Diamondback moth

Why we need a solution to the diamondback moth pest

The diamondback moth is one of the world’s most significant agricultural pests, costing farmers billions of dollars every year. This moth pest, scientific name Plutella xylostella, is a non-native species in the United States. It feeds on brassica crops including cabbage, cauliflower and broccoli, and it is well-known for its ability to develop resistance to synthetic and organic insecticides. New control methods for the diamondback moth are needed that are effective, sustainable and do not disrupt environmentally sensitive species like pollinators.

Benefits of Oxitec’s approach

Oxitec is a pioneer in insect pest control with an approach that is both effective and environmentally sustainable. We genetically engineer insects to use them as a tool to control populations of their own species.

Studies in the lab and greenhouse cages have shown that Oxitec diamondback moths can be very effective at reducing pest diamondback moth populations.

The approach is toxin-beneficial insectfree and is specific to the diamondback moth so does not affect beneficial insects, including pollinators and natural predators of pest populations.

The male moths only mate with females from their own species so the genes won’t spread to other populations. Additionally, the insects die out so the released insects and their genes do not persist in the environment.

How does Oxitec’s self-limiting approach work?

Oxitec male moths pass on a pest control (or ‘self-limiting’) gene that prevents their female offspring from reaching adulthood. This reduces the number of females able to reproduce and the pest population in the release area shrinks. The Oxitec diamondback moths also have a fluorescent protein marker (DsRed2) that distinguishes them from wild pest moths. This colour marker is used to track and monitor the moths in the rearing facility and in the field.

Oxitec’s approach requires successive releases of males to effect population control. Because the diamondback moth is engineered to be self-limiting in the environment, once releases are stopped, aside from the intended effect of supressing the pest diamondback moth population, the release site returns to its pre-release condition. As the approach is species-specific, impacting only the pest diamondback moth population, it has the benefit of avoiding the off-target effects associated with conventional and organic chemical controls. Additionally, the release of the male moths does not contribute directly to yield losses, as it is the caterpillars from eggs laid by the females that are responsible for damaging crops.

Have there been outdoor releases of genetically engineered insects?

Regulated environmental releases of genetically engineered (GE) mosquitoes (Aedes aegypti OX513A) have been taking place since 2009, with more than 150 million engineered mosquitoes released worldwide. Aedes aegypti is the mosquito species that spreads serious viral diseases of humans such as Zika, dengue and chikungunya.

In all efficacy trials completed to date the Oxitec self-limiting approach has reduced target Aedes aegypti populations by more than 90%, which is an unprecedented level of control (world-leading mosquito control groups using best available methods can only reduce the Aedes aegypti population by up to 50%). Releases in urban environments have taken place in Cayman, Brazil, and Panama and more are being planned. In the US, the Food and Drug Administration (FDA) recently announced a final Finding of No Significant Impact for Oxitec’s GE mosquito for a proposed trial in the Florida Keys. This decision was based on a comprehensive environmental assessment submitted by Oxitec and concluded that the environmental release of the GE mosquitoes would not result in a significant impact on the environment, including humans.

Next steps

The Oxitec diamondback moth has been evaluated in lab and greenhouse studies in the United Kingdom and the US, and in 2015 in-field cage experiments at the Cornell University College of Agriculture and Life Sciences Agriculture Experiment Station in Geneva, NY. The first open field trials are also being considered at the Agriculture Experiment Station pending Federal (USDA-APHIS) and New York State approvals. Because of this there is currently no set timeline for the release. More information will be available as these processes develop.

Questions about the trials or the technology can be directed to: dbmtrial@oxitec.com

For more information on these trials, please visit the Cornell University website here: http://shelton.entomology.cornell.edu/diamondbackmoth/