Pests > Pest Management > Biological control > Bioagents – insects > Brontispa, coconuts > Parasitoids/predators Brontispa, Philippines

Brontispa longissima, Philippines

April 2009. A number of provinces of Philippines have infestations of Brontispa longissima, and quarantines have been declared to prevent further spread, including banning imports of coconuts palm seeds and seedlings from a number of countries. In addition, the Department of Agriculture and the Philippine Coconut Authority (PCA) have advocated trunk injections, spraying and the use of earwigs.

A member asked why the Philippines has chosen pesticides and earwigs to manage Brontispa when other countries have introduced parasiotids of one kind or another, in some cases, more than 40 years ago, and with great success.

Offers of parasitoids were received from many members, and others spoke of their success with Asecodes hispinarium (except Vietnam); however, the Philippines authorities have been trying to import this parasitoid, but their biosecurity is very stringent; this is why the Bureau of Plant Industry has resorted to earwigs, and Metarhizium, while PCA has recommended pesticides.

One member held a slightly contrary view. While it is true that earwigs are general predators and likely to consume both healthy and parasitized insects, they may still have potential. A study carried out in Samoa in the mid-1980s suggested that Chelisoches morio was the most important biological control agent for Brontispa longissima in the infested coconut leaf samples collected at several sites around the island of Upolu. This work was published in the Alafua Agricultural Bulletin. Trying to assess the pest regulation effects of a predator under natural conditions is more difficult than assessing the importance of a parasitoid, for which percent parasitism can be measured easily. The importance of these predators was based on the fact that they were very common in samples, and they readily consumed the pest when confined in containers with infested coconut leaflets.

For research on chemical control in Singapore, see: www.ava.gov.sg/NR/rdonlyres/5A163534-CCA6-4956-8D79-97688A0FF681/20655/AV Achapter8.pdf.

Later, July 2010.

T. brontispae is a well-known parasitoid of B. longissima, but it is nowhere near as efficient and effective in controlling Brontispa as Asecodes hispinarum, which was introduced with FAO assistance in 2003/2005 in VietNam, Cambodia, Lao PDR, PR China, Thailand and Maldives for control of B. longissima. In-depth studies and monitoring in southern Vietnam and Maldives showed that pest populations decreased dramatically (over 99%) within 1-1.5 years after the initial introduction of the parasitoid, which in fact helped save the coconut industry in Ben Tre and Tra Vinh provinces. A similar advice regarding the introduction of A. hispinarum was provided to the Philippines in 2005/2006 following the incursion of Brontispa, but was not acted upon. Had this been done, Brontispa problem would have been solved by now.

A respondent from the Phiippines wrote to say that while waiting for a decision on the importation of Asecodes the country has continued work with Tetrastichus, Haekeliana, Metarhizium, Beauveria and Chelisoches. At present, the Brontispa problem in the Philippines is not as critical as it was several years ago, and there is confidence in the development of an IPM program for Brontispa. In addition, insecticide use has been drastically reduced.

Pestnet was reminded that Tetrastichus brontispae was easily recognisable as it is somewhat flattened and, thus, quite distinctive when compared to other members of this genus.

Later still, December 2011.

A report from the Philippines Information Agency of the Presidential Commiunications Operations Office saying that the Philippine Coconut Authority has changed its strategy and that chemcials will no longer be allowed for the control of Brontispa on coconuts, and parasotoids will be used instead. The article reported that 375 mummified Brontispa have been released in southern Leyte, but did not name the parasitoid.

And in March 2012.

In an article in BusinessWorld online, it was said by the principal agriculturist that both chemicals and insects that attack Brontispa are being distributed, and that Tetrastichus (Tetrastichus brontispae) is widely used elsewhere for biological control. The parasitoid is being reared in the town of Polomolok.