Fall armyworm (FAW) (Spodoptera frugiperda) is a serious pest in corn, if uncontrolled; this pest can cause a severe damage of the breeding materials of the seed industry at Puerto Rico. One of the tools to manage FAW is the use of insecticides of different modes of action. However, FAW has a tremendous ability to develop resistance. Therefore, monitoring the susceptibility or resistance of FAW to insecticides is critical to establish a successful insecticide resistance management plan (IRM). Monitoring of resistance requires the knowledge of specific methods of insecticide bioassays and analysis of data. Consequently, Michigan State University, IRAC International, and Corteva Agriscience in partnership with PRABIA offered a training course in methods of bioassays for FAW.
The training consisted of classroom training and hands-on laboratory and field experience and reviewed concepts associated with insecticide mode of action and resistance to synthetic compounds. A review of the theory and practice of laboratory bioassays methods for detection of insecticide resistance including leaf disc (IRAC Method No. 007) and insecticide incorporated diet (IRAC Method No. 020) was performed by the participants. In addition, evaluation of the larval mortality was performed by the participants of this training. Probit procedure from SAS and/or POLO program were used to analyze mortality data of the laboratory bioassays, and results of the data analysis were discussed.
