Oxitec today announced that two of its agricultural product strains have now completed the first phase of developmental testing and the company is now seeking to work with third parties to evaluate the strains in different countries under appropriate regulatory oversight.
The Olive fly (Bactrocera oleae) is the single major pest of olives, causing major crop damage and economic loss and is not well controlled by current methods. Insecticide resistance and the withdrawal of older more environmentally unacceptable insecticides are currently exacerbating the problem, increasing both crop losses and the cost of control.
The Mediterranean fruit fly (‘Medfly’, Ceratitis capitata) is a global pest and attacks over 300 types of fruits, vegetables and nuts worldwide. Current control measures include insecticides, mass trapping and lures. In some countries, such as the USA, the radiation-based sterile insect technique (SIT) has been used successfully to reduce infestations to near zero levels. Oxitec’s RIDL technology has been designed to improve upon the scope, cost efficiency and flexibility of SIT across a wide range of insect species.
In many insect species (including Olive fly and Medfly) it is the female that causes damage to the crop through depositing their eggs into the fruit. Oxitec’s solution harnesses advanced genetics to be able to release ‘sterile’1 male insects that mate with wild females of the same species. The genetic modification prevents females in the next generation from surviving to adulthood and hence reproducing. Successive releases of these ‘sterile’ males, depending on the control strategy adopted, would result in either the prevention of a seasonal build-up of the insect pest or an area-wide target pest population decline.
Oxitec have now completed a suite of laboratory based tests of its RIDL® Medfly OX3864A and Olive fly OX3097D product strains. Both strains successfully met internal target profiles including genetic sex specificity, bright dominant fluorescent marking and genetic sterility from the female-specific transgene. Laboratory testing under simulated mass-rearing conditions shows that the transgenes have no significant negative effects on productivity which should indicate an efficient cost of production. Furthermore, from greenhouse-based sexual competition tests Oxitec males are equally as competitive as wild-type males. Studies also indicate similar behaviours of the Oxitec males compared to the wild-type males. Both of the product strains have been shown in contained trials to be able to eliminate an established pest target population.
Commenting on the development Dr Martha Koukidou, who heads Oxitec ‘s Fruit Fly programme, said; ‘Medfly and Olive fly are major agricultural pests where farmers need new environmentally friendly control solutions. We are delighted our strains have performed so well and we think both are highly promising product candidates. Over the past few years we have had many enquires to evaluate these strains in countries where agricultural production is severely affected but until now we had not completed our in-house testing. But we have now reached the point where we can make these available to third parties under appropriate regulatory supervision for in–country testing’.
The next stage of development for these strains will depend upon potential use within a country, the collaborating partner, stakeholder engagement and appropriate regulatory processes but would include a series of step-by-step trials to establish efficacy, safety and environmental impact.
About the Sterile insect Technique
The Sterile Insect Technique, using radiation as a sterilisation method, is based on the mass-rearing and release of a large number of sterile insects to the field and their subsequent mating with the native pest population. The technique is species-specific and environmentally-friendly. The technique has successfully been used to eradicate the Screw-worm fly (Cochliomyia hominivorax) in areas of North America. There have also been successes in controlling species of fruit flies, most particularly the Medfly (Ceratitis capitata), and the Mexican fruit fly (Anastrepha ludens). Insects are sterilized with radiation, which can weaken the insects, making them less able to compete with wild males. With most radiation based forms of SIT the sexes cannot be separated so females are co-released with males.
Note 1. In the case of Oxitec’s RIDL® approach the insects are not strictly sterile, rather they are capable of mating but progeny of the matings between the Oxitec insects and wild insects are nonviable. In this case the lethal effect is female specific, so that only the female progeny die
About Oxitec (www.oxitec.com)
Oxitec is a British company pioneering a new approach to combating insects that spread disease and damage crops. The Oxitec solution harnesses advanced genetics to create ‘sterile’ male insects to mate with females of the same species resulting in a population decline. Oxitec’s approach to insect control has been demonstrated in mosquitoes in open field trials in Cayman and Brazil. Oxitec has a portfolio of strains for use in public health and agriculture
For further information contact
Dr Martha Koukidou +44 1235 832393