Why are biopesticide trials so difficult?

Updated: Mar 24

Biopesticide trials can be difficult. But it is worth persevering and gaining a solid understanding of the peculiarities of using biological technologies in integrated pest management. "Don't get frustrated when your trials don't seem to be working like you want them to", says Dr Roma Gywnn, "Bioprotectants all have multiple modes of action on target pests and multi-interactions with plants and this is much of the reason behind the difficulties we encounter in biopesticide trials." Dr Gwynn gave a 90-minute master-class on the fundamentals of efficacy and data interpretation in Session 4 of the ASEAN Fall Armyworm Action Plan Biocontrol Workshop series. One key lesson is that laboratory efficacy does not equal field efficacy. In this case, Dr Gwynn advises, "You need to get out of the lab and either use small pot trials or better still, get into the field." Efficacy is always a complex part of trials and you need to take into account what you are trying to achieve and a variety of factors. Taking the time to understand this from the start is important. A list of such factors to consider was provided in the presentation. Dr Gwynn also explored the difficulties encountered in analysing the data collected in field trials and warned that expecting a consistent dose curve was unrealistic given the significant variation one encounters when using biopesticides, "You have multiply variance in the living system, in the target population and the biopesticide population, all of which has a multiplier effect." This explains why data variation can be as high as 40% in biopesticide trials compared to a much smaller variation of around 8% when trialling conventional chemistries. When discussing your results it is important to show a good understanding of what is happening with the pest, the product, and what is happening with the plant. "Don't forget to share your thoughts on your failures also", says, Dr Gwynn. "We learn a great deal through sharing information on what hasn't worked". The session can be downloaded from our videos page at www.aseanfawaction.org. Join the forum section on biocontrol to share your thoughts. What are your failures and successes with biopesticide trials? How can biopesticides be part of an integrated pest management (IPM) approach?