Integrated pest management in a sustainable production system for Brassica crops in Fiji and Samoa

Objective 1: To demonstrate effective integrated approaches to Brassica pest management
Due to the unavoidable delay to the start of project activities, the workshops and farmer extension sessions were postponed; they will now be held in early September, 2006. Despite the delay, several stakeholder and technical meetings were held in November 2005; these established an introduction to the project and preliminary planning sessions were conducted (additional technical meetings were held in June 2006 ; Objective 3).

Seminars and discussion groups were held to introduce stakeholders to the project's approach and goals at:
SPC, Suva (Fiji). The meeting was attended by approximately 20 stakeholders including farmers, SPC and MASLR extension officers and officers from the Fiji Ministry of Health. In an additional meeting, technical aspects of the project were discussed by MASLR, SPC, University of Queensland and QDPI&F project team members.

Nu'u crop research station (Samoa). The meeting was attended by approximately 15 stakeholders including farmers, MAF, SPC, University of Queensland and QDPI&F technical and extension staff. In a supplementary technical meeting, project team members (MAF, SPC, UQ and QDPI&F) discussed issues related to the project for the coming 2006 season.

The participatory trials to demonstrate the essential elements of effective Brassica IPM trials have not yet been set up but they will be conducted to coincide with the planned workshops in early September in both Fiji and Samoa.

Objective 2: The introduction of a FFS approach for improved sustainable production systems in Brassica crops and effective communication of project outputs
A possible master trainer for the training of local extension officer personnel in FFS techniques has been identified, training session are expected to begin in the current crop season. Appropriate community/ farmer groups have been identified for the basis of FFS in Fiji and Samoa. It is anticipated that training will have begun and be ongoing by the time of the September workshops; the first field testing of the toolkit will be undertaken around the workshops. Team members in Fiji and Samoa regularly liaise with DSAP team members. A key member of the IPPSI project team is now a PhD student at the University of Queensland, this close link between personnel between both projects will ensure effective bilateral information exchange and cooperation.

Objective 3: To determine the role of major natural enemies in the management of Brassica crop pests
Regional surveys (on farms and research stations) to determine the key insect pests of Brassica crops and their associated natural enemies began in June 2006 in both Fiji and Samoa. Continuous data collection for the next two years (June 2006- May 2008) will build up this inventory. Local scientists have received training relating to survey techniques and insect identification.

Preparations for experiments to determine the impact of relevant natural enemies on populations of diamondback moth are underway in both countries. The experiments will be performed later this season and will provide valuable preliminary information regarding the structure and function of the endemic natural enemy complexes in the Brassica agro-ecosystems of both countries.

Preliminary data indicate that some important natural enemies of the diamondback moth are present in both countries. Arrangements have been made to receive a population of a heat tolerant biotype of Diadegma insulare from Florida into the quarantine facility at the University of Queensland. Experiments have investigated the relative foraging efficiencies and survival of adult and immature D. semiclausum at a range of temperatures. Preliminary results indicate that D. semiclausum forages effectively at temperatures up to 25C, however at temperatures of 25C and above successful development to adult stages is severely disrupted. Suitable protocols for comparing the performance and survival of D. semiclausum and D. insulare at a range of temperatures in the laboratory have been devised.

Objective 4: To develop a refined local IPM strategy using selective plant protection products
Selective plant protection products have been sourced and transported to Fiji and Samoa for testing. Products will initially be tested in the laboratory and then field tests will be conducted accordingly. In Australia, laboratory tests on the relative efficacy of a Neem formulation against P. xylostella and C. pavonana are currently underway. These preliminary experiments will be completed by the time of the workshops in September and results will be discussed with team members.

Current action thresholds for intervention are based on the assessment "standard" insect measurements. These relative values are based on the total foliage consumption by first to final stage larvae of each species. Preliminary experiments measured the relative foliage consumption of P. xylostella and C. pavonana in the laboratory. Individual C. pavonana larvae consumed approximately 13-times more cabbage foliage than individual P. xylostella larvae. Based on the standard insect assessment, one C. pavonana larva represents 2.6 standard insects.

Objective 1: To demonstrate effective integrated approaches to Brassica pest management
The postponed workshops and farmer extension sessions were conducted in September 2006. They were attended by more than 30 participants in Samoa and more than 150 participants in Fiji. Participatory trials to demonstrate the essential elements of effective Brassica IPM were set up in both countries in June 2007 and followed on from the FFS workshops (see Objective 2 below). Further participatory trials are underway and will be completed in September/ October 2007.

Objective 2: The introduction of a FFS approach for improved sustainable production systems in Brassica crops and effective communication of project outputs
A FFS master trainer from the FAO IPM programme in the Philippines ran two-week long training activities in Samoa (May 21-31, 2007) and Fiji (June 4- 15, 2007) to acquaint local extension officers with FFS techniques. In Samoa 24 participants took part in the training and in Fiji 22 participants were involved. During the training activities the participants formed groups to conduct a pilot FFS on a research station in each country following the intensive two-week long training activities. To ensure that the pilot FFS activities were adequately supported in their early stages, the master trainer visited each FFS group approximately two weeks after the completion of the training.

Objective 3: To determine the role of major natural enemies in the management of Brassica crop pests
Regional surveys to determine the key insect pests of Brassica crops and their associated natural enemies began in June/ July 2006 in both Fiji and Samoa. Data on pest abundance was collected weekly at experimental sites in both countries. In Samoa diamondback moth (DBM) abundance was high in July and September 2006 but declined to low levels by mid February 2007 and the pest was not detected in the field after April 2007. Large cabbage moth (LCM) populations were high in August and September 2006 but declined through December, January and February before reaching high levels again in April through July 2007. Pest surveys in Fiji have been more extensive (conducted weekly at three research stations) and have recorded more pests than the surveys in Samoa. In Fiji in addition to DBM and LCM, Spodoptera littura, Trichoplusia ni, Helicoverpa armigera and aphids have been recorded on Brassica crops. At Koronivia research station DBM populations were high from July through December 2006 but remained very low through to the end of June 2007. At Legalega research station the DBM population reached a maximum in October 2006 but the pest was only recorded infrequently at this site from November 2006 to June 2007. At Sigatoka research station DBM populations reached a maximum in December 2006 and the pest was only recorded at very low densities at the site between December 2006 and June 2007. LCM was recorded at Koronivia and Leglega research stations throughout the surveys but it was not recorded at Sigatoka after February 2007.

Collections of DBM in Fiji have confirmed that the larval parasitoid Cotesia vestalis (=plutellae) Haliday and the larval pupal parasitoid Oomyzus sokolowskii Kurdjumov are established at all three sites. Collections of DBM in Samoa have confirmed the presence of C. vestalis and O. sokolowskii in the country. Both C. vestalis and O. sokolowskii are effective at higher temperatures than D. semiclausum and have the potential to be useful biological control agents in both countries; their impact on DBM populations will be measured. The recovery of these parasitoids from DBM in both Fiji and Samoa indicates that releases of exotic parasitoids are unlikely to be necessary in either country.
Only limited collections of LCM have been undertaken in Fiji and no egg or larval parasitoids have been recovered. Limited collection and rearing of LCM larvae has failed to detect any larval parasitoids of this pest in Samoa but Trichogramma chilonis has been discovered parasitising egg masses of LCM.

Natural enemy exclusion experiments in Fiji have revealed the importance of predators (and possibly abiotic factors) as causes of mortality in experimental populations of DBM.

Objective 4: To develop a refined local IPM strategy using selective plant protection products
During the FFS training courses, preliminary IPM management programmes were devised for Fiji and Samoa. These programmes, which are based on the threshold directed application of Bt in response to the combined pest complex, were tested by members of the FFS and compared with control and current farmer practice. The experiments will be completed by late August and reported on in the next annual report.

Objective 1: To demonstrate effective integrated approaches to Brassica pest management
A trial conducted at Sigatoka research station tested a preliminary IPM strategy against current farmer practice and control (no intervention) treatments. The experiment showed that IPM effectively managed the pest complex (diamondback moth (DBM) and large cabbage moth (LCM)), promoted natural enemy activity and resulted in crop yields which were = yields achieved by farmer practice. A similar experiment was conducted at Nu'u crop research station in Samoa March- May 2008 but the data is yet to be received. A refined version of the preliminary IPM strategy will be tested in both Fiji and Samoa in the 2008 growing season.

Objective 2: The introduction of a FFS approach for improved sustainable production systems in Brassica crops and effective communication of project outputs
Following the FFS train the trainer activities (Samoa: May 21-31, 2007; Fiji: June 4- 15, 2007) reported on previously the master trainer revisited each FFS group shortly after its inception to help deal with any problems and provide addition support during the early stages of activities. The FFS groups in both countries were not sustained following the departure of the master trainer. The FFS train the trainer activities for 2008 have been postponed until July and August as inclement weather in Fiji has delayed the preparation of field training plots. The sustainability of FFS activities following the departure of overseas project team members will be specifically addressed in the forthcoming training activities. Project outputs were communicated by oral and poster presentations at the
Australia and New Zealand Biocontrol Conference, Sydney 10-14 February 2008. In 2007 a documentary explaining the aims and objectives of the project was broadcast on national television networks throughout the Pacific Island countries and territories. In December 2007 the project leader traveled to Solomon Islands and worked closely with entomologists involved in ACIAR project HORT/2003/047 to develop approaches to survey Brassica crops for pest insects and their natural enemies.

Objective 3: To determine the role of major natural enemies in the management of Brassica crop pests
Regional surveys have confirmed that the DBM parasitoids Cotesia vestalis and Oomyzus sokolowskii are widely established in the major Brassica crop growing areas of Viti Levu, Fiji. The surveys did not record any parasitoids of LCM. In September 2007 a large study to measure the impact of natural enemies on experimental populations of DBM was conducted at Sigatoka research station. The work showed that both C. vestalis and O. sokolowskii can be effective parasitoids of DBM in Fiji and that considerable pest mortality also occurs in cabbage crops due to the combined action of generalist predators (predominantly spiders and ants). In Samoa the establishment of C. vestalis and O. sokolowskii has been confirmed but no studies have yet measured their impact on pest populations (extremely low field populations of the pest have been recorded following its seasonal decline in the 2007 wet season). Regional surveys have recorded LCM egg masses attacked by Trichogramma chilonis at a number of sites on Upolo and preliminary studies to assess the impact of the egg parasitoid on its host indicate that it may have a significant role to play in an IPM programme.

Objective 4: To develop a refined local IPM strategy using selective plant protection products
Preliminary IPM programmes based initially on threshold directed intervention with foliar applications of Bacillus thuringiensis have been developed and tested. Initial studies indicate that DBM thresholds are appropriate but that LCM thresholds will need some revision, revised thresholds and a modified sampling plans will be tested in the 2008 field season. The efficacy of a range insecticides (Prevathon (rynaxphur), Steward (indoxacarb), Match (lufenuron), Delfin (Bacillus thuringiensis - kurstaki) and Xentari (Bacillus thuringiensis- aizawi) was tested against the insect pest complex of Brassica crops in a field experiment conducted at Sigatoka research station in the latter half of 2008. The performance of these compounds was compared to that of a synthetic pyrethroid (prophylactic application of which is currently standard practice for most farmers in both Fiji and Samoa). The selective insecticides performed better than the synthetic pyrethroid and the study indicated that both formulations of Bacillus thuringiensis are suitable for inclusion in IPM strategies against the Brassica pest complex in Fiji.