Pests won't stop at the borders

Technical Centre for Agricultural and Rural Cooperation

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Technical Centre for Agricultural and Rural Cooperation

Date Issued

1987

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News Item

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Open Access

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CTA. 1987. Pests won't stop at the borders. Spore 10. CTA, Wageningen, The Netherlands.

Permanent link to cite or share this item: https://hdl.handle.net/10568/44666

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Existing plant protection regulations in the Caribbean are not only outdated but suffer from a lack of technical backup. That explains why over the last 25 years these islands have been menaced by many pests that have been introduced from other countries. Pillaging pirates and other outlaws have come back to threaten many countries in the Caribbean. They sneak in by boat or plane, evade customs officials, break into warehouses and rampage through their new found bounty before wreaking havoc with the lives of ordinary people throughout the islands. These modern day plunderers brandish no swords but, seen from close up, are no less menacing with their armour and built-in weapons. They are, in fact, insects, bacteria and diseases that despoil crops and harvests by attacking them on all fronts. To combat such pests, most countries have developed laws and implemented them with more or less effective regulations. It is in this area, however, that many Caribbean countries have fallen behind to the advantage of all sorts of persistent pests. It is not uncommon to see plant protection laws passed over a century ago still on the books. While they may include relatively complete regulations enabling the control of imported vegetation by various sanitation measures, including the destruction of infected shipments, for many islands this is no longer sufficient. Unfortunately, there acoears to be little initiative to update such laws. This leaves those responsible for their implementation a difficult task for which they are, at best, ill-prepared. In some cases, the lack of personnel and technical support means that only a token effort can be made to deal with the problem. The result in many countries is that plant protection measures boil down to a simple bureaucratic procedure: issuing certificates that simply delay exports. Grenada is a good example of the state of plant protection controls in the Caribbean. A law passed in 1891 gives authority to local officials to prohibit or restrict the import of plant material and to order any treatment judged necessary, but it has never been updated. If the situation is not this bad on all the islands, there are various loopholes through which many pests have passed on their way to establishing themselves as local problems. In recent years, some organizations (notably the Caribbean Plant Protection Commission - CPPC - of the FAO and the Regional Programme for Vegetation Protection of the Inter- American Institute for Agricultural Cooperation - IIAC) have made considerable efforts in this direction. Meetings and seminars at both the national and regional level have been organized in close cooperation with agricultural departments of different countries in order to promote better plant protection controls. Direct technical support has also been given to help update and enforce regulations. As a result of an IIAC study on phytosanitation measures in various Caribbean countries, a certain number of common problems have been identified: insufficent records, inexperienced personnel, outdated legislation, and a general lack of both material and staff. Some of these obstacles are now being overcome thanks to the various programmes noted above, but much remains to be done To deal effectively with this problem, one must first of all know how the pests in question arrive. Most of them are brought in on vegetable matter, notably live plants, fruit and grains. Studies in the Caribbean have identified three major vectors. The first is the use of exotic HYV seeds, seedlings, cuttings or tubers. The second is the importation of staple foods needed to complement the country's food supply deficit. Finally, there is the exchange of agricultural products within the region. Whether in the form of vegetable matter or another agricultural product, processed or not, all of these vectors run the risk of introducing serious plant diseases or infestations. Experience in some ACP countries has shown that, if properly applied, plant protection measures that are constantly revised to keep up with modern transmission patterns can reduce such risks. National measures, however, will never be enough to deal with these 'pests without borders'. We now know that effective international control measures must do more than try to keep pests out of uninfected countries. Attention must also be given to reducing the export of such problems. As with human health, sanitary measures must be taken on both sides: by protecting others, one protects oneself and by exporting only uninfected products, one reduces the likelihood of importing infected products in the future. This principle is particularly valid in the Caribbean where there is a constant flow of products between the islands. The lesson has been well learned in the Barbados, St. Vincent and Antigua. Unlike their neighbours, these countries have not suffered from an infestation of Anastrepha on fruit. In order for them to keep this pest out, they must ensure that control measures be taken beyond their borders. Their best allies are thus the inspection services of exporting countries which must be able to ensure that only uninfected products are shipped. Even in regions where such controls are adequate and applied effectively by all countries concerned, new pests have still been introduced. As recent studies have confirmed, the loopholes and poor enforcement of regulations are not the only cause for the failure of plant protection measures. Of the world's 350 or so major agricultural pests listed by the Commonwealth Institute of Entomology, more than 60 % have been introduced. This has led to the 'inevitability theory' which holds that 'all pests will eventually get to all parts of the world because phytosanitary controls can only retard their spread'. Unfortunately, some specialists are beginning to agree. For evidence, they cite the recent introduction of a citrus scab in Florida, a mango seed beetle in Guadeloupe, Martinique and St. Lucia, and the slow but steady spread northward of the African killer bee despite draconian protection measures. A recently discovered element also supports this thesis: it seems that natural vectors, such as winds, storms and ocean currents, also spread diseases and insects. Hurrican Allen, for example, is blamed for having introduced thrips (Fulmekiola serrate) into the Caribbean. Previously unknown in the region, it had disastrous effects on sugarcane plantations in Guadeloupe and the Barbados before moving on to Guyana and Trinidad. Another problem in Guyana's plantations is a smut disease whose spores appear to be carried by the wind over the Atlantic from West Africa. In this case, no number of laws or inspections would be effective. Even if after all precautionary measures have been taken some pests still manage to reach another country, the battle is far from over. One can still fight a rearguard action to stop them from spreading. It is at this point that good technical support can play a pivotal role. Unfortunately, few phytosanitary services in the Caribbean have access to such facilities. This shortcoming was primarily responsible for the spread of moko disease among bananas. Introduced to Grenada earlier this decade, it has resulted in over 2 million dollars worth of losses and poses enormous risks to the banana industry in the region. As the closest country, St. Vincent is at the greatest risk due to the fact that the Grenadine archipelago acts as a land bridge between the two larger islands. The lack of a good plant protection service was also responsible for the 1965 invasion of a sugarcane beetle (Diatraea centella) on the island of Abaco in the Bahamas. It was introduced by sugarcane seeds brought in from Guyana. An effective protection service could at least have avoided its spread once it was introduced. If it is easy to evaluate the losses caused by such pests, it is much harder to predict the economic impact of identified threats and thus to gauge the investment warranted to prevent their spread. The cruciferae moth (Plutella xylostella). for example, was discovered for the first time in Trinidad in 1945 but it caused little damage until 25 years later. The cherry beetle was first observed in coffee plantations in 1978 in Jamaica, but has not been noticed anywhere else. On the other hand, sugarcane smut and rust, identified in 1974 and 1978 respectively, spread like wildfire through all Caribbean sugarcane plantations as well as those in Central and South America. The best protection against such pests remains prevention. First of r all, every effort must be made to : stop them from leaving or entering countries. Once introduced, eradication and treatment measures are both complicated and very costly. It took no less than 27 months and 176 million dollars to control the 1980 Mediterranean fruitfly epidemic in California. It is thus easy to understand why the Barbados banned the import of mangoes from St. Lucia when mango seed beetles were discovered there in 1984. Many measures are now needed to improve plant protection in the Caribbean. The first seems to be better information. Whether designed to evaluate the risks of spreading pests through internal circulation or international commerce, studies of transmission methods will be very useful. Unfortunately, even basic data such as lists of existing pests in these countries is not always available. In addition to studies on the risks and modes of infestations, analyses of the economic impact of introduced pests are needed. Finally, it must be remembered that phytosanitary control personnel can only help to ensure the food security of their countries if they are given the necessary training and technical support. BIBLIOGRAPHY: Adapted from: 'Plant quarantine in the Caribbean: A retrospective view and some recent pest introductions' by G. V. Pollard in the FAO 'Plant Protection Bulletin' Vol 34 N° 3 1986