Self-limiting fall armyworm: a new approach in development for sustainable crop protection and resistance management

Abstract

Background The fall armyworm, Spodoptera frugiperda, is a significant and widespread pest of maize, sorghum, rice, and other economically important crops. Successful management of this caterpillar pest has historically relied upon application of synthetic insecticides and through cultivation of genetically engineered crops expressing insecticidal proteins (Bt crops). Fall armyworm has, however, developed resistance to both synthetic insecticides and Bt crops, which risks undermining the benefits delivered by these important crop protection tools. Previous modelling and empirical studies have demonstrated that releases of insecticide- or Bt-susceptible insects genetically modified to express conditional female mortality can both dilute insecticide resistance and suppress pest populations. Results Here, we describe the first germline transformation of the fall armyworm and the development of a genetically engineered male-selecting self-limiting strain, OX5382G, which exhibits complete female mortality in the absence of an additive in the larval diet. Laboratory experiments showed that males of this strain are competitive against wild-type males for copulations with wild-type females, and that the OX5382G self-limiting transgene declines rapidly to extinction in closed populations following the cessation of OX5382G male releases. Population models simulating the release of OX5382G males in tandem with Bt crops and non-Bt ‘refuge’ crops show that OX5382G releases can suppress fall armyworm populations and delay the spread of resistance to insecticidal proteins. Conclusions This article describes the development of self-limiting fall armyworm designed to control this pest by suppressing pest populations, and population models that demonstrate its potential as a highly effective method of managing resistance to Bt crops in pest fall armyworm populations. Our results provide early promise for a potentially valuable future addition to integrated pest management strategies for fall armyworm and other pests for which resistance to existing crop protection measures results in damage to crops and impedes sustainable agriculture.

Invasiveness, biology, ecology, and management of the fall armyworm, Spodoptera frugiperda

“…However, the key to long-term efficacy of any transgenic crop against FAW is using it in conjunction with other tactics as part of integrated pest management (Van den Berg et al 2021b). A promising new tactic that has the potential to increase sustainability of Bt crops is to release susceptible, self-limiting FAW (Reavey et al 2022). 5.9.3 Maize landraces and wild ancestors as resistance sources Crop landraces and crop wild relatives are subjects of increasing research to uncover traits and strategies to improve stress tolerance in crops in the face of climate change.…”

Trends towards Lower Susceptibility of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Teflubenzuron in Brazil: An Evidence for Field-Evolved Resistance

“…One of the strategies to manage insecticide resistance is the rotation of insecticides that do not show cross or multiple resistance between each other within or between different modes of action (MoA) [ 28 , 44 ]. The use of IPM measures is essential as well, we can point out the use of Bt crops, selective insecticides to keep natural enemies and to be used together with biological control with macro and microorganisms, mating disruption with pheromones and transgenic S. frugiperda individuals with self-limiting gene [ 8 , 45 , 46 , 47 , 48 , 49 ].…”

Co‐CRISPR: A valuable toolkit for mutation enrichment in the gene editing of Spodoptera frugiperda

“…The available genetic information would promote the development of new pest control strategies (Reavey et al. , 2022). However, in most reverse genetic research, the gene knockout mutants will not display obvious phenotypes that would lead to extra labor for the identification of mutants and screening of homozygous strains (Wang et al.…”