Knowledge for a sustainable world


After working for The Centre for Overseas Pest Control – one of the Natural Resources Institute's parent organisations – at Porton Down from 1979, David Grzywacz joined the University of Greenwich in 1994 as senior scientist and insect pathologist. He became head of the insect pathology research group in 1993 and subsequently head of the sustainable agriculture group in 2003. He served as head of the Agriculture, Health & Environment Department in 2005–06. David is deputy programme leader for the MSc in sustainable environmental management and the MSc in agriculture for sustainable development.

His career highlights over the last five years have included the development of a new biological control for African armyworm (Grzywacz et al 2008) and the first ever publication on the role of Wolbachia in synergising virus infections in insects (Graham et al 2012). Foci have also included providing scientific advice to new companies setting up production of biological pesticides in Kenya, Ghana and Tanzania, as well as advising the governments of Kenya, Ghana and Tanzania (ongoing) on appropriate policies and regulations for registering novel biological pesticides.

David's collaborating academics include Professor Ken Wilson of Lancaster University, Professor Anthony Shelton of Cornell University, Associate Professor Derek Russell of Melbourne University and Professor Jenny Cory of Simon Fraser University.

David Grzywacz's main research interest is biological control of global and emergent insect pests using insect pathogens. This includes the development of pesticides based upon insect viruses as specific and safe alternatives to the use of synthetic chemical pesticides and the development of biologically based crop protection. A more recent focus is how agricultural research can be translated into greater real impact in developing countries.

The major impact of his research has been in the development of commercial biological pesticides based on insect viruses for the control of a number of global pests. This has focused on the control of several global insect crop pests – the pod borer (Helicoverpa armigera), the armyworm species (Sopdoptera exigua, S.litura, S.littoralis and S.exempta) and the diamondback moth (Plutella xylostella). All of these are major global pests, each causing more than $1bn worth of damage per annum, which, in many cases, have become highly resistant to chemical pesticides.

David's work has involved identifying the specific viruses that can kill these pests, selecting and evaluating the best strains for control, developing efficient systems for producing these viruses and determining how best to use the viruses to control the pest. This has then been transferred to companies to enable them to produce and sell virus-based pesticides in place of toxic chemical insecticides. This had led to commercial production of these novel pesticides in India, Thailand, Kenya, South Africa and Tanzania.

The development of novel biological control of African armyworm

The African armyworm is a major migratory pest that is an irruptive and serious pest of cereals and pasture over a large swath of sub-Saharan Africa. Funded by the UK Department for International Development, David Grzywacz led projects from 1997 to 2013 to investigate and develop biological control of this pest through the use of a virus disease specific to the African armyworm. A new control was needed for this pest as the existing control, through the use of broad spectrum chemical insecticides, was no longer considered environmentally acceptable by funding agencies. The aim of the project was to develop, test and evaluate possible non-chemical options, including pathogens and botanical insecticides, then to set up local production in Africa to supply the new control at a cost affordable to poor farmers in Africa. The research was based in Tanzania, where armyworm outbreaks originate in nine out of 10 years before moving on to other countries.

The research identified the virus disease Spodoptera exempta nucleopolyhedrovirus (SpexNPV) as the most promising pathogen, and collected and genetically analysed a number of strains of the virus (Redman et al 2010). Between 1999 and 2005, field trials in Tanzania identified the effective virus application rate and showed that the SpexNPV was as good as chemical insecticide and better than locally available botanical insecticides at controlling armyworm (Grzywacz et al 2008). The trials also showed that SpexNPV could be applied successfully using locally available sprayers on the ground or through aerial spraying. Production techniques for the virus had been identified and optimised by the NRI team (Cherry et al 1998). Laboratory experiments also identified that mixed wild type inoculations of multiple strains were more pathogenic than any single cloned strain of SpexNPV.

Funded by BBSRC, and in collaboration with Professor Ken Wilson at Lancaster University, a study of the ecology of the SpexNPV and armyworm was investigated between 2008 and 2011. This quantified the genetic diversity of SpexNPV and the changes in the strain population during the armyworm outbreak cycle and between cycles. It also revealed that non-pathogenic infection by SpexNPV, in a covert or latent form, was universal in armyworm.

A key new finding was that the presence of the symbiont Wolbachia in outbreak populations correlated with an increase in pathogenic infections and that these lowered the resistance of host insects to SpexNPV, the first published report that Wolbachia infections could synergise virus infections in insects (Graham et al 2012).

In 2010–13, with funding from the DFID Research into Use Programme, David provided technical support for the building of a facility to mass produce SpexNPV as a pesticide by the company Crop Bioscience Solutions of Tanzania that would become operational in 2013.

The development of insect resistant vegetables for use in Africa and Asia

Research by David Grzywacz between 1997 and 2003, with DFID Crop Protection Programme funding, aimed at developing new biological control for the diamondback moth (DBM), plutella xylostella. DBM is the major global pest of brassicas, including cauliflower, cabbage and oilseed rape, and is estimated to cost between $1bn and $3bn per annum in control costs and damage, mainly because it has developed resistance to many conventional pesticides. A variety of biological controls, including pheromones, insect virus and two different entomopathogenic fungi, were developed and evaluated for use in Kenya. The most promising was found to be a granulovirus the Plutella xylostella granulovirus (PlxyGV) (Parnell et al 1997, Grzywacz et al 2004). However, commercial interest in developing this was not forthcoming.

As a result of this work and the expertise developed on DBM, David was invited to join a new project, a private-public research partnership, the Collaboration on Insect Management for Brassicas for Africa and Asia (CIMBAA). Extensive field studies showed that a new plant-based control was needed and would be compatible in most agronomic situations in Africa and Asia (Grzywacz et al 2010).

This EUR10 million collaboration between the universities of Greenwich, Cornell and Melbourne, and Bayer Crop Science, was formed in 2005 to produce insect resistant brassicas. David Grzywacz, alongside Dr D Russell (an NRI colleague at the time), led the public sector partners in this project. This project successfully developed insect-resistant brassicas based on two previously unused Bt genes, CryICa4 and Cry1Ba2, as a more sustainable brassica pest solution during 2004–10. The elite events developed were trialled in India during 2008–10 and successfully controlled DBM and all other caterpillar pests (Kaliaperumal et al 2011). In 2012, a new Australian $2.9 million project to deploy this technology in Asia, Africa and Australasia was initiated.

Identifying the barriers to the adoption of pro-poor biotechnology in developing countries

An issue of research interest to David Grzywacz was how to better translate public funded research into biological pest control so that it created an impact in the developing world. It seemed that much publicly-funded research into the development of new biological controls was not leading to any significant uptake of the knowledge generated, or the appearance of new biological control products. Teaming up with an industry-based consultant who previously worked with in Africa, key issues in the research-product development chain were analysed (Grzywacz et al 2009). This identified a need to improve the focus of research goals to meet the needs of product development and registration. This was achieved through the adoption of research models that are optimised to facilitate the subsequent commercial development of biological pesticides by private sector companies.

Adoption of new commercial biological controls in Africa is also facilitated by the development and adoption of registration systems that can readily register non-chemical pesticides. Few African countries had a pesticide registration system that recognised biopesticides before 2003. David helped the Kenyan authorities develop a new system, adopted as law in 2008. Since then over 35 biopesticide products have been registered. Kenya's horticultural industry has benefitted from new biopesticide products which ensure its exports to EU continue to meet strict pesticide residue standards. David also advised the Ghana Environmental Protection agency on a biopesticides registration system which was adopted. The first commercial BV biopesticide, produced in Kenya, was registered in Ghana in June 2012 with David Grzywacz as technical advisor.

This interest in the infrastructural and policy barriers to new biotechnology encouraged David to join Dr R Bailey of Chatham House, the premier UK policy think tank, in a new project started in 2013 to undertake a policy study to identify the barriers to the adoption of pro-poor biotechnology in developing countries. These results were presented at an international meeting at Chatham House on Food Security in December 2013. This took the form of a comprehensive analysis of international research on agriculture in Africa to identify policies that constrain uptake and identify structures and examples of improved practice in identifying, commissioning and delivering agricultural research. It is likely to generate a number of follow-on studies to apply these general findings to specific areas of research policy and practice by aid donors, research funders and research organisations.

Deputy programme leader, MSc Sustainable Environmental Management Deputy programme leader, MSc Agriculture for Sustainable Development
  • Fellow, Royal Entomological Society
  • Member, Society of Invertebrate Pathologists
  • Reviewer for Biological Control, Journal of Tropical Insect Science, Journal of Pest Science, African Journal of Agricultural Research, Experimental Agriculture, Crop Protection, Pesticide Chemistry and Physiology, Entomological Research, and Journal of Insect Science.
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