Learnings From Latin America: Potential Risk of Helicoverpa armigera to U.S. Soybean Production
By Fikru Haile, Ph.D., Tim Nowatzki, Ph.D., and Nick Storer, Ph.D.
Invasive insect pests are in the headlines, and they are a major topic of discussion among entomologists, international organizations such as the Food and Agriculture Organization (FAO) and International Maize and Wheat Improvement Center (CIMMYT), and governments because of their potential impact on agriculture and food security. Examples are the ongoing desert locust (Schistocerca gregaria) outbreak in East Africa and West Asia, and the spread of fall armyworm (Spodoptera frugiperda) throughout Africa, Asia, and Australia. Prior to the desert locust and fall armyworm examples, the Old World bollworm (Helicoverpa armigera) made headlines when it established in Brazil in 2013.
Prior to 2013, H. armigera had only existed in the Old World. Now, H. armigera is found in most countries in Latin America and is expected to migrate north (aided by wind currents) and establish populations in the continental U.S. Although moths were caught in pheromone traps in Puerto Rico and Florida, there is no confirmation yet of field occurrence in the U.S. If it becomes established throughout its potential range in the U.S., H. armigera could threaten multiple crops collectively valued at approximately $78.3 billion.
In our new article, “Overview of Pest Status, Potential Risk, and Management Considerations of Helicoverpa armigera (Lepidoptera: Noctuidae) for U.S. Soybean Production,” published this month in the open-access Journal of Integrated Pest Management, our team outlines the importance of insecticide resistance management (IRM) and integrated pest management (IPM) guidelines when considering long-term pest management solutions.
Although H. armigera attacks multiple crops, soybean is one of the most preferred and impacted by this pest in Brazil. If this pest establishes in the U.S., soybean will also be at risk from H. armigera, particularly in mid-southern U.S. states such as Mississippi, Louisiana, Georgia, Tennessee, Arkansas, Virginia, and North Carolina. Soybean in the mid-southern U.S. already suffers yield loss from the native heliothine species Helicoverpa zea, and establishment of H. armigera could increase management costs. When compared to H. zea, H. armigera has more cases of documented insecticide resistance, feeds more aggressively on soybean, and occurs earlier in the season, with potential for more generations per cropping cycle. These biological attributes suggest that H. armigera could be more damaging to U.S. soybean than H. zea.
The invasive H. armigera and the native H. zea are closely related and considered sibling species with potential for interbreeding. Hybridization between the two species has been documented under field conditions in Brazil. This could have important ecological and pest management implications for soybean and other crops. The two species have been geographically separated until the recent introduction of H. armigera to the western hemisphere.
In Brazil, H. armigera is currently managed using Bacillus thuringiensis (Bt) insecticidal protein traits in soybean and insecticide applications. If it establishes in the U.S., correct species identification will be key to devising sound management strategies, which is challenging because H. armigera is phenotypically indistinguishable from H. zea. Some insecticides that are effective for control of H. zea may not be effective against H. armigera due to insecticide resistance.
A sustainable pest management solution to managing H. armigera is to utilize all available pest management tactics. Being prepared for yet another heliothine species in the U.S. requires correct species identification, monitoring and early detection, and understanding susceptibility of populations to available control tactics.
Journal of Integrated Pest Management
Fikru Haile, Ph.D., is a trait program scientist at Corteva Agriscience. Email: firstname.lastname@example.org. Tim Nowatzki, Ph.D., BCE, is global biology leader at Corteva Agriscience. Email: email@example.com. Nick Storer, Ph.D., is global seeds regulatory advocacy leader at Corteva Agriscience. Email: firstname.lastname@example.org.