Project Overview

Reports

Commodities

• Agronomic: corn

Target Pests

Practices

   Corn is the primary feed grain in the U.S., making up more than 95% of corn production and use (USDA ERS 2024). Most U.S. corn is produced in the heartland, whose southernmost region lies in northern Oklahoma. During the 2024 corn season, an outbreak of the corn leafhopper (CLH), Dalbulus maidis (Hemiptera: Cicadellidae), was reported in Oklahoma, Texas, Kansas, and Missouri. Likewise, symptoms of corn stunt (CS) disease were observed in several states in the Southern, Great Plains, Corn Belt, and Northeastern regions. In addition, the main pathogen associated with CS (Spiroplasma kunkelii) was molecularly characterized in Oklahoma, Missouri, Arkansas, Kansas, Nebraska, South Dakota, Wisconsin, Minnesota, New York, Indiana, and Texas. The CLH is an invasive insect from Mexico and is the most important and widespread economic pest affecting corn production in Latin America. The insect is a dual threat due to the direct injury it causes by feeding on the plant and its ability to vector multiple pathogens associated with CS. For years, this pathosystem was considered of secondary importance in corn-producing regions in the Americas, but since 2015, it has re-emerged as a major threat. This year was not the first time corn production areas in the U.S. have seen CLH and CS. However, the insect's re-emergence and expanded incursion into the Great Plains and Corn Belt states could have severe economic consequences for corn production should this pest become established.

   Despite the significant threat this pathosystem poses to corn production, information on the temporal and spatial dynamics of these pests in the U.S. remains limited. The CLH’s ability to migrate long distances and rapidly establish itself in new environments makes isolated management efforts among growers and stakeholders insufficient for effective pest control and preventing yield losses. Since the CLH efficiently transmits CS pathogens and no curative measures exist for this disease, control programs rely on detecting the insect's presence in corn fields rather than economic thresholds. As a result, growers are encouraged to apply insecticides immediately upon CLH detection. Therefore, monitoring for and alerting to the CLH’s presence is imperative.

   Establishing a network for monitoring and developing regional management tools for the CLH and CS throughout the U.S. Southern, Great Plains, and Corn Belt states is needed. A multidisciplinary team of scientists, including plant pathologists and entomologists, from multiple land-grant universities across the U.S. (OK, MO, TX, LA, AR, KS, NE, SD, IA, WI, IN, IL, KY, TN, AL, NY, NM and MN) will monitor the CLH and CS symptoms through the 2025 growing season. Data on CLH abundance and CS symptoms in each state will be reported using the EDDMapS (https://www.eddmaps.org/) and Corn Stunt Map – as a new product of Corn ipmPIPE (https://corn.ipmpipe.org/). The goal is to leverage existing IPM networks and resources that researchers are familiar with to maximize and reduce duplication of efforts. Establishing a working group will facilitate opportunities for scientists to develop or optimize protocols that allow further studies on insect and CS pathogens detection, research on the ecology and genetics of these pests, and data sharing and knowledge exchange.

   The proposed research will result in a robust dataset regarding the temporal and spatial dynamic of the CLH and CS presumptive symptoms in the U.S. Such data is fundamental to assessing the risk of those pests and collaboratively developing decision-making aids, management tools, and extension education initiatives. Furthermore, the data will be leveraged for additional funding opportunities, expanding the scope of work that directly benefits corn producers. Implementing the developed tools will maximize the efficacy of management decisions, reduce pest-related yield losses, and ensure corn remains a viable U.S. economic crop.

• Establish a network of collaborators from multiple universities across the major U.S. corn-producing regions.
• Monitor the spatial and temporal dynamics of the corn leafhopper and corn stunt in the U.S.
• Determine the overwintering capability of the corn leafhopper in the southern U.S. states.