deputy administrator of APHIS Plant Protection and Quarantine program.
APHIS issued consumer tips for helping keep invasive pests and diseases out of the United States, and controlling those that slip in. They include buying firewood where you plan to burn it; avoiding carrying or mailing fresh produce or plants from one state to another; and declaring plants and produce to Customs and Border Protection officials when returning from international travel.
Evidence of invasive pests such as the Old World bollworm can be reported at www.HungryPests.com which is an APHIS website that includes photos and descriptions of 18 invasive pests, an online tracker of federal quarantines by state and more.
Gray referred to an August 2014 article about the Old World bollworm published in Scientific American that estimates annual worldwide agricultural losses from the pest at $5 billion. The "incognito" caterpillars appear identical to the common North American corn earworm, Helicoverpa zea, making the task of properly identifying the voracious pest a daunting challenge for producers.
The bollworm consumes more than 180 kinds of plants in all, and a single female can lay thousands of eggs. The species is on APHIS’ radar largely because of the ability of adult bollworms to ride wind currents up to over 1,200 miles, or about the distance from Mexico City to Albuquerque.
The Old World bollworm was confined to Africa, Eurasia and Oceania until 2013, when it was found attacking soybean and tomato crops in Brazil, reported Scientific American’s Nala Rogers. The species has since been identified in Argentina and Paraguay and is believed to be migrating north, top entomologists and researchers agree.
"It can tolerate a wide range of environmental conditions, it can eat lots of different hosts and it can fly great distances," noted Tom Walsh, one of the researchers who first identified Old World bollworms in Brazil. "So there is no reason why it won’t move up through Mexico."
Bruce Tabashnik, professor of entomology at the University of Arizona in Tucson, said though Bt toxins still work on bollworms, researchers are having no trouble breeding Bt-resistant bollworms in the lab, and resistant individuals are regularly found in crop fields.
"The really scary part about the potential of (bollworms) moving into the United States is that they will be coming from a place where they’re going to be selected intensely for resistance to Bt toxins. So we’re unlikely to get (bollworms) that are susceptible," he explained.
USDA is funding research identifying adult bollworm moths caught during surveys, along with examining molecular methods to identify caterpillars at U.S. ports of entry, according to APHIS.
The USDA is also reaching out to producers to help identify destructive invasive species that manage to make it into U.S. crop fields and forestry operations. "USDA-APHIS remains vigilant in safeguarding our nation from invasive species abroad, at our borders, and across the country, but it’s critical that each of us does his or her part to prevent the introduction and establishment of invasive species in a new area," said El Lissy.
