SFF Project Summary
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| Final Report [PDF 2.44M] | |
| Latest Update | |
| Updated: | 03 October 2008 |
Problem/opportunity:
The phase-out of methyl bromide severely threatens the sustainability of the New Zealand strawberry industry. Strawberry growers are plagued by various soil pest and disease problems, with Phytophthora being the most important. These problems have generally been controlled by methyl bromide fumigation of soil prior to planting, allowing economic strawberry production in most years, though disease outbreaks have still occurred sporadically, particularly in wet years.
However, with the NZ government’s commitment to the Montreal Protocol on ozone depleting chemicals, methyl bromide will not be available for pre-plant soil fumigation of strawberry beds from January 2005, except under ‘critical use exemptions’. It is important to the strawberry industry and to NZ’s reputation as a clean green producer using sustainable practices that the industry is able to adopt alternative practices that are economically and environmentally sustainable.
The pending loss of methyl bromide has exposed deficiencies in current soil management practices and left growers vulnerable to severe losses from soil-borne pests and diseases. A workshop in Auckland in Feb 2004 involving growers and key researchers discussed the current soil management, sterilisation and disease problems. It identified serious issues and problems relating to soil preparation and management, fumigation effectiveness in sub-optimal conditions, and associated chronic disease problems. It was considered that some currently used soil management practices are not sustainable, and in many cases are causing long-term damage to soil structure and potential productivity. Fumigation was less effective than it should have been, in many instances resulting in substantial economic losses.
The loss of methyl bromide highlights the urgent need for the strawberry industry to improve a number of practices and systems to ensure the sustainability of the industry. Deficiencies in alternative fumigants means that more attention must be paid to factors such as soil preparation and condition, general hygiene practices, and protocols for plant propagation and distribution to minimise disease incidence and spread. Loss of methyl bromide also gives an opportunity to look at a shift in practices away from continuous cropping maintained by total reliance on chemical soil fumigants, and a chance to look at more biologically based solutions.
A systematic and holistic approach is needed to address soil disease problems across the strawberry industry, from nursery propagation beds to fruit production beds. Collaboration between growers and a multidisciplinary research team is most likely to give a better understanding of the problems and lead to more sustainable solutions.
Project description:
A multidisciplinary approach is planned involving strawberry growers, plant pathologists, soil specialists and agronomists. The process will be holistic, taking a ‘back to basics’ look at current industry practices, and how processes can be improved to ensure sustained strawberry production even in the absence of methyl bromide. It will build on alternative fumigant trials supported by industry from 1998 to 2002. There will be emphasis on a range of potential management factors and alternatives under the control of growers, and finding ways to implement these rather than relying on methyl bromide. The programme can be divided into seven main headings, though with a high degree of overlap and integration between them:
1. Grower records/diagnostics of soil and disease problems.
2. Investigation of alternative fumigants and soil management practices.
3. Dealing with sub-optimal conditions.
4. Infection sources for key soil-borne diseases.
5. Pre-planting treatments of plants to minimise disease.
6. Improved nursery practices.
7. Communication and information transfer.
Latest Update: March 2007
This year will almost certainly be the final year that methyl bromide (MeBr) is available for pre-plant soil fumigation of New Zealand strawberry beds. In the upcoming season, almost all growers will be using alternatives in part or all of their gardens. For most growers, the most likely alternatives will be either Telone C35TM or straight chloropicrin (Chl). In most trials these two products have provided plant yield and yield close to that possible with methyl bromide, though concerns remain in seasons where soil conditions are sub-optimal.
Assessments of the large alternative fumigant trials at Perry's and Roselea were completed in February 2007. The trial at Perry's investigated fumigants (MeBr/Chl 50:50, chloropicrin and Telone C35) plus untreated controls, together with a half rate MeBr/Chl 50:50 treatment under virtually impermeable film (VIF) plastic. Data are yet to be fully analysed, but preliminary results show that plant vigour and fruit yield with Telone C35 and chloropicrin have been similar to that obtained with methyl bromide. Results also indicate that VIF mulch did enhance fumigant effectiveness, potentially allowing a slight reduction in fumigant rate. All fumigants were well ahead of untreated controls in terms of plant health, vigour and fruit production. There was also a noticeable relationship between the soil condition in different parts of the block and subsequent plant health, regardless of fumigation treatment. In parts of the block with heavier (higher clay content) soils, root health was inferior to that in lighter soil plots, even when plots were fumigated.
In the Roselea trial, various fumigants and non-fumigant treatments were tested, along with untreated controls. Five varieties ('Camarosa', 'Gaviota', 'Pajaro', 'Ventana' and 'Camino Real') were trialed under the various alternative treatments. Soil was excessively wet during soil preparation and fumigation, and this has challenged the fumigant effectiveness. Some plots were also kept excessively wet over the winter and spring months, to simulate poor growing conditions and put further pressure on the various treatments. Data are not yet fully analysed, but preliminary results show some interesting trends. As expected, all non-fumigant treatments are well behind methyl bromide in terms of plant health and fruit yield. Results also show that many of the alternative fumigants have also lagged behind MeBr. This is the first year this has occurred in the Roselea trials, and probably reflects the poor performance of alternative fumigants in sub-optimal soil conditions. There was no obvious difference in response of plots kept excessively wet throughout the winter and spring compared with those subject to ambient conditions. The only alternative treatment that appeared comparable to MeBr/Chl this year was iodomethane. Notably, there was considerable variation in the treatment responses of the different varieties. These rather complex responses will be summarized in the report in June.
A trial testing the effect of pre-plant dipping or post-plant spraying with phosphorous acid has just concluded at Roselea. All six varieties tested ('Camarosa', 'Camino Real' 'Gaviota', 'Pajaro', 'Seascape', and 'Ventana') responded positively to phosphorous acid treatment. On average, pre-planting dips were more effective than post-planting sprays. Compared with untreated controls, dipped plants produced 46% more fruit, and sprayed plants produced 25% more fruit, averaged across all varieties.
Quarterly Report: March 2006
This project is designed to develop and implement alternative soil management practices for the strawberry industry following the loss of methyl bromide. It is a three-year programme, boosted by a Horticulture Australia Grant, enabling expansion of the alternative fumigant work and participation by Victoria Department of Primary Industries scientists.
In December 2004, studies of soil physical condition and plant disease were conducted in Auckland and Waikato gardens. There were no obvious differences in soil structural characteristics between healthy and diseased areas, where the vast majority of diseased plants were diagnosed as infected by Phytophthora cactorum.
In an effort to minimise effects of Phytophthora, a trial was conducted in the 2004/05 season to test pre-planting dips and post-planting sprays with phosphorous acid. Pajaro plants were generally healthier, grew better and produced more fruit when they were dipped and/or sprayed with phosphorous acid (0.2% PA solution). A further trial was planted in May 2005 to test effects on three different varieties, plus effects in unfumigated ground. Pajaro plants responded well to PA treatments but there were indications that Camarosa may be sensitive to PA dips. The trial is being repeated in 2006 with a wider range of varieties (approx. 10). It is important that such treatments are applied only to varieties that respond favourably.
A large trial was established in the Roselea research garden in Havelock North in May 2005, and completed in February 2006. This trial was primarily aimed at testing alternative fumigant and non-fumigant soil treatments. Pre-plant applications included iodomethane (methyl iodide), methyl bromide, chloropicrin, Telone®C35, FumasolTM, mustard oil, urea, compost and an untreated control. Various biological controls were also trialled. These treatments were tested in both good and in sub-optimal soil conditions. The trial tested three varieties (Camarosa, Gaviota and Pajaro) under various alternative fumigant and non-fumigant soil treatments. Results indicated the various fumigants controlled both pathogens and weeds, but other treatments have had minimal effect. Similarly, plant health, vigour and fruit production has been relatively good in all fumigant treatments.
Key findings, averaged across varieties are:
- Methyl bromide, iodomethane and chloropicrin (in good soil only) gave similar fruit yields.
- Telone C35 and chloropicrin (in poor soil conditions) averaged 10 to 15% lower yields.
- Fumasol yielded 24% & 59% less than MeBr in good and poor soil conditions.
- Untreated, urea, compost and mustard oil treatments yielded 40-60% less than MeBr.
- Root health and overall plant health was generally best in methyl bromide, chloropicrin, iodomethane, and Telone C35 treatments. Fumasol lagged slightly behind the other fumigants.
- Responses differed for different varieties, complicating interpretation.
- If soil conditions were poor at fumigation, fruit yields in some treatments were lower compared to fumigation in good soil. This was particularly noticeable in Fumasol and chloropicrin treatments, but was not a factor with methyl bromide or iodomethane. Telone C35 gave mixed results for the different varieties.
- None of the potential biological controls (various Trichodermas and compost tea) tested in sub-plots gave any improvement over the untreated control.
- Initial pathogen kill and destruction of weed seeds showed that all the tested fumigants gave good control of both pathogens and weeds, but other treatments had minimal effect. Counts of weeds in early spring showed a similar response.
- Studies of gas movement in soil following fumigation indicated that iodomethane moves through soil and subsequently disperses much better than Telone C35.
The Roselea garden trial has been re-established in the 2006 season, this time in sub-optimal conditions where soil was much wetter than ideal. This mirrors conditions frequently encountered in commercial gardens, and those most likely to cause failures with some of the alternative treatments. It is important that we determine these weaknesses prior to widespread adoption by growers. Gas movement analyses and pathogen/weed kill assays are currently being undertaken, and results will be presented at the industry research seminars in early July. Five commercial strawberry varieties are being planted to maximise information on the varieties likely to dominate the NZ strawberry industry over the next few years.
A number of growers have trialled alternative treatments such as Telone C35 in part of their gardens in the current season. Such trials are necessary to complement the more formal research trials. All growers are urged to test alternatives in their gardens next season, even if methyl bromide is available. Telone C35 and chloropicrin are the logical products to trial at this stage. Registration of new products such as iodomethane is likely to be a long way off.
A "critical use exemption" has allowed continued use of methyl bromide in the 2005 and 2006 seasons, though at a reduced rate compared to recent years. This exemption may continue into 2007 at a reduced level, though this is yet to be decided by the international panel. The exemption is unlikely to extend beyond 2007.
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Establishing the alternative treatment trial. Roselea, May06 | |
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Untreated control row (left) and row with pre-plant treatment of Telone C35 (right), showing substantially improved growth with Telone C35. This product is a potential replacement for methyl bromide. |
Other progress
Update of the methyl bromide phase-out and an overview of the current SFF programme at the Annual Strawberry Industry Research Meeting in Auckland (June &'05).
Regular (quarterly) reporting of research results to growers.
Newsletter to all growers, updating results and inviting all growers to
participate (Nov. 05, March 06).
Assessment of Phytophthora status in strawberry Elite propagation beds
(June/July 05, Dec 05, March 06).
December 2005
This project is designed to develop and implement alternative soil management practices for the strawberry industry following the loss of methyl bromide. It is a three-year programme, boosted by a Horticulture Australia Grant, enabling expansion of the alternative fumigant work and participation by Victoria Department of Primary Industries scientists.
In December 2004, studies of soil physical condition and plant disease were conducted in Auckland and Waikato gardens. There were no obvious differences in soil structural characteristics between healthy and diseased areas, where the vast majority of diseased plants were diagnosed as infected by Phytophthora cactorum.
In an effort to minimise effects of Phytophthora, a trial was conducted in the 2004/05 season to test pre-planting dips and post-planting sprays with phosphorous acid. Strawberry plants were generally healthier, grew better and produced more fruit when they were dipped and/or sprayed with phosphorous acid (0.2% PA solution). A further trial was planted in May 2005 to test effects on three different varieties, plus effects in unfumigated ground. Final assessments of these plots will be carried out in early February. Commercial garden trials were also planted in the 2005 season.
A large trial was established in the Roselea research garden in Havelock North in May 2005. This trial was primarily aimed at testing alternative fumigant and non-fumigant soil treatments. Pre-plant applications included , iodomethane (methyl iodide), methyl bromide, chloropicrin, Telone®C35, Fumasol, mustard oil, urea, compost and an untreated control. These treatments were tested in both good and in sub-optimal soil conditions. Results indicated the various fumigants controlled both pathogens and weeds, but other treatments have had minimal effect. Similarly, plant health, vigour and fruit production has been good in all fumigant treatments, although preliminary results indicate that MeBr is still slightly superior to the others tested. The non-fumigant treatments lagged well behind the fumigants in plant health and yield, and in some cases were no better than untreated controls.
A "critical use exemption&" has allowed continued use of methyl bromide in the 2005 and 2006 seasons, though at a reduced rate compared to recent years. This exemption may continue into 2007 (at a reduced level), but is unlikely to extend beyond that.
All growers are urged to trial alternative treatments in part of their gardens in the coming season. Such trials are necessary to complement the more formal research trials, which will continue in a similar manner to that outlined above.
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Untreated control row (left) and row with pre-plant treatment of Telone C35 (right), showing substantially improved growth with Telone C35. This product is a potential replacement for methyl bromide. |
Other progress
Update of the methyl bromide phase-out and an overview of the current SFF programme at the Annual Strawberry Industry Research Meeting in Auckland (June 05).
Regular (quarterly) reporting of research results to growers. Newsletter to all growers, updating results and inviting all growers to participate (Nov 05).
Assessment of Phytophthora status in strawberry Elite propagation beds (June/July 05).
Trial established in the Research Garden at Havelock North in May 2005, to determine the effectiveness of chemical treatment at controlling Phytophthora.
September 2005
This is the fifth quarterly report of a project designed to develop and implement alternative soil management practices for the strawberry industry following the loss of methyl bromide. It is a planned three-year programme.
In February 2005, a survey was sent to all growers to help identify common practices, strengths and weaknesses, plus problems and issues around soil management. Approximately 30% of growers responded to the first part of the survey, but as the season has progressed, responses to the latter parts of the survey have dwindled. Growers who participated in earlier parts of the survey will be contacted by mail or phone over the next few weeks to encourage them to complete the survey. Most of the growers who completed the survey have indicated a willingness to participate in field trials next season.
Early indications are that there are no dramatic plant establishment and root disease problems this season. A relatively dry planting season and early winter in the major growing areas may have contributed to this.
The large alternative fumigant trial, in the Roselea research garden in Havelock North, is well established, with preparations currently being made for the coming harvest. Picking is anticipated to commence in early/mid October. Plant vigour and health in all plots will be assessed before harvest. The trial is testing various alternative fumigant and non-fumigant soil treatments, including methyl bromide, chloropicrin, Telone®C35, FumasolÔ, iodomethane (methyl iodide), mustard oil, urea, compost, and untreated controls. The effect of treatments in sub-optimal soil conditions is also being tested in plots that were over-watered before cultivation and fumigation/bed formation. A number of potential biological controls are also being tested in sub-plots within some treatments, and performance of three major varieties (‘Pajaro’, ‘Camarosa’ and ‘Gaviota’) is being assessed in all main plots. Initial pathogen kill and destruction of weed seeds was tested in all main plots, and showed that all the tested fumigants gave good control of both pathogens and weeds, but other treatments had minimal effect. Counts of weeds in early spring showed a similar response. Studies of plant-back time and fumigant movement in the soil have to date indicated that some alternative fumigants need a longer waiting time than was required with methyl bromide.
The new Roselea trial testing phosphorous acid (PA) treatments to control Phytophthora on three varieties (‘Camarosa’, ‘Pajaro’ and ‘Gaviota’) is also well established, with indications already of the benefits of PA treatment. Health assessments of all plants will be made within the next couple of weeks, and the first harvest is expected in early/mid October. The large grower trials in Auckland are progressing well with harvest already commenced. Plant health assessments will be made in October.
Testing of Elite runner beds for Phytophthora was completed in early winter. No Phytophthora was found in any of the Elite bed samples. This is a huge improvement on previous years, where on some occasions a large proportion of samples were infected. In the coming season, testing of runner beds will continue in an attempt to determine how and when Phytophthora enters propagation beds.
Milestones
A table of proposed and achieved milestones follows. In each quarterly report, this table will be updated and any modifications will be highlighted.
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SFF Project Milestones/Deliverables/Reporting Requirements |
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No. |
Due Date |
Milestone/Deliverable |
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1 |
31 July 2004 |
Meeting with growers to outline project, seek collaborators and trial sites, and encourage participation [Achieved]. Newsletter to all growers outlining the project and expectations [Achieved]. |
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2 |
15 Oct. 2004 |
Written progress report to SGNZ for forwarding to SFF [Achieved]. |
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3 |
31 Dec. 2004 |
Complete soil and disease diagnostics of typical and problem sites [first round of sampling achieved]. Complete PA dipping/spray trial, report results to SGNZ for dissemination to all growers [completed]. Meeting/workshop with all runner growers before spring fumigation [part achieved[1]]. Set up runner grower trials [Achieved]. Written progress report to SGNZ for forwarding to SFF [Achieved]. |
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4 |
31 Jan. 2005
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Set protocols for record keeping for 2005 season, design form/diary, distribute to growers [Achieved]. Identify grower trial sites and confirm protocols and plans for 2005 season. Outline and distribute simple protocols and ideas for growers to carry out their own trials [Achieved]. |
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5 |
31 Mar. 2005 |
Written progress report to SGNZ for forwarding to SFF [Achieved]. |
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6 |
30 Jun. 2005 |
Establish trials on multiple grower sites [Achieved]. Establish soil condition/ water content trial at Roselea site [Achieved]. Check Runner and Elite beds for Phytophthora, report and discuss results with runner growers, outline improved practices [Achieved]. Report to growers via newsletter, annual report and workshop and/or Annual Research meeting [Achieved]. |
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7 |
30 Sep. 2005 |
Written progress report to SGNZ for forwarding to SFF [Achieved]. |
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8 |
31 Dec. 2005 |
Complete assessments of 2005 trials on grower sites and Roselea[2]. Written progress report to SGNZ for forwarding to SFF. |
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9 |
31 Jan. 2006 |
Collate 2005 data. Plan 2006 trials. Grower newsletter with update and plans. Distribute forms/diary for 2006 season record keeping. Identify grower trial sites and confirm protocols and plans for 2006 season. |
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10 |
31 Mar. 2006 |
Written progress report to SGNZ for forwarding to SFF. |
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No. |
Due Date |
Milestone/Deliverable |
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11 |
30 Jun. 2006 |
Establish trials on multiple grower sites. Establish soil condition/water content trial at Roselea site. Check Runner and Elite beds for Phytophthora, report and discuss results with runner growers. Report to growers via newsletter, annual report and workshop and/or Annual Research meeting. Draft ‘Best Practices Protocols’. |
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12 |
30 Sep. 2006 |
Written progress report to SGNZ for forwarding to SFF. |
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13 |
31 Dec. 2006 |
Complete assessments of 2006 trials on grower sites and Roselea. Written progress report to SGNZ for forwarding to SFF. |
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14 |
31 Jan. 2007 |
Collate 2006 data. Plan 2007 trials, if required. Grower newsletter with update and plans. Distribute forms/diary for 2007 season record keeping, if required. Identify grower trial sites and confirm protocols and plans for 2007 season. |
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15 |
31 Mar. 2007 |
Written progress report to SGNZ for forwarding to SFF. |
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16 |
30 Jun. 2007 |
Final report. Presentation at annual meeting. Handbook on soil preparation options (Best Practices Protocols) for both the runner and fruit industries. |
Acknowledgements
This work is funded by Strawberry Growers New Zealand Inc., a MAF Sustainable Farming Fund Grant, Horticulture Australia Ltd, and Elliott Chemicals Ltd. The support of New Zealand strawberry growers, industry representatives and Leicester’s Fumigation Ltd. is also gratefully acknowledged.
[1] Phone discussions with all growers. Met only with those interested in doing trials this year.
[2] Anticipate completion of this milestone approximately early February 2006.
June 2005
This project is designed to develop and implement alternative soil management practices for the strawberry industry following the loss of methyl bromide. It is a three-year programme, boosted by a Horticulture Australia Grant, enabling expansion of the alternative fumigant work and participation by Victoria Department of Primary Industries scientists.
In December 2004, studies of soil physical condition and plant disease were conducted in Auckland and Waikato gardens. There were no obvious differences in soil structural characteristics between healthy and diseased areas, where the vast majority of diseased plants were diagnosed as infected by Phytophthora cactorum.
In an effort to minimise effects of Phytophthora, a trial was conducted in the 2004/05 season to test pre-planting dips and post-planting sprays with phosphorous acid. Strawberry plants were generally healthier, grew better and produced more fruit when they were dipped and/or sprayed with phosphorous acid (0.2% PA solution). A further trial is planted this year to test effects on three different varieties, plus effects in unfumigated ground. Two commercial garden trials were also planted this season.
A large trial was established in the Roselea research garden in Havelock North in early 2005. This trial was primarily aimed at testing alternative fumigant and non-fumigant soil treatments. Pre-plant applications included methyl bromide, chloropicrin, Telone®C35, Fumasol, iodomethane (methyl iodide), mustard oil, urea, compost and an untreated control. These treatments are being tested in both good and in sub-optimal soil conditions. Initial results indicate the fumigants are controlling both pathogens and weeds, but other treatments have had minimal effect.
In February 2005, a survey was sent to all growers to help identify common practices, strengths and weaknesses, plus problems and issues around soil management. These are currently being collected and will be analysed later in the year.
Over the coming year, it is planned to continue the trials outlined above, plus investigate sources of infection in fruit and runner beds to find ways to minimise problems with diseases such as Phytophthora. Testing of runner beds with emphasis on Elite beds form a part of this work.
- Update of the methyl bromide phase-out and an overview of the proposed SFF programme at the Annual Strawberry Industry Research Meeting in Auckland (June ’04)
- Newsletter to all growers, programme detail and invitation to participate (Aug. 04)
- Alternative fumigant trials established on runner grower properties in Katikati (Sept ‘04)
- Trial has established in the Research Garden at Havelock North, to determine the effectiveness of post-infection chemical treatment at eradicating Phytophthora from infested plants.
