Recipient Organization
OHIO STATE UNIVERSITY
1680 MADISON AVENUE
WOOSTER,OH 44691
Performing Department
(N/A)
Non Technical Summary
The fall armyworm outbreak of 2021 decimated many acres of alfalfa and forage grasses across the U.S., especially in the Eastern cornbelt. Although rare, a fall armyworm outbreak may occur with increasing frequency, since their migration, distribution and development are associated with weather and climate conditions. Yet we lack recent research on 1) fall armyworm development in alfalfa exposed to natural temperatures, 2) insecticide efficacy in alfalfa and forage, 3) the impact of autumn defoliation on wintering stress, 4) the relationship between climate changes and FAW pressure. Furthermore, extension specialists need a foundation of information and tools to help provide recommendations to producers, including how these practices may be influence by changing climates. We will combine expertise among entomologists, agronomists and climatology to research the impact of fall armyworm on alfalfa and forage, as well as to develop and deliver extension information to our stakeholders. We will use a combination of laboratory, greenhouse and field trials along with a variety of extension delivery mechanisms (3D printing, videos and hands-on workshops) to improve fall armyworm management. While we likely cannot prevent the next fall armyworm outbreak, our goal is to prepare alfalfa and forage producers and other stakeholders so that repeated outbreaks have minimal impacts on production.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Goals / Objectives
The fall armyworm outbreak of 2021 decimated many acres of alfalfa and forage grasses across the U.S., especially in the Eastern cornbelt. We will combine expertise among entomologists, agronomists and climatology to research the impact of fall armyworm on alfalfa and forages, as well as to develop and deliver extension information to our stakeholders. We will use a combination of laboratory, greenhouse and field trials along with a variety of extension delivery mechanisms (3D printing, videos and hands-on workshops) to improve fall armyworm management. Our specific objectives are:Revise FAW development and life cycles that reflect a range of temperatures typical of Eastern Corn Belt autumns.Compare alfalfa and forage insecticide efficacies and residuals for control of FAW larvae.Evaluate the impact of FAW defoliation timing and alfalfa stand age and their interaction on alfalfa winter injury and subsequent year productivity.Develop and refine extension and outreach programming to incorporate FAW management.While we likely cannot prevent the next fall armyworm outbreak, our goal is to prepare alfalfa and forage producers and other stakeholders so that repeated outbreaks have minimal impacts on production.
Project Methods
Objective 1. Revise information on FAW development and life cycles to reflect a range of temperatures typical of Eastern Corn Belt autumns. This objective will compare previous lab-based work with our new data on more natural temperatures and develop a better estimation of FAW development in the field. We will perform field bioassays, releasing FAW in alfalfa fields under small cages. We will monitor the cages for two weeks and then collect all remaining larvae to monitor survival and development. Field bioassays will take place in the spring and autumns of each year of the proposal, with temperatures recorded through data loggers. Additionally, we will release fall armyworm in smaller cages, monitoring and recording movement over a shorter time frame to understand on-plant movement. These studies will be complemented with bioassays in growth chambers that mimic oscillating temperatures typical of autumn weather conditions in the Eastern cornbelt.Objective 2. Compare alfalfa and forage insecticide efficacies and residual longevity for control of FAW larvae. Using several labelled insecticides for fall armyworm control in alfalfa and forages, we will evaluate efficacies and residuals. Tests will be performed using all larval instars through glass vial bioassays and sprayed foliage. In addition, we will artificially infest field plots with fall armyworm and test the efficacy of four of the most common insecticides. Both survival estimations and yield comparisons will be performed.Objective 3. Evaluate the how the timing of FAW infestation in alfalfa impacts harvest management, winter injury, and subsequent year productivity. Questions of the 2021 fall armyworm outbreak centered on harvest management of damaged alfalfa or management in infested fields below established action thresholds borrowed from the southern U.S. (i.e., only skeletonized stems remained) to stimulate regrowth, or would that further stress the alfalfa plants and cause winter injury and lower productivity the following year? These questions related to the long-standing recommendation to take the last harvest of alfalfa by early to mid-September to allow time for regrowth and accumulation of nonstructural carbohydrates and protein reserves in the crown and taproots of alfalfa that are used for winter survival and regrowth the subsequent spring. We will perform field trials with seven treatments that vary the cutting and infestation times in the autumn. In the spring, yield will be taken to compare and identify the best management techniques--i.e. whether to cut early or to spray.Objective 4. Develop and evaluate a modeling tool for predicting and assessing FAW outbreaks. Climate change is shifted first frosts and freezes in the Eastern Cornbelt later and later each year. The extended warm periods in the early autumn have the potential to facilitate extra feeding and generations of fall armyworm. We will use historical trapping and climate data to identify trends and patterns of fall armyworm infestations. Trap catches will be compared to wind patterns that may suggest sudden shifts or infestations of fall armyworm. We will use predictive modelling based on these data to develop severity indexes and identify variable most strongly associated with outbreaks.Objective 5. Objective 5. Develop extension programming for FAW management. We will develop several extension deliverables to engage alfalfa and forage stakeholders for improved fall armyworm management. These include 3D printed models (of both fall armyworm and caterpillar sizing tools), extension factsheets, annotated slide sets, presentations at forage conferences, a workshop focused on fall armyworm management in alfalfa and forages, and capstone website, fall armyworm management videos, and fall armyworm pheromone trapping networks.