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.

• Graham , Robert I., Grzywacz, David, Mushobozi, Wilfred L. and Wilson, Kenneth (2012) Wolbachia in a major African crop pest increases susceptibility to viral disease rather than protects. Ecology Letters, 15 (9). pp. 993-1000. ISSN 1461-023X (Print), 1461-0248 (Online) (doi:10.1111/j.1461-0248.2012.01820.x)
• Redman, Elizabeth M., Wilson, Kenneth, Grzywacz, David and Cory, Jenny S. (2010) High levels of genetic diversity in Spodoptera exempta NPV from Tanzania. Journal of Invertebrate Pathology, 105 (2). pp. 190-193. ISSN 0022-2011 (doi:10.1016/j.jip.2010.06.008)
• Grzywacz, D., Rossbach, A., Rauf, A., Russell, D.A., Srinivasan, R. and Shelton, A.M. (2010) Current control methods for diamondback moth and other brassica insect pests and the prospects for improved management with lepidopteran-resistant Bt vegetable brassicas in Asia and Africa. Crop Protection, 29 (1). pp. 68-79. ISSN 0261-2194 (doi:10.1016/j.cropro.2009.08.009)
• Stevenson, Philip C., D'Cunha, Reju F. and Grzywacz, David (2010) Inactivation of baculovirus by isoflavonoids on chickpea (Cicer arietinum) leaf surfaces reduces the efficacy of nucleopolyhedrovirus against Helicoverpa armigera. Journal of Chemical Ecology, 36 (2). pp. 227-235. ISSN 0098-0331 (Print), 1573-1561 (Online) (doi:10.1007/s10886-010-9748-8)
• Grzywacz, David, Cherry, Andrew and Gwynn, Roma (2009) Biological pesticides for Africa: why has so little of the research undertaken to date resulted in new products to help Africa's poor? Outlooks on Pest Management, 20 (2). pp. 77-81. ISSN 1743-1026 (Print), 1743-1034 (Online) (doi:10.1564/20apr09)
• Wilson, Kenneth, Grzywacz, David and Mushobozi, Wilfred L. (2009) Biological control of armyworm in Africa: pitfalls and solutions. Pesticides News (84). pp. 18-19
• Grzywacz, David, Mushobozi, Wilfred L., Parnell, Mark, Jolliffe, Flavia and Wilson, Kenneth (2008) Evaluation of Spodoptera exempta nucleopolyhedrovirus (SpexNPV) for the field control of African armyworm (Spodoptera exempta) in Tanzania. Crop Protection, 27 (1). pp. 17-24. ISSN 0261-2194 (doi:10.1016/j.cropro.2007.04.005)
• Pande S., Stevenson P C., Narayana Rao J., Neupane R K., Chaudhary R N., Grzywacz D., Baurai V A., and Krishna Kishore G., (2005) Rehabilitation of Chickpea in Nepal through Integrated Management of Botrytis Gray Mold. Plant Disease 89, 12, 1252-1262
• Grzywacz, D., Parnell, D, Kibata , G., Odour G., Ogutu O. O., ,Miano D . and Winstanley. (2004) The development of endemic baculoviruses of Plutella xylostella (diamond back moth DBM) for control of DBM in East Africa. The Management of Diamond Back Moth and other Cruciferous Pests Proceedings forth International Workshop on Diamond Back Moth, Melbourne Ridland P (Ed) pp271-280
• Parnell, M., Oduor, G., Ong'aro, J., Grzywacz, D., Jones, K, A,. and Brown, M., (2002) The strain variation and virulence of granulovirus of diamond back moth (Plutella xylostella) isolated in Kenya. Journal of Invertebrate Pathology. 79, 192-196.
• Cherry, A J Rabindra, R J Parnell, M A. Geetha N, J.S. Kennedy J S , and Grzywacz D (2000) Field evaluation of Helicoverpa armigera nuclear polyhedrovirus formulations for control of the chickpea pod-borer, H. armigera (Hubn.), on chickpea (Cicer arietinum var Shoba) in southern India. Crop Protection 19: 51-60
• Jenkins, N. E. and D. Grzywacz. (2000). Fungal and Viral biopesticides: quality control-assurance of product performance. Biocontrol Science and Technology, 10, 753-777
• Grzywacz,D., K. A. Jones, G. Moawad and A. Cherry. (1998). The in vivo production of Spodoptera littoralis nuclear polyhedrosis virus. Journal Virological Methods 71, (1) 115-122
• Cherry A. J. Parnell M, Grzywacz D, Brown M & Jones K A (1997) The optimization of in vivo nuclear polyhedrosis virus production of Spodoptera exempta (Walker) and Spodoptera exigua (Hubner). Journal of Invertebrate Pathology, 70, 50-58.

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.

• 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.