June 2010. Cook Islands asked a question about the biological control of two thrip species using the general predator, Montandoniola moraguesi. The situation in the Cook Islands was described as thus:

???The Cuban laurel thrips Gynaicothrips ficorum and the red-banded thrips Selenothrips rubrocinctus have become major pests on Rarotonga since their discovery in November 2009. Swarming G. ficorum are a nuisance for people, and S rubrocinctus causes severe damage on avocados. Natural enemies are not able to control these thrips species. We are, therefore, considering a biological control programme with the introduction of Montandoniola moraguesi. This anthocorid is recorded to be a general predator of thrips and has been used successfully in the past to control Cuban laurel thrips in Bermuda and Hawaii.???

Two questions were posed:

1. Are there any records or observations of M moraguesi preying on red-banded thrips; and
2. Where could a population of M moraguesi be obtained?

There was concern about using a general predator for the control of this pest, and the following questions were asked:

• Do you know what native thrips are present in Cook Islands?

• Will an assessment of the impact of M moraguesi on the two thrips be made before deciding to introduce a general predator?

• Perhaps some PestNet members know of a more specific parasite or predator for either of the two thrips mentioned.

Another member looked at the problem of M. moraguesi introduction in a different way. What if thrips were needed at a later date for weed control? He took the example of control of the weed, Mikania micrantha.

In Trinidad, M. moraguesi is a predator of Liothrips mikaniae ??? the potential biolcontrol agent of Mikania micrantha. L. mikaniae is not the only thrips biological control agent for weeds. Liothrips urichi provides control of Clidemia hirta in Fiji, and partial control in Hawai???i. Another Liothrips species is being studied in Florida for biological control of Schinus terebrinthifolius was tried in Solomon Islands and Malaysia. It is not known why it failed in Solomon Islands, but in Malaysia failure was due to indigenous predators, especially a predatory thrips. It was hoped that L. mikaniae might prove more effective in some of the Pacific Islands with less diverse/effective thrips natural enemies. (However, in the meantime what appears to be a very promising rust fungus is being tried against M. micrantha in India and China.

L. mikaniae is not the only thrips biological control agent for weeds. L urichi provides control of Clidemia hirta in Fiji, and partial control in Hawai???i. Another Liothrips species is being studied in Florida for biological control of Schinus terebrinthifolius.

Therefore, countries contemplating the introduction of a thrips predator should not only consider the impact on indigenous thrips, but also the possible implications for the use of thrips as weed biological control agents.

Returning now to Selenothrips rubricinctus, this is also a pest in Trinidad, in spite of the presence of M. moraguesi, so the anthocorid may not be an effective predator of S rubricinctus.

There is a parasitic eulophid, Goetheana shakespearei (= parvipennis) which is an almost cosmopolitan species that attacks S. rubricinctus and other thrips and is credited with a giving a degree of control of S. rubricinctus in some areas. It was introduced in Trinidad in the 1930s, but although established, widespread and attacking S. rubricinctus, it does not exert substantial control. The host range of G. shakespearei is restricted to Thripinae and Panchaetothripinae, and it does not seem to include Phlaeothripinae, so although it is almost certainly more specific than M. morgauesi, there would still be a need to consider the implications for indigenous thrips. Phlaeothripinae includes Liothrips, and G. shakespearei did not attack L. mikaniae in Trinidad, so the implications for weed biological control are clearer. This parasitoid might be considered, if it is not present in the Cook Islands already. However, a comprehensive literature survey may also turn up other possibilities.

Another member, said that he had introduced the anthocorid Montandoniola moraquesi (Puton) from Hawaii in September 2001 for biological control of the Cuban laurel thrips, Gynaikothrips ficorum (Marchal) on several Ficus spp. in Thailand. After field releases the anthocorid has become established, widely spread and given a substantial control of G. ficorum. The anthocorid is originally native to and introduced from the Philippines to Hawaii in the 1960s.

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