What motivated you to conduct this latest round of spray research? What is it about this subject that continues to capture your interest?
It’s not so much spray application research that motivates me – it is more the challenge of maintaining effective disease and pest control and market access programmes in an increasingly complex world.
I keep coming back to spray application work because I find it is often a weak link in pest and disease control programmes.
Spray application has always been something of a black art – the outcomes from individual spray applications are usually not visible quickly enough to detect and correct potential errors and inefficiencies.
This, combined with the fact that there are so many variables in the spray application process, means that spraying practices are usually quite conservative. It also means that there are significant opportunities to improve spraying outcomes and efficiency.
What was something surprising during this most recent tranche of research? (This could be either during the research period or from the results)
Spraying should never be seen as the sole fix for a problem, and agrichemical application must be supported by other controls in truly integrated management programmes. The most exciting part of my work in the Smart & Sustainable research programme to date has been the re-invigoration of orchard floor sanitation practices as key tools to reduce pathogen inoculum pressure on fungicide spray programmes.
What was something challenging that you encountered during the research?
As part of our work in the Smart & Sustainable project we have been trying to address the “too many variables” problems of sprayer setup and operation.
Depressingly, around half of the sprayers and spraying practices in any crop we have looked at around the world (and New Zealand is no exception to this) are in some way compromised by different combinations of negative interactions between the many variables involved in spraying. And yet agrichemical spray programmes usually work to achieve effective pest and disease control – it amazes me that they work as well as they do.
The opportunity here is an extension one – we need tools to detect and correct spraying faults and inefficiencies. If we can do that, the opportunity to do better is very real and, potentially, to do it with less chemical use.
When did you begin working within horticulture research? Can you please give us a brief summary of your experience/how you ended up here.
I started work as a plant pathologist with MAF Tech in Hawke’s Bay way back in 1989 after I completing a Masters in pest and disease management at Lincoln University. I fell into spray application research a few years after that, largely because I kept finding spraying weak links in control programmes.
Have you always been interested in plant/spray research?
Weirdly yes – my parents established a stone fruit orchard in the Bay of Plenty as a retirement plan when I was doing a Hort Science degree at Massey. We initially handgun sprayed about 3ha of trees and only used about 250 l/ha of spray to do this on three-year-old trees. Then we bought an airblast sprayer and were told we need to apply at least 1000 l/ha to do the same job. That kind of messed with my head!
What’s been the most interesting piece of research you’ve completed to date?
I think that being part of the team that developed the apple Integrated Fruit Production programme back in the 1990s stands out. As part of that work, I was involved in helping establish the weather station network and had input into the disease models that we still use. Spray application came into that work too – with a challenge from Les Anstis (then New Zealand’s only professional sprayer calibrator) to come up with a method for describing different tree canopies as spraying targets.