Existing and potential pests

This post is also available in: Dutch.

The independent scientific research bureau Imares, located in Wageningen in the Netherlands, already warned in March of this year of the possible arrival of the Agave Weevil. This warning comes from a report from the Institute which was published in that month and was drafted by scientists Gerard van Buurt and Adolphe Debrot. The Agave Weevil was first discovered locally about two weeks ago at Coral Estate by a local gardening company, but a day later the widespread dispersion of the animal in other parts of the island was confirmed, however. The Agave Weevil causes heavy damage because it destroys both imported and indigenous species of agave and thus impacts the food supply of local wildlife in the dry season.

The Red Palm Weevil (Rhynchophorus ferrugineus) already caused quite some commotion….

In March, Imares published a report titled “Introduced Agricultural pests, plant and animals diseases and vectors in the Dutch Caribbean, with an alert species list”. On the alert list the Agave Weevil was included, as well as other potential hazards such as the Mango Seed Weevil, that has mango seeds as a food source, and the Palmetto Weevil that affects palm species which are used for landscaping. Other species on this lists are the ‘Formosan Subterranean Termite’ (Coptotermes formosanus), which not only feeds on dead but also on living wood and is difficult to combat, the Red Fire Ant (Solenops invicta) that can pose a direct hazard to humans, and the Asian Tiger Mosquito (Aedes albopictus). The report also lists already introduced pests such as the Cuban garden snail, which might turn into a big problem for agriculture, the Varroa Mite that infects honey bees and makes them very aggressive, and the Yellow Fever Mosquito.

In total, the report lists 47 exotic pests, diseases, parasites and pathogens that are already established on one or more of the Dutch Caribbean islands, Aruba, Bonaire, Curacao, Sint Maarten, Sint Eustatius and Saba. “The majority of agricultural pests are not highly host-specific and will also target native plants and/or animals. This makes it very difficult to eradicate and control the pests once established. Prevention and early eradication is the key,’ according to Imares in the summary of the report.

Strict control is necessary

According to the research institute, the main way exotics are brought in to the islands is by means of the import of unsterilized soil and plant material in shipping containers, as well as by means of the import of ornamental plants, but also aviation in general. The institute estimates that the economic costs due to the damages and management interventions annually amount to millions. ‘The most economically costly invasive species is the Yellow Fever Mosquito, Aedes aegypti, a pest and pathogen that is closely associated with humans.’
‘In the Dutch Caribbean, the introduction of invasive pests still takes place at a high pace and measures are urgently needed to reduce and minimize future costs and risks in terms of economy and health.’

The research team therefore advises to restrict and monitor the import of ornamental plants, most of which can also be grown locally without the risk of new introductions. It is also recommended to restrict the import of unsterilized food items, to implement a more watertight control system and to apply prophylactic gasification to imported containers. Strict veterinary control on the import of animals is the next step. This requires a greater awareness, supporting legislation, cooperation between customs agents and importers and the presence of a biosafety team with the authority and resources for fast and adequate action.

The peculiar snout that paves the way for the weevil’s eggs. After these hatch, the infected palm is in serious trouble, because the ravenous appetite of the larvae will turn the palm innards into a tunnel system. If no drastic counter-measures are taken, that is.

Added to the report is a preliminary list of 21 potentially invasive species. This list is based on experiences from other Caribbean countries and existing trade routes and also takes into account whether the species can survive in arid climates like ours. This list includes only the pests and diseases that are important for agriculture, not invasive species that might pose a problem for ‘normal’ plants and animals, and will be periodically updated. It is a handy tool for biosafety teams to draft management plans and to ensure that the most effective insecticides are kept in stock in order to be readily available if an infestation occurs.
‘The introduction of the Red Palm Weevil in Aruba and Curacao was totally unnecessary. It was already known that palms from Egypt were infected and most European countries already banned the import of palms from the Middle East. A simple import ban could have been enough to keep out the species. The problem is that the ones who gain from unrestricted imports are usually not the same people as those who are suffering from the consequences. The palms could be bought in Egypt for $ 300 each and were sold locally for $ 5500 each. That amounts to a high profit margin, even after deduction of transportation costs, import duties and customs costs. And while some importers lost palms, a new market evolved for certain insecticides as well as a new market for other landscaping trees,’ according to Imares.

Male Shiny Cowbird (Molothrus bonariensis), also ‘blacklisted’

At the end of 2011, the same scientists published the report ‘Exotic and invasive terrestrial and freshwater animal species in the Dutch Caribbean‘. This report documents and discusses 61 introduced species currently living in the wild or semi wild on the islands, including 12 exotic species of mammals, 16 species of birds, 13 species of reptiles, 5 species of amphibians, 2 species of freshwater fish, 3 species of insects, 2 species of snails and 8 exotic worms. This list does not include species listed in the report from March.

To prevent other introductions to the islands, and to control the exotics and invasive species already living on the islands, the researchers advise to implement ‘Invasive Species Management Teams (ISMTs)‘ on all the islands to assist the customs in the identification of unwanted species, and to avoid the introduction of unwanted species. In addition, the team should assist in the process of eradication of plant diseases and invasive species, and give regular presentations to the customs, pest control and gardening companies, nature groups and the general public. ‘It is very important to maintain contact, for public involvement and feedback are key in order to be able to identify new problems rapidly. In addition, a list of potential hazards should be compiled and updated regularly, the team must keep in touch with all partners on the sister Islands, as well as regional organizations such as FAO, CABI and USDA / Aphis. The team should also compile a list of species for which import should be banned. Initiatives to draft legislation and implement the teams should be takes as soon as possible, and the teams should be embedded well in policy frameworks. The first step should be: the definition of an ‘Invasive Species Strategy and Action Plan (ISSAP)‘, is what the report states.

The reports can be downloaded from the Imares site: report 2011, and report March.

About Michelle da Costa Gomez

2 Responses to “Existing and potential pests”

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  1. rob wellens says:

    Hello michelle, nice to see the shiny cowbird is shown in this article. I live in julianadorp, curacao, and love watching the birds in my garden that come feed and drink on my feeders. One day i spotted this beautiful black bird in my garden and tried to find out more about it on the internet. I was shocked to read what this pest had done to other caribbean islands birdlife. Soon i started to see proof of the devastation this bird is capable of. I saw it lay eggs in nests of other bird species, i saw yellow trupial feeding a young shiny cowbird as if it was their own. Soon i had over 25 shiny cowbirds in my garden chasing away the other birds. A friend of mine came up with an idea to catch them. We caught over 200 in my garden and put them to sleep. Other birds started to grow in population back, we even experienced an invasion of young orange trupial. So many that they became a problem and we had to catch a number of them and let them go in other parts of the island. The shiny cowbirds became scarse for quite some time, but lately they seem to have found their way back into my garden and start to chase even the prikichis away. Problem is this time i have hardly time to catch them my proven way and even then; this is one very smart bird, in some extend smarter than its relative, the trupial. Michelle, one thing always was a point of concern to me in telling people to catch the shiny cowbird and put them to sleep. People seem easily to confuse this bird with the ani or chuchubi pretu and the carib crackle…. and might catch the wrong bird.

    KEep up the good work though!


    Rob, parallelweg 15


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