David Hume, AgResearch
Pest and disease pressures continue to rise in New Zealand as new biosecurity incursions occur and new pest issues emerge with a changing climate. Synthetic pesticides are an integral component of controlling these problems in modern, intensive arable farming systems, but it is rapidly becoming apparent that their use is under threat. Pests and diseases are developing resistance to these pesticides, there is the withdrawal of some currently used pesticides and fewer new chemistry pesticides are being developed. In addition, consumers expect agriculture to reduce pesticide use in favour of using more natural, sustainable approaches to producing food and fibre products with less environmental impact. Use of naturally occurring microbes as biopesticides is an avenue to address these issues.
One example of highly successful use of a microbe in New Zealand is in the pastoral industry, where the Epichloë fungal endophyte enhances ryegrass growth and persistence. Over the last four decades, New Zealand researchers, plant breeders, seed producers and pastoral farmers have led the world in developing and widely using selected Epichloë endophyte technology in commerce.
Using this knowledge, a research programme funded by FAR, Grasslanz Technology, GRDC Australia and the New Zealand Government has successfully introduced Epichloë endophytes into cereals with the aim of boosting the plant’s ability to resist pests and diseases, and possibly improve tolerance to climatic stresses such as drought.
To date, the greatest progress has been in ryecorn (Secale cereale), where ‘animal-safe’ endophytes have been introduced from the wild-grass ancestors of modern cereals. These endophytes have successfully colonised the cereal host plant and are transmitted to and store well in grain. Plant selection has been able to improve endophyte transmission to grain and overall compatibility. Endophyte-infected plants have proven to have lower levels of disease and pest damage, and crop yields have been improved relative to endophyte-free plants.
Progress in wheat has been more difficult, due to wheat being self-fertile compared with ryecorn which is an out-crossing species. Nevertheless, this research has achieved several breakthroughs and is now well on the path to delivering a low cost, biologically based approach to counter pest and disease pressures in the cereal industry.
David Hume, Wayne Simpson, Richard Johnson, Alison Popay Anouck de Bonth (AgResearch)
Jo Drummond, Phil Rolston (FAR).