Red Palm Mite Project- Interim Report

CABI were approached in February 2008 by Eric Rosenquist to provide assistance in setting up and carrying out foreign exploration for natural enemies of the red palm mite Raoiella indica. The project objectives for CABI were split up into work packages as follow:

Work Package
1) Collection of mites for area of origin study
2) Mite identification/survey technique training in Beltsville for Bryony Taylor
3) Surveys for natural enemies
4) Biological studies of natural enemies

Work Package 1: Collection of mites from the area of origin.

Since the invasion of the red palm mite in the Caribbean, the area of origin of the mite has been a point of interest. This information provides valuable insights into where to explore for natural enemies as part of a classical biological control programme. A limited range of literature is available on the red palm mite however the majority of studies originate from India (31 references on CAB direct), and selected references from Mauritius (1), Egypt (UAR) (2), Oman (1), Iran (1), Sri Lanka (1) and reports in UAE (1), Israel (1), Reunion (1) and Cambodia (1). Raoiella indica has also been synonymised by a number of authors from the following countries Phillipines (1), Pakistan (3). Genetic studies are under way on the mite to determine the relatedness of the invasive mite to the mites in the old world. In preliminary results, the mites in the Caribbean were most genetically similar to those found in India and Reunion, although studies are ongoing currently. Other work by the USDA has included looking into the centre of diversity of the genus, which currently appears to be in Australia.

CABI investigated the host plant list, reviewed literature and visited palm experts at Kew gardens in order to narrow down the possible area of origin of the red

palm mite. Conclusions which have been drawn from the origins of the hosts, point to the diversity of the major host plants being centred in the Malesian area of South-East Asia. The Heliconiaceae are new world hosts and can be discounted from the investigations. With the centre of diversity of the genus Raoiella postulated as being Australia, and the centre of origin of the majority of the Arecaceae and Musaceae hosts hypothesised as Malesia, the centre of origin of Raoiella indica looks to be centred in the Malesian region. Malesia is a floristic province made up of the following countries Malay Peninsula, Sumatra, Java, Bali, and Borneo,Indonesia, the Philippines and New Guinea.

As part of the investigations for locating the area of origin, CABI has formulated a protocol, derived from experienced personnel in the Caribbean and USA to send out to countries within Malesia, with view to surveying for R. indica. Two contacts have been identified and undertaken preliminary surveys in Indonesia and Malaysia and staff from CABI E-UK have undertaken surveys in Papua New Guinea as well as setting up collaborations with institutions within New Guinea to undertake further survey work. As well as organising surveys, CABI has contacted authorities in Malaysia, Indonesia and Papua New Guinea to see if any red palm mites have been detected in routine surveys or during research on palms. Surveys and investigations as yet have not found any red palm mite, however preliminary surveys to look for the mite are continuing.

Work Package 2: Mite identification/survey technique training in Beltsville for Bryony Taylor

Bryony Taylor spent 1 week visiting experts relating to the Red Palm Mite project in Florida and WashingtonDC (Beltsville). Through visiting Amy Rhoda, Jorge Pena, Marjory Hoy, Ron Ochoa and Jenny Beard and a phone call to Cal Welbourn, the following objectives were achieved:

1)Learn to identify breeding population of red palm mite in the field on various host plants.

2)Look at differences in populations of RPM between different host plant available for survey.

3)Learn more about natural enemies associated with RPM in Caribbean and Florida.

4)Learn about current distribution of pest and its updated host list.

5)Learn various culturing techniques for both natural enemies and for the RPM itself.

6)Identify potential experts to aid with identification of natural enemies.

7)Learn to identify the distinguishing feature of RPM down the microscope and how to prepare specimens for such examination.

8)Learn to identify relatives of the RPM in the field which are often mistaken for RPM and also how to identify its common natural enemies.

Work package 3: Surveys for natural enemies.

In order to conduct surveys for natural enemies throughout the season in India, it was necessary to set up a collaborative research programme with a local organisation in an appropriate region. The institute selected was KFRI (Kerala Forest Research Institute). CABI has a long history of successful collaborative research programmes with KFRI and the institute is located in the region of Kerala, known for its coconut and betelnut (Areca catechu) plantations. It is also in the vicinity of Coimbatore where R. indica was first described (Hirst, 1924). As part of the process of setting up a collaborative research programme, a full time research scientist, plus support staff were employed to carry out the surveys throughout the season. Literature from India indicated that the populations of red palm mite peak in April and crash down to very low levels with the onset of the monsoon season and populations are negatively correlated with humidity and rainfall. Population levels remain very low until the end of January when they start to increase in size until the peak in April when temperatures increase. CABI surveys were initiated in late October when populations were still very low in order to assess natural enemies associated with RPM populations when they are both high and low in numbers. Bryony Taylor and Sean Murphy visited KFRI between 20th-31st October 2008 to set up and initiate field surveys for R. indica.

Purpose & Objectives of the visit:

1) Find RPM

2) Set up surveys and select survey locations

3) Train KFRI staff

1) The first objective was to find and locate populations of RPM in the field. Local entomologists were approached at the KeralaAgriculturalUniversity (Professor S. Kurien, Professor AM Ranjith and Professor Jim Thomas) and the Banana Research Institute (Dr Aipa). The visits confirmed that RPM is local to the region, however, they highlighted that large numbers of the mite would not be found in the area until Feb-April during the hot season (in accordance wit the literature). Preliminary surveys were conducted in the districts of Malappuram, Thrissur and Palakkad and local plantation owners were consulted. During these surveys the protocol was refined in accordance with feedback received from both the local entomologists and plantation owners. It was confirmed, when speaking to plantation owners and local scientists that RPM is ubiquitous throughout the region therefore survey sites could be chosen to suit our requirements. They highlighted that they had a problem with RPM on the coconuts and young Areca catechu (betelnut) palms.

2) Two districts were chosen for the natural enemy survey throughout the season. The first survey was set up in the region of Palakkad. This region traditionally has a drier climate compared to that of the climate nearer the coast. The second survey area was set up in the Thrissur district, which has traditionally got a more humid climate compared to Palakkad. As part of the surveys both Cocos nucifera and Areca catechu

were sampled on a monthly basis at each survey site.

Survey sites were set up in 10km strips in each of the regions and palms were chosen at random to be surveyed in this area. Each survey site involved sampling 3 leaflets from a lower frond of a palm no larger than 5m tall. Each leaflet was inspected both onsite and in the lab for the presence of RPM and associated insects and mites. Specimens were stored in alcohol for identification. Each survey visited 20 sites.

For insect identification, it is planned that voucher specimens may be sent to contacts already established. Marjory Hoy has expressed interest in receiving samples of the predatory mite Amblyseius largoensis if found in order to carry out molecular comparisons with those found in Mauritius and the Caribbean. Cal Welbourn has also offered to look at this predatory mite if found and specimens of RPM may be sent to Ron Ochoa for his ongoing population studies. The major problem with insect and mite identification external to India however, is the biodiversity laws bought in by the Indian government. In the state of Kerala there is currently a blanket ban on removing any genetic material from India(live or dead) meaning that the majority of identifications for this project will be carried out in India initially. CABI have set up collaborations with the University of Agricultural Sciences, Bangalore and the Project Directorate of Biological Control, Bangalore to carry out the majority of identifications of the RPM and natural enemies while permissions are sought from central government to export material. Negotiations are currently underway to give permission to CABI for the removal of material for confirmation identifications external to India.

3) Members of KFRI staff were trained in identification of RPM and survey techniques. They were also trained in how to culture the mites and natural enemies.

Work Package 4: Biological studies of natural enemies

Surveys are currently underway in India and one mite in particular appears to be associated with colonies of red palm mite from data sets collated in November and December. Bryony Taylor and Sean Murphy are revisiting KFRI between 9-20th February 2009 and one of the objectives of the trip is to set up preliminary host range studies and to gather initial biological data of this mite in association with the red palm mite colonies. Other objectives of the visit include further investigations into different host plants within India, especially banana and others mentioned on the host list from the Caribbean.