SFF Project Summary
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| Updated: | 03 October 2008 |
| Related links: | www.aphidwatch.com www.thegrower.co.nz www.crop.cri.nz www.hortnz.co.nz |
| Final report [ 87K PDF] | |
| Latest Update |
Project description
The key output from this project is the transfer of new technology in pest and disease management to outdoor lettuce growers and crop scouts. This project is the two-year implementation phase of the Integrated Pest and Disease Management (IPM) for Outdoor Lettuce project (SFF Grant 02/027).
The issue/opportunity
Following on from the development phase project, the current project is aimed at filling the most significant remaining knowledge gaps and making available to all NZ lettuce growers a comprehensive IPM programme for outdoor head lettuce production. This will assist in improving crop production practices in such areas as slowing the development of resistance and overuse of pesticides.
Many of the effective management strategies developed in the previous project have only been tested for the Pukekohe region and these need to be validated in the other main lettuce growing regions.
The context/background
The 3-year SFF project covering the development phase of an IPM programme for outdoor lettuce finished in June 2005. There was almost no relevant research on lettuce in NZ completed prior to that project. In a relatively short time, the project produced a number of new pest and disease management strategies including effective management of the new major pest currant lettuce aphid (Nasonovia ribisnigri).
The new knowledge needs to be disseminated throughout the industry because previously it has largely been available only to the few key growers involved in the development phase. Previous experience in NZ and overseas has shown that training of growers and crop scouts in the field is an important component in the successful implementation of IPM programmes.
The project team includes growers from three important lettuce growing regions (Pukekohe, Gisborne and Horowhenua) and other key industry partners. Crop & Food Research is the primary science provider to the project.
Methods
Regional validation trials will be used as demonstration and training sites for growers and crop scouts in other regions. The information guide for outdoor lettuce, completed at the end of the IPM development phase project (June 2005), will be developed further and produced as an IPM manual (incorporating information from regional validation trials and grower feedback).
Some further research will be conducted to fill identified gaps in knowledge required to deliver a comprehensive IPM programme. This research will involve validation of action thresholds for key pests, investigation of spray application technologies and timing for foliar and soil-borne diseases of lettuce.
Latest Update: March 2007
Refinement and validation of IPM strategies
Late spring/summer insect field trials were completed in Horowhenua and Christchurch. These trials were to assess if natural enemies (in particular insect predators) can control lettuce aphid in these regions during these seasons without the use of imidacloprid drenching of transplants (standard practice). Two of the three trials in Horowhenua resulted in pest-free crops, but the 3rd trial and the trial in Christchurch had unacceptable aphid infestations at harvest. This failure to control lettuce aphid may have been due to the unusually cool spring, which may have delayed and reduced the build-up of natural enemies in these regions. It is noteworthy that 4 years of data from the Pukekohe region confirm that natural enemies control lettuce aphid in spring and early summer without the need for drenching transplants with imidacloprid. This technique (biological control) is recommended for the Pukekohe region in spring and early summer as a 'window period' when imidacloprid is not used. This is considered an important strategy that will enable the region to minimise the risk that resistance will develop in lettuce aphid populations to this chemical.
Suction traps at Lincoln, Hastings and Pukekohe are being maintained and numbers of lettuce aphids captured are posted on www.aphidwatch.com. The most obvious highlights of the aphid flight levels this summer have been that Pukekohe numbers have been very low when compared to the previous three years, Lincoln numbers were extraordinarily high - much higher than we have ever seen before, and Hastings remains on par for an average year.
The summer caterpillar threshold and thrips control trial is underway at Pukekohe Research Centre. The trial was planted on 13 February and is being sampled weekly. Harvest assessment will be in mid April. This study will provide good data on the impact of selective foliar insecticides for caterpillar pests and their impacts on natural enemies.
All lettuce disease research has been completed on target. Disease research included field experiments to (1) evaluate fungicides for the control of downy mildew of lettuce, (2) determine the effects of spray technologies and adjuvants on downy mildew of lettuce, and (3) investigate control methods for Sclerotinia leaf drop of lettuce. All disease research is currently being written-up and will be reported in scientific papers, conference proceedings, grower workshops/seminars and grower magazines.
Documentation
The IPM manual is being reviewed and all sections are now in a near-final state except section 12 (Crop monitoring and management decisions). Completion of the final version of this section is dependent on obtaining results from insect trials still underway at Pukekohe.
Dissemination and evaluation
A regional seminar and grower field day was held at Pukekohe Research Centre on 19 February attended by >50 people. Only a small number of scout trainees have been nominated this year with the majority based in Gisborne. Therefore, because the key scouts from Horowhenua were trained last year, it is proposed that scout training workshops be held in Gisborne rather than Horowhenua. A grower survey is planned for May.
Publications
A manuscript 'Indirect non-target effects of aphicides on the Tasmanian brown lacewing (Micromus tasmaniae) through aphid feeding on lettuce aphid (Nasonovia ribisnigri)' has been submitted to 'Biological Control'. A number of other publications are being prepared, mainly for publication in 'New Zealand Plant Protection' and 'Grower'.
Quarterly Update: October 2006
Refinement and validation of IPM strategies
Three spring/early summer trials have been organised for November planting. These will repeat studies conducted last year to determine if lettuce crops can be grown and managed successfully without the use of Confidor drenches. A spring trial set up at a new site in Marshlands (Canterbury) was harvested was harvested on 07 November.
Suction traps at Lincoln, Hastings and Pukekohe are being maintained and numbers of lettuce aphids captured are posted on www.aphidwatch.com .
Data from monitoring of soybean looper using male and female lures have been analysed and presented in a paper “Monitoring of Thysanoplusia orichalcea in New Zealand” at the 5th International Workshop on the Management of Diamondback Moth and Other Crucifer Pests in Beijing, China in October.
The replicated trial at Gisborne including cultivars regarded by seed suppliers to be tolerant to lettuce big vein disease was harvested in August. Very high levels of infection of LBVD were observed across all cultivars. The current standards Wintergreen and Winguard produced the highest percentage of marketable heads.
An experiment to evaluate 10 fungicides for efficacy against downy mildew has been completed at Pukekohe. Fungicides tested were Amistar WG, Kocide 2000, Acrobat MZ 690, Sereno, Aliette WG, Foli-R-Phos, Manzate, Melody Duo, Ridomil and Antracol. A paper presenting the results is in preparation.
Another experiment at PRC investigated the effects of spray application technologies (water rates, nozzle types and angles) and adjuvants (an non-ionic surfactant, an organosilicon and a pinoline compound) for control of foliar pests and diseases of lettuce. This experiment was harvested on 25 October and results (spray deposition, downy mildew infection) have yet to be analysed.
A third experiment investigated the effects of 4 fungicides (procymidone, carbendazim, Filan, and Pristine), hydrated lime and Trichoderma on sclerotinia leaf drop caused by Sclerotinia minor. The field site was artificially inoculated with sclerotia of the pathogen prior to transplanting. This experiment was assessed on 19 October and a repeat planting was made on 06 November .
Documentation
Grower members of the project team met on 05 November 2006 to discuss formats for publication of the IPM manual. Proposals for a ‘ute guide’ and a full manual in CD-ROM form are being developed.
Dissemination and evaluation
The third scout training workshop was held at Pukekohe Research Centre on 04 October 2006 and was attended by 18 crop scouts. The focus of this workshop was on identifying and controlling plant diseases. Expressions of interest in a second round of training workshops in 2007 are being sought from growers.
Publications
Two oral presentations were made at the NZ/Australia Entomological Society Joint Conference in Adelaide, 20-22 September, 2006: “Indirect non-target effect of aphicides on Tasmanian brown lacewing (Micromus tasmaniae) – impacts on IPM” and “IPM for insect pests in outdoor lettuce in New Zealand”.
June 2006
Refinement and validation of IPM strategies
A replicated trial including cultivars regarded by seed suppliers to be tolerant to lettuce big vein disease has been established in a LeaderBrand Produce crop near Gisborne. This trial will be harvested in August.
Seedlings for several field experiments to be planted in July have been produced in cells at Pukekohe Research Centre.
One winter/spring experiment will valuate 9 fungicides for efficacy against downy mildew. Fungicides to be tested are Amistar WG, Kocide 2000, Acrobat MZ 690, Sereno, Aliette WG, Foli-R-Phos, Manzate, Melody Duo and Antracol.
Another experiment at PRC will investigate the effects of spray application technologies (water rates, nozzle types and angles) and adjuvants (an non-ionic surfactant, an organosilicon and a pinoline compound) for control of foliar pests and diseases of lettuce.
A third experiment will investigate the effects of 4 fungicides (procymidone, carbendazim, Filan, and Pristine), hydrated lime and Trichoderma on scerotinia leaf drop caused by Sclerotinia minor. The field site will be artificially inoculated with sclerotia of the pathogen prior to transplanting.
Suction traps at Pukekohe, Hastings and Lincoln are being maintained weekly. Results are posted on www.aphidwatch.com . At Pukekohe and Hastings the peak in lettuce aphid activity occurred at the same time as last year. At Hastings, LA numbers were higher than at the same time last year but lower than in the previous two years. At Lincoln, the peak in LA numbers in mid-April/early May was almost a month later than normal. Discussions are underway as to whether to continue funding the North Island suction traps throughout the next year.
Documentation
There has been little progress made on the IPM manual in this quarter.
Dissemination and evaluation
The third scout training workshop has been rescheduled from May to early October 2006. The revised timing should ensure more symptoms of plant diseases in the trials at PRC. Following the first two workshops at Pukekohe, a Canterbury grower has requested that his crops be part of the technology transfer programme.
Publications
Anon., (2006). Saving our salad. Estimating the economic contribution of biotechnology to New Zealand’s primary sector. NZ Ministry of Research, Science & Technology.
A number of other papers are in preparation, including several abstracts for oral presentations at the NZ/Australia Entomological Society Joint Conference in Adelaide, 20-22 September, 2006. A paper on indirect effects of imidacloprid, pirimicarb and pymetrozine on Tasmanian brown lacewing feeding on intoxicated LA has been submitted for publication.
March 2006
Refinement and validation of IPM strategies
Insecticide trials completed in this quarter evaluated control action thresholds for soybean looper larvae (Pukekohe) and control of currant lettuce aphid by natural enemies in the absence of insecticide (Horowhenua and Canterbury).
For both insecticides, use of an action threshold of 0.5 larvae per plant kept medium and large soybean looper larvae below one per plant. Pest damage assessments undertaken at crop maturity have yet to be analysed.
Predators did not control lettuce aphid to an acceptable level in the Pukekohe summer trial. In Horowhenua, lacewings appeared to be the key predator in producing lettuce crops free of aphids at harvest with hoverflies, 11-spot ladybird beetles and spiders also active. Predators also appeared to control aphids in two trials in Canterbury (data analysis not yet complete).
Monitoring of adult flights (male and female pheromone trapping) of soybean looper (Thysanoplusia orichalcea) has continued at 5 sites. A planned autumn caterpillar action threshold trial at PRC has been cancelled due to financial constraints in the project.
Suction traps at Pukekohe, Hawke’s Bay and Christchurch are being maintained weekly. Results are posted on www.aphidwatch.com.
Documentation
The second edition of the information guide was published in January 2006 and has been supplied to all crop scout trainees as the main resource for training.
Dissemination and evaluation
The first two of three crop scout training workshops were held at PRC on 08-Feb and 08-Mar, attended by 20 and 19 trainees respectively. The third workshop has been rescheduled from May to early October 2006. The revised timing should ensure more symptoms of plant diseases in the trials at PRC.
Scout training in commercial crops has continued in Horowhenua.
Graham Walker and Peter Wright gave oral presentations on project progress at CFR Lincoln (28 Feb, Horticulture NZ Leafy Crops Product Group) and Vegetable Technical Conference (Pukekohe, 16 Mar).
December 2005
Refinement and validation of IPM strategies
Lettuce trials without insecticides are underway or completed at Pukekohe, Horowhenua and Canterbury. It is anticipated that these will demonstrate that insecticidal treatment against the currant lettuce aphid is not required in spring-early summer lettuce crops in these regions, where aphid:predator ratios are typically below the provisional action threshold of 10:1.
Suction traps at Pukekohe, Hawke’s Bay and Chrischurch are being maintained weekly. Results are posted on www.aphidwatch.com .
Monitoring of adult flights (male pheromone trapping) and crop infestations of soybean looper (Thysanoplusia orichalcea) larvae have continued at 5 sites. A female floral attractant was applied to traps at these same sites. Catches of female moths were much lower than male moths (1:100 to 1:10) but followed a similar seasonal pattern. Female trapping may be a more efficient monitoring tool as male trap monitoring is time-consuming due to the large number of males trapped.
Field trials to evaluate fungicide treatments for efficacy against downy mildew and sclerotinia leaf drop (SLD) were planted at PRC in Sep-05. Downy mildew did not occur at the experimental site and the experiment will be repeated in autumn-winter 2006 when cooler, wetter conditions should be more conducive to infection and disease development. Untreated lettuce had an incidence of SLD of 64% (dead plants at crop maturity). A range of fungicides gave better control of SLD (9-26% of plants affected) than hydrated lime (37-41%) and/or Trichoderma (37-41%).
A trial to test the efficacy of various spray application technologies (water volumes, nozzle types and angles, adjuvants) against foliar disease was unsuccessful due to the lack of downy mildew infection at the site and will be repeated in autumn-winter 2006.
Documentation
The second edition of the information guide was completed in December 2005 and will be published in January 2006.
Dissemination and evaluation
Crop scout training has begun in Pukekohe and Horowhenua in regional trial sites and commercial crops. Preparations are underway for three training workshops for crop scouts at Pukekohe on 08-Feb, 08-Mar and May 2006. There are 20 registrants for these workshops including growers and crop advisors from Pukekohe, Gisborne, Horowhenua and Canterbury.
General
ConfidorR as a transplant drench was registered on 20-Dec-05 for lettuce transplants, with much of the supporting data generated by the development phase of this project.
Publications
Walker, G P; Martin N A; Griffin, B; Falloon, R; Teulon, D. 2005. Research on pesticide risk reduction. Poster at: Integrating initiatives for Pesticides Risk Reduction Workshop, Environmental Risk Management Authority, Wellington, 1 December 2005.
September 2005
Refinement and validation of IPM strategies
An untreated susceptible cultivar of lettuce was planted at Pukekohe Research Centre (PRC) on 14-Sep-05. It is anticipated that this will demonstrate that insecticidal treatment against the currant lettuce aphid is not required in spring-planted crops at Pukekohe. Spring crop trials are being planned for Canterbury, Horowhenua and Gisborne.
Suction traps at Pukekohe, Hawke’s Bay and Chrischurch are being maintained weekly. Results are posted on www.aphidwatch.com .
Monitoring of adult flights (male pheromone trapping) and crop infestations of soybean looper (Thysanoplusia orichalcea) larvae began in September at Pukekohe. Surveys are being conducted for bogong moth (Agrotis infusa), a new incursion into NZ, discovered on a lettuce trial at PRC last February. MAF are considering instigating an eradication programme if the pest has overwintered.
Field trials to evaluate fungicide treatments for efficacy against downy mildew and sclerotinia leaf drop were planted at PRC on 14 September.
Documentation
The limited edition draft information guide was completed and distributed for comment and feedback. It consists of over 120 pages including 80 colour illustrations and additional resource materials. The guide includes crop scouting reporting sheets and preliminary control strategies for pests and diseases of lettuce in the Pukekohe region. The revised document will be used as the primary resource for grower/scout training and will be developed into an IPM Manual during the course of the project.
Dissemination and evaluation
Specimens of the important insect pests and their natural enemies have been collected and stored for use in the scout training workshops planned for the first half of 2006.
Publications
Fletcher, J D; Butler, R C; France, C M (2005). Lettuce viruses and management of big-vein disease in New Zealand. 15th Biennial Australasian Plant Pathology Society Conference, Geelong, Victoria, 26-29 September, 2005.
Wright, P J (2005). Control of Sclerotinia leaf drop of lettuce. 15th Biennial Australasian Plant Pathology Society Conference, Geelong, Victoria, 26-29 September, 2005.
