International Advances on Pesticide Application
For the first time in many years, there was a small session on aerial applications - Recently, this has been a very minor part of the proceedings. There were two papers on spraying from the air, using what we would call drones, or UAVs, one from the USA and one from China. Ken Giles (University of Davis, California) explained that in the USA the terminology ‘Remotely Piloted Aircraft’ is used in order to emphasise – to regulators in particular - that there is still someone responsible for the vehicle and the pesticide application. This seems something that might be sensible to take note of in the UK if we want to adopt this technology. The broad conclusion from the papers seemed to be that while there may be a role for ‘RPA’ spraying, its main benefit is likely to be in replacing knapsack spraying where operator exposure is an issue
A session on standards and training highlighted some of the issues with standards – Emilio Gil (Catalonia University) showed how many person-hours and how much water is required to test an orchard sprayer. 88 hours and almost 20 000 L of water was needed, much of it containing copper oxychloride. This is a problem in regions where water is scarce, and a problem everywhere for responsible disposal. Matthew Horne of Bedford College undertook an exercise in testing commercially-available knapsack sprayers in the UK and found that none complied fully with the standard, with all of them failing on provision of information.
Spray drift remained a huge topic on the agenda with field and wind tunnel measurement techniques being discussed, and exposure assessments for residents and bystanders, non-target terrestrial plants and surface water under consideration. The problem of optimising pesticide performance with minimising spray drift remains, with a number of papers attempting to find ways of balancing these competing demands, particularly looking at tunnel sprayers in orchards where the challenges are greatest, and ‘old’ innovations such as Droplegs for arable crops. A decision-support system to balance efficacy and drift, under development in Australia, was presented by Andrew Hewitt although the data required for the underlying models seems immense and at this stage, not necessarily practical.
Adjuvants are clearly an important topic in South America, with a number of papers from Brazil looking at how adjuvants affect all parts of the performance of pesticide sprays. The question of why use adjuvants to control drift when there are nozzles which can do the same job was asked of Ulisses Antuniassi of Sao Paolo State University, who responded that there is a limit to the spray drift reduction that can be achieved with nozzles alone and therefore the combination of nozzle and spray liquid is likely to be needed to deliver the level of spray drift control that is now demanded of regulators.
There was a surprisingly small session on variable rate application, given how much discussion this topic has in the UK. A paper by Peter Jensen of Aarhus University summarised research undertaken to develop the theory that a constant pesticide dose per leaf area or crop biomass will optimise efficacy. This was tested on potato late blight, foliar diseases in winter wheat and desiccation of potatoes and found to be valid for two of the three cases. You will need to read the paper to discover which ones!
The real highlight of the conference was the talk given by UK spray operator Iain Robertson. Iain was 2007 Farm Spray Operator of the Year and is currently on the NRoSO board. His presentation ‘A Season in the Life of a Spray operator’ gave a much-needed insight into the day-to-day pressures of doing the job of pesticide application, and I am sure made many of us more ‘nerdy’ researchers felt that much of our research seemed rather irrelevant. His two messages – ‘Proper Preparation Prevents Poor Performance’ and ‘Keep it Simple, Stupid’ showed that all of those involved in developing ‘best practice’, guidance or labels might need to think again!
The AAB IAPA conference is one of the best, or possibly even the best, for pesticide application world-wide. It is a great opportunity for networking and there is a good mixture of old hands as well as new blood. Antonio Fuentes from the University of Cordoba won the Per Gummer Anderson Award for early career researchers for his paper on reducing spray drift by adapting the spraying equipment to the canopy shape in olive orchards with isolated trees – many congratulations to him for a good paper that was well presented.
Copies of the proceedings can be obtained following the link.