Mealybug invades Grand Cayman

The Pink Hibiscus Mealybug, a pest that has caused millions in damage to crops and plants across the Caribbean, has been confirmed for the first time at an undisclosed George Town location.

While it does not pose a direct health risk to humans, the PHM is highly destructive.

It is not known how the pest arrived on Grand Cayman.

The pest, which leaves a distinctive cottony substance on plants, first arrived in the Caribbean in Granada and has since spread to 16 other Caribbean islands the Central American mainland, south Florida and Guyana.

The Department of Agriculture, in collaboration with other government agencies, received confirmation of the infestation from a Florida laboratory specializing in identifying the PHM on Wednesday.

‘We have launched an integrated pest management plan addressing cultural, classical biological, chemical and legal avenues of eradicating the PHM,’ said DoA Assistant Director Adrian Estwick.

The Department is urging residents to immediately report any suspected cases to a newly established PHM hotline.

‘Due to the high risk associated with spreading this pest, we ask that people do not attempt in any way to deal with the problem themselves, or bring us any cuttings or samples,’ said Chief Agricultural and Veterinary Officer Dr. Alfred Benjamin.

Aside from its favoured host, the hibiscus, the PHM is also known to attack 250 to 300 different plant and tree species, including citrus, coconut, sea grape, mango, okra, desert rose and oleander.

So far, the pest has attacked 25 different species on Grand Cayman.

‘It’s not just a nuisance pest,’ said DoA plant pathologist Joan Steer. ‘A PHM colony injects a toxin into its host plant, which kills new growth and withers leaves, eventually killing the plant. On a large scale, the results are devastating.’

The tiny insects have a lifespan of 30 days, and lay 600 eggs at one time. They target new shoots, meaning that the current rainy season provides ideal conditions for the creatures to move in quickly and become well established within weeks.

The pest is also at an advantage on Grand Cayman as it has no local predators that would keep the population in check.

While pesticides may be used in some cases, they have not proved to be highly effective in eradicating the PHM.

Rather, the DoA will use biological control agents. The DoA plans to import a species of parasitic wasps which prey on the PHA and which have been used with great success in other affected regions. They reproduce quickly and have rapid effects.

First off, however, the DoA will be identifying and treating affected plants on a case-by-case basis and performing as much work on-site as possible, including using a portable incinerator to remove and destroy severely affected plants to hinder the spread of the bug.

‘We are asking for the cooperation of the public in working with us to leave affected plants as undisturbed as possible so that our technical experts can deal with each case properly,’ said Mr. Estwick.

The DoA is also enlisting the help of farms, nurseries and garden centres as well as landscape companies to limit the spread of the PHM as much as possible.

‘The PHM is renowned as a great hitchhiker,’ said Dr. Benjamim. ‘It’s very easy for it to spread by catching rides on plants, clothing and gardening equipment. We hope to develop a workable way to cooperate with our partners in these industries in addressing this serious problem.’

The DoA has 60 sentinel sites around the island and Dr. Benjamin said that, due to the severity of the threat, any location where the pest is detected would be immediately quarantined.

DoA officers are continuing to monitor the situation, and the department is in the process of developing emergency regulations to limit international, inter-island and on-island movement of plant materials that can spread the pest. So far, the Sister Islands are PHM-free.

Mr. Estwick was emphatic on one point: ‘We can’t stress enough that all efforts to eradicate this bug will come to zero without the cooperation of our agencies and the public,’ he said. ‘Please report any suspected case to us as soon as you can.’

What to do

To report a possible PHM infestation, call the PHM hotline at: 1-800-534-2847

Signs of PHM:

Crinkled or twisted leaves and shoots

White, cotton-like masses on stems and trunks of plants,

Presence of ants, a sticky secretion, and black sooty mould,

Eventual death of plants

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