First Field Release of a Genetically Engineered, Self-Limiting Agricultural Pest Insect: Evaluating Its Potential for Future Crop Protection

Abstract

Alternative, biologically-based approaches for pest management are sorely needed and one approach is to use genetically engineered insects. Herein we describe a series of integrated field, laboratory and modeling studies with the diamondback moth, Plutella xylostella, a serious global pest of crucifers. A "self-limiting" strain of Plutella xylostella (OX4319L), genetically engineered to allow the production of male-only cohorts of moths for field releases, was developed as a novel approach to protect crucifer crops. Wild-type females that mate with these self-limiting males will not produce viable female progeny. Our previous greenhouse studies demonstrated that releases of OX4319L males lead to suppression of the target pest population and dilution of insecticide-resistance genes. We report results of the first open-field release of a non-irradiated, genetically engineered self-limiting strain of an agricultural pest insect. In a series of mark-release-recapture field studies with co-releases of adult OX4319L males and wild-type counterparts, the dispersal, persistence and field survival of each strain were measured in a 2.83 ha cabbage field. In most cases, no differences were detected in these parameters. Overall, 97.8% of the wild-type males and 95.4% of the OX4319L males recaptured dispersed <35 m from the release point. The predicted persistence did not differ between strains regardless of release rate. With 95% confidence, 75% of OX4319L males released at a rate of 1,500 could be expected to live between 3.5 and 5.4 days and 95% of these males could be expected to be detected within 25.8-34.9 m from the release point. Moth strain had no effect on field survival but release rate did. Collectively, these results suggest similar field behavior of OX4319L males compared to its wild-type counterpart. Laboratory studies revealed no differences in mating competitiveness or intrinsic growth rates between the strains and small differences in longevity. Using results from these studies, mathematical models were developed that indicate release of OX4319L males Shelton et al. Field Release of GE Insect should offer efficacious pest management of P. xylostella. Further field studies are recommended to demonstrate the potential for this self-limiting P. xylostella to provide pest suppression and resistance management benefits, as was previously demonstrated in greenhouse studies.

Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback mothPlutella xylostella

“…Glasshouse trials have shown that repeated releases of these homozygous males can result in eradication of caged wild-type populations and, additionally, delay evolution of Bt resistance (8,9), a finding in agreement with previous modelling (10,11). Wind tunnel experiments have demonstrated that these males retain the ability to locate and respond to female pheromone plumes (12) and open-field trials have shown that these males are able to disperse within a realistic crop setting (13).…”

Genetic Technologies for Sustainable Management of Insect Pests and Disease Vectors

“…There have been numerous field releases of genetically modified insects, although they are only limited to sterile individuals that are not intended to introgress genetic material in the wild population. These include Wolbachia-based programmes for Dengue control in Australia, Asia, and South America [126,127]; sterile males in the malaria vector A. gambiae in Burkina Faso [128,129]; and RIDL systems engineered in the agricultural pests diamondback moth Plutella xylostella in New York [130] and the pink bollworm, Pectinophora gossypiella in Arizona [131], as well as in the Ae. aegypti mosquitoes as a measure against Zika virus outbreaks in the Cayman Island [132,133], Brazil [134], Malasya [135], and Florida [136].…”

Adequacy and sufficiency evaluation of existing EFSA guidelines for the molecular characterisation, environmental risk assessment and post‐market environmental monitoring of genetically modified insects containing engineered gene drives

“…These strains also express the fluorescent protein marker, DsRed, to permit the effective monitoring of the presence of such strains in the field. Recently, a series of open release trials took place in Geneva (NY, USA) with adult male fsRIDL GM diamondback moths (strain OX4319L) and wild-type counterparts to test dispersal, persistence and field survival of the local diamondback moth population in a cabbage field (Shelton et al, 2020). Further open release trials are recommended by Shelton et al (2020) to assess suppression efficacy.…”

“…Recently, a series of open release trials took place in Geneva (NY, USA) with adult male fsRIDL GM diamondback moths (strain OX4319L) and wild-type counterparts to test dispersal, persistence and field survival of the local diamondback moth population in a cabbage field (Shelton et al, 2020). Further open release trials are recommended by Shelton et al (2020) to assess suppression efficacy. Previous glasshouse experiments demonstrated the effectiveness of this approach (Harvey-Samuel et al, 2015).…”