Exosect advances in microbial delivery with sprayable formulation of virus

Exosect Ltd, a pioneer in Lean Formulation Technology™, has released positive interim results from its virus formulation development programme which is seeking to overcome the formulation challenges associated with virus delivery in agriculture.

A great deal of research is currently underway on the use of viruses for the benefit of food production with examples ranging from the delivery of beneficial viruses (bacteriophages) to animal feed as an alternative to antibiotics, to the use of viruses as delivery vehicles for the application of RNAi molecules to seeds or foliage for crop protection.  Scientists at Exosect’s UK based R&D facility have been developing a novel formulation of a baculovirus, a category of virus which is routinely used against lepidopteran pests in agriculture, using their proprietary formulation platform, Entostat®.

The virus formulation challenge

Baculoviruses, have been successfully used to control a number of economically important pests, including caterpillars, sawflies and beetles. They have an extremely positive environmental profile as they are highly specific, leave zero residues, can be applied up to the day of harvest and have re-entry intervals of a matter of hours. In spite of this their uptake has remained somewhat limited due to several drawbacks; they are highly sensitive to ultra violet degradation with significant reductions in efficacy observed within 4 to 24 hours of application in full temperate sunlight.  As such, applications need to be precisely timed and repeated applications are often required to achieve control of multiple generations which makes their application more expensive and time consuming to the grower.

Exosect has developed a novel sprayable formulation of a baculovirus which controls the destructive lepidopteran pest, Spodoptera littoralis (African Cotton Leaf Worm).  Initial studies confirmed that the Entostat encapsulated virus suffers no impairment through the formulation process. The latest studies have revealed that formulation using Entostat enables a fifty percent reduction in the amount of virus required to match the treated control.
 
Working with experts in the field of insect viruses, Professor Kenneth Wilson of the Lancaster Environment Centre at Lancaster University and Principal Scientist David Grzywacz of the Natural Resource Institute at the University of Greenwich, the next steps for the programme include testing the novel virus formulation for ultra violet (UV) stability.

Exosect’s Chief Technology Officer, Dr. Aoife Dillon, comments, “The data shows that the Entostat formulation is successfully delivering the virus to the insect gut.  The next phase is to test the extent to which Entostat can provide UV stability to the virus”.

Exosect CEO, Andrew MacNaughton comments, “Novel formulations can provide a significant competitive advantage, this is especially true when formulating microbial active ingredients where patenting a specific virus or isolate of a bacteria or fungus is fraught with complications.  In this situation, Exosect’s wide patent portfolio surrounding the delivery of active ingredients to targets offers licensees the opportunity to generate further intellectual property around the formulation itself”.

An update on this project will be presented at the Society for Invertebrate Pathology (SIP) conference in San Diego, USA from 13-17 August 2017 by Exosect’s Researcher, Freya Scoates.  

Entostat is a proprietary micro-powder, based on natural and/or synthetic waxes and has electrostatic properties. It is a lean formulation delivery platform for a wide range of synthetic and biological active ingredients.  It enables a significant reduction of synthetic active ingredient with equivalent or improved efficacy. For microbial organisms, Entostat can provide various benefits such as higher loading, increased longevity and uniformity in delivery.   Importantly, the constituents of Entostat are listed on FIFRA 25(b)1 list of inert ingredients that can be used in pesticide products that are exempt from regulation.