Wasps released

The first of 5,000 parasitic wasps, were recently released at several George Town sites, where pink hibiscus mealybug infestations had been confirmed.

‘The wasps specifically target the pink hibiscus mealybug and pose no danger to people or animals,’ said visiting US Department of Agriculture Entomologist, Dr Amy Roda, who examined the four confirmed infested sites in Grand Cayman, states a GIS press release.

She noted that, although the biological control method takes time, it is the most successful method to date.

‘Local observers monitoring the situation should begin to see measurable reductions in the PHM population in another three months.’

Referring to our tropical climate, which is ideal for this method to work, she added that ‘The Cayman Islands are very lucky.’

Ms Roda explained that the pink hibiscus mealybugs are parasitized by the wasps, which lay an egg in the mealybug. The egg hatches and as the larvae grows and feeds, it kills the mealybug host and produces a mummy from which a new adult wasp emerges.

Studies across the Caribbean have proven that the release of parasitoid wasps have lead to an over 90% reduction in PHM and are very effective for long-term control.

Ms Roda, who was invited by the Cayman Islands Department of Agriculture to help ensure the effective release and monitoring of the parasitoid wasps locally, has extensive experience in the biological control of invasive species. She has worked on control strategies for the pink hibiscus mealybug in Florida, the Caribbean and Central America for the past several years.

During her visit (17-21 July), Dr. Roda worked closely with the DoA technical team to refine strategies for the effective release and monitoring of the biological control agents under local conditions and develop criteria for the selection of suitable study sites. She provided additional training to DoA laboratory staff in techniques for the identification of wasps from field samples of parasitized mealybugs and also used the opportunity to update staff on the latest developments, strategies and results of the ongoing PHM biological control programme in South Florida.

Minister of Agriculture, Hon. Kurt Tibbetts thanked the USDA for providing assistance through Dr. Roda and said he believes the infestation was discovered in a timely manner.

Ms Roda told Mr Tibbetts she believes that the PHM, at this time, is primarily limited to its preferred host – hibiscus. In addition, Mr. Tibbetts expressed confidence in his ministry’s management of the situation, stating, ‘I am content that we will be very successful in controlling the infestation.’

Mr. Tibbetts also stated that DoA staff will continue to release the wasps for the next six months, and that periodic assessments will be done to measure the effectiveness of the programme. This information will help the DoA team determine if and for how long the release programme should be extended.

Present for the release of the wasps were Mr Tibbetts; Dr Roda; the ministry’s Permanent Secretary Kearney Gomez, and its Administrative Officer Leyda Nicholson-Coe; and DoA Media Liaison Officer Brian Crichlow. Other DoA and ministry staff were also in attendance.