Many stakeholders and scientists presented from Plant and Food Research, Scion, Auckland Uni, Otago Uni, Massey Uni, Lincoln Uni, DOC, Councils and committees. New science and efforts made to further the understanding of Kauri dieback and the management thereof were covered.
The Kauri phytophthora strain has been scientifically identified as new and officially renamed Phytophthora agathadicida, still referred to as PTA.
What is now better known about this pathogen:
- It is soil borne, meaning it is introduced to Kauri (Agathis australis) via the fine roots nearer the soils surface, in which it travels up through the vascular tissue of the tree. Trees may not always be symptomatic that are infected!
- It is transferred to new territories in soil particles, including but not limited to human footwear, feral pigs and fauna, tracks and tires, machinery with soil attached, and nursery plants.
- In all of the research so far, there have been no identified Kauri trees that demonstrate any resistance to the pathogen- scientists are hoping to find a few eventually with natural resistance, no such luck thus far.
- Phytophthora has the ability to be introduced to a new soil environment by dormant microscopic oospores, which can be viable for an unknown period of time in the environment, or by zoospores which are motile in the soil via water.
- Consider all kauri material as contaminated when working in regions with known PTA, such as Titirangi and the Waitakeres.
- Sanitation of footwear: Removal of all soil particles and disinfecting with Trigene should occur for everyone when walking around Kauri trees, even if the work is being done on a tree neighbouring a kauri.
- Sanitation of tools: Clean and remove all soil particles from saws and equipment, then disinfect with Trigene.
- Sanitation of large equipment that leaves the road: If tires or tracks operate off of paved or road areas within PTA areas, removal of the soil from tracks and tread must occur. Where this is not practical, may want to reconsider work methods or bring a brush for cleaning large equipment and acknowledge the time it will require.
- All Kauri branch, stem, wood, foliage material: Preferable to leave on site! If it must be removed, don't chip. If a chipper is contaminated it becomes a much larger issue to clean. If mulch is created, it may harbour spores which can further be spread via the mulch product, it may not die or decompose in the mulch pile at temps.
- It is much preferred to leave tree material in whole branch and stem form to minimize spread. Furthermore, if it is moved off site, burning may be the only method to remove the pathogen spores from circulation.
By Erika Commers