Improved Orchard Floor Management in Truffle Orchards - Update

The DPIRD/AgriFutures/TPWA funded research project, PRJ013065 Improved Orchard Floor Management is nearing completion.

This project has sought to identify new methods for weed and pest management in the orchard and has for the first time sought to measure the effect of surface treatments on the soil microbiota. Rachelle Johnstone of DPIRD presented the latest information from the project prior to the TPWA AGM.

Over the last 2 years, the team at DPIRD have completed literature reviews, laboratory trials, and field trials to identify and assess sustainable options to improve truffle orchard floor management, focussing on new strategies to control weeds, slaters, and slugs. Weed management trials investigated the use of flame weeding and two organic herbicides – Slasher® (nonanoic acid) and Bioweed® (pine oil) in both young and mature truffle orchards. The alternative treatments were generally not as effective at reducing weed cover when compared to the standard grower practice. However, they have potential to reduce reliance on chemical herbicide if used as part of an integrated weed management strategy.

Root and soil analysis will be completed by March 2024 to assess any impact of these methods on the mycorrhiza and soil biome. Pest management trials included lab and field trials to test several biological based products for controlling slaters including the Entomopathogenic fungi product Velifer® and 3 nematode species. Unfortunately, Velifer® did not demonstrate effective control. The nematodes H. zealandica and H. bacteriophora provided good control of P. scaber but not A. vulgare. Mass trapping of slaters was identified as a potential, non-chemical control method however, field trials of this technique did not provide effective control. Bioassays of the weed treatments found that Bioweed® herbicide was effective at killing slugs and slaters. Slasher® and the flame weeder also killed more slaters (not slugs) than the control. However, weed control in orchards will not likely reduce pests as their sheltering habits protect them from direct contact.

We have updated the Australian Truffle Orchards Integrated Pest and Disease Management (IPDM) Manual to include the latest information to come out of the project. The latest version will soon be available on the DPIRD website.

The project also set out to map the location of all commercial truffle orchards in Australia. The Australian Tree Crop Map now includes 696 hectares (ha) of truffières, with 393 ha (56%) of the plantations in WA,108 ha (15%) in NSW, 101 ha (15%) in Tasmania, and 76 ha (11%) in Victoria. The map can be accessed through the following link www.une.edu.au/webapps

The final report will be completed by April 2024 and will include detailed results from the literature reviews and trials. If you would like further information before then, please contact Rachelle Johnstone at rachelle.johnstone@dpird.wa.gov.au PRJ013065 ‘Improving truffle orchard floor management’ is supported by DPIRD, in collaboration with the Applied Agricultural Remote Sensing Centre, University of New England, and the Australian National University, through funding from AgriFutures Australia as part of its AgriFutures Emerging Industries Program and DPIRD with contribution from Truffle Producers Western Australia Inc