SFF Project Summary
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Updated: 08 September 2009
Latest update
During this project period, the primary project work involved the ongoing assessment of the blackspot infection within the trial block during the late spring and early the summer period.
The results were then collated and the final report completed for the trial period.
The final results from the trial did result in mixed outcomes, although overall the trial did prove to be very successful given that the trial block had no spray treatments for the control of blackspot and the BioVapor only treatment proved successful in significantly reducing the blackspot pressure in the unsprayed trial block.
The results showed that the BioVapor and ground treatment did show a significant reduction in the blackspot level compared with no treatment, although there was no significant difference between the test blocks treated with the BioVapor and ground preparation compared with the blocks treated with the ground preparation only.
There were a number of limitations with the trail block which contributed to the final results achieved, including the fact that the overall size of the block was too small, significant wet areas in the block hampered treatment effectiveness, and that the Granny Smith rows were eliminated from the trial due to a complete lack of any blackspot in this apple variety within the trial block.
The results from this year’s trial has shown that the combination of correct ground preparation and BioVapor ground treatment has the potential to significantly reduce the blackspot pressure on apple blocks in the complete absence of additional spray treatments.
The BioVapor treatment should therefore be considered as a treatment option to be used in conjunction with traditional and organic spray programs to significantly reduce the dependence on spraying for the control of blackspot and associated issues with plant health and reduced crop yields. In certain cases and applications, the BioVapor may have the potential to fully eliminate blackspot sprays and thus providing the grower with the option to market ‘spray-free’ products.
Update
- During this period a detailed project meeting was held involving all project parties to review the results from the 2006 season. Although there were promising results achieved during this season, it was concluded that due to the poor project design and sustained spraying programmes used by the orchard managers, that the results achieved by the BioVapor treatment were not conclusive.
- It was agreed that the overall size of the project should be scaled down and that any further orchard treatments should be conducted on an orchard block where the spray programme is greatly reduced or ideally reduced to zero in order to achieve a conclusive result as to the effectiveness of the BioVapor treatment.
- Subsequent to the project meeting a suitable orchard block has been identified with the orchard manager agreeing to a zero spray program in the block treated with the BioVapor.
- The proposed treatment plan and design was submitted to Pipfruit NZ for approval and on this basis it was agreed that the project continue this season under this new project design. A copy of the treatment plan is attached to this report.
March 2007
During this current project period (1 Nov 06 to 28 Feb 07), the primary activity was the assessment of the treated blocks for black spot disease occurring in the tree canopy. The actual black spot results achieved are looking very promising with most blocks showing very little or no black spot this season despite many blocks having had a heavy black spot problem the previous season. However, due to the limited control plots put in place on some blocks during the initial treatment period, it is difficult to determine the overall effectiveness of the treatment versus the spray program only. A daft report on the results has been completed this period with the final report due to be released during the next project period.
October 2006
North Island Trials:
2006/2007 season
For the 2006 thinning season the focus of these trials has shifted. We have reduced the number of trials being conducted but dramatically increased the level of detail in our data collection at each site to increase our understanding of what is happening in different parts of the tree canopy, on different types of fruiting wood and within individual blossom clusters. Our chemical thinning treatments were based on the treatments showing the most promise in the 2005 thinning season against what we considered ‘industry standard’ treatments and untreated controls.
Prior to any primary thinning sprays being applied initial counting was carried out. All thinning treatments were applied at the appropriate times during the chemical thinning period. Counts to establish the effects of the Primary thinners in all of the trials were completed by late October.
South Island Trials:
2005/2006 trials
Return Bloom Cox One of the observations of some growers using BA as a thinner on cox is that it has had a negative effect on return bloom. Our counts suggest that return bloom seems directly related to the level of thinning achieved in the previous season and not the thinning product used.
2006/2007 season
The objectives for this season are to build on last years’ success of bloom thinning with the combinations of new wetter’s and also try and quantify any other quality differences between the treatments with additional testing. All applications are now complete. Initial post thinning counts have been completed and further fruitlet counts are expected to start late in November.
June 2006
During this final quarter of the project’s first year, all the major milestones were achieved on time as per the project milestone table and the project is now well positioned for a second year of trial work. Again this quarter there was not a lot of project activity due to the seasonality of the project work, however the primary goal of re-designing the BioVapor system to achieve more effective heat transfer onto the leaf litter was successfully completed. The additional leaf litter collected last quarter was also environmentally manipulated during this quarter to try and achieve the accelerated ascospore release. If this is successful, this accelerated release should occur in late July or early August.
The final project team meeting for year 1 was conducted in late June to discuss the first year results and to plan the best approach to the year 2 trials. During this meeting it was concluded if the additional litter samples could not be incubated in sufficient time ahead of the main orchard treatments, or if the litter samples do not get a result after treatment, then the project would progress on a smaller scale of only 5 hectares (1 hectare per orchard block) to minimise the total project costs. If a firm result is achieved with the incubated samples, then the full 25 hectares will be completed. Overall the project team and grower group are very motivated to continue with the project trials for year 2 and to leverage the techniques and lessons learned from year 1.
March 2006
Very little project work was conducted during this past quarter, as expected, due to the seasonality of the project work. As a result of the ground treatment not successfully suppressing the ascospores, no further block assessments were conducted this quarter, with the remaining project funds being reallocated to further litter assessments in the 4th quarter. The only milestone falling into this third quarter was the collection of additional leave litter for assessment in the May/June timeframe.
December 2005
Project Summary
The project started in July 2005 immediately after receiving confirmation from SFF of the successful project application. Given the project contract was not in place prior to the end of the September quarter, this project report covers the period from 1 July to 31 December, 2005.
Over the first six months of the project the first 5 milestones were successfully achieved representing almost 95% of the project costs and time inputs. All of the participating orchards were appropriately prepared and the BioVapor treatment was conducted across a total of 19 hectares. The target was for a total of 20 hectares to be treated, however 1 hectare of Ebro Trellis was unable to be treated due to the narrow row width.
Although the project has been executed within the budgeted time frames and cost estimations, the treatment outcome did not yield a favourable result with respect to the suppression of the ascospore release after the BioVapor treatment. A detailed project report from Greg Tate of Crop Health Services is included in this quarterly report, which outlines the results of the trials to date, as well as the expected reasons for the poor treatment results and the recommended actions to improve the treatment procedure for year 2 of the project.
Although the results achieved in year 1 are very disappointing, the project has achieved a great deal in terms of developing a large scale and sustainable procedure for appropriate orchard litter preparation over the winter to prepare the orchard floor for BioVapor treatment. The procedure for treating large areas of orchard with the BioVapor was perfected during this first year with many design modifications and improvements to treatment procedures and machine design being identified and developed.
In response to the poor results achieved in this first year, a set of modified objectives was developed for the remainder of year 1 and the beginning of year 2 to ensure a better result of ascospore suppression in year 2. The modified objectives can be achieved within the original project budget and will involve design modifications to the BioVapor and efficacy testing of this new design prior to the large-scale orchard treatments in year 2.
The project results and outcomes will be presented to the Pipfruit community at the annual IFP and Organic Pipfruit conferences in Hawke’s Bay and Nelson.
Interim report on Apple BioVapor project: Greg Tate, CHS
Milestones have been met to the present time but a problem with the new BioVapor rig has been identified. Despite its more robust, commercially acceptable design, the current rig failed to completely suppress ascospore discharge from treated litter squares. This result was confirmed when assessing incidence of BS in the BioVapor-treated and untreated apple orchard blocks. Unacceptable BS levels developed in treated blocks.
Fig 1 shows the variable effectiveness across the heat shroud from left to right and from the RHS tree-line nozzle, for inhibiting ascospore discharge from leaf litter squares passed under the shroud. Quite simply it failed to inhibit discharge from this leaf litter. Fig 2 contrasts the result for last years test on an earlier prototype.
Fig 3 shows the results of the second litter squares test comparing the efficacy of Biosea alternatives. Because the BioVapor + Biosea treatment this season was not 100% effective, the results for the oils test were invalidated and no conclusions can be drawn. These litter squares were passed under the shroud at between positions 4 and 5 which did not completely inhibit ascospore discharge.
Fig 4 shows the incidence of leaf BS by 17 November in treated and untreated blocks. Ten trees in the centre of each block were searched up to head height for the total number of leaves with BS. These levels are equivalent to >1-2 diseased leaves per tree, an unacceptable level of BS following spring BioVapor + BioSea treatment.
This confirms the initial conclusion from Fig 1 that the new rig did not perform well. The blocks where no BS was recorded simply reflects good spraying performance by the managers, as evidenced by the BS levels in Andrew Peacock’s block where several BioVapor+ BioSea-treated rows were left unsprayed.
The heat shroud and heat delivery design was re-examined and concluded to be superior to last years prototype. The temperature profile beneath the shroud was good, with static temperatures of 140-160 C being achieved, cf 120-140 C for the previous model. Side delivery temperatures were also high, with a much higher air flow for tree-line treatment than in the last prototype.
Factors like ground preparation, forward travel speed, water injection and Biosea delivery were then examined.
Ground preparation was considered to be very good this year and not a limiting factor.
Forward speed at 3.5 km/hr, while 0.8 km/hr faster than last year shouldn’t have mattered with the higher heat output achieved.
Water injection was found to be significantly lower than for the previous prototype which had operated on a (relatively short-life) spirojet steam generator, while the new rig had long-lasting injectors. The problem was that too few had been installed to provide sufficient water for the larger capacity burner. Thus a drier heat was produced without the capacity for rapid heat exchange as in the former prototype. This is important due to the short time (about 2 seconds) that leaf litter is exposed to the BioVapor treatment.
While the two floodjet Biosea nozzles plus a filtering system in the Biosea tanks were considered to be an improvement on the previous model, it was considered that further improvement was still required to achieve an even spray swathe pattern. It was possible that the litter was not evenly coated with Biosea after the rig had passed over. Additionally a fail-safe system for instantly detecting nozzle blockages is required to prevent treatment failure.
This result in the first season of the project is regrettable and an improved system cannot be retested in this season on apple litter. Further developmental work is obviously required to recapture the efficiency of the previous BioVapor rig and improve the Biosea delivery and monitoring systems while retaining the robustness and finish of the current rig.
A similar rig tested on grape leaf litter this spring for botrytis suppression also failed, even after doubling the water injection rate by installing more injectors, and reducing burner heat output to increase vapour content of the hot air flow. In previous tests it was found that best results occurred with the BioSea temperature at 100 C (at which water vapour content was highest) than at 200, or 300 or 400 C, which appeared to reduce vapour levels in the hot air stream. The current rig has much greater heat output capacity.
There is still time to restore rig efficiency before next season’s trials start. Apple leaf litter will be collected next autumn and refrigerated to shorten the winter chill requirement so that further shroud efficacy tests can be completed prior to August-Sept when the trial blocks will need to be retreated. Any further shroud adjustments can therefore be made if required.
The alternative oils treatment will also need to be repeated to provide cheaper alternatives than Biosea for IFP growers.
