BARBADOS – Efforts are under way to curb the spread of the West Indian Fruit Fly, which is currently affecting Jamaica plums, hog plums, chilli plums and guava trees across the island.
While the existing population is not at an alarming level, Entomologist Ian Gibbs says the unit wants to “keep it that way!”
It is this commitment to pest control which has seen the department limiting the influx of new pests into the island to a mere 13 over the past 7 years. This has the respect of a two-member entomology team from the United States Department of Agriculture (USDA), which visited the island to assist with a biological control program.
Noting that the West Indian Fruit Fly was “virtually all over the island”, Mr. Gibbs underlined that it had not yet reached a level where every plum or guava bitten into, one or two larvae would be found.
“If you look at it on an island level – the population is still relatively low and we want to keep it that way. We want to reduce it as much as possible – that‘s why we opted for this form of control,” he explained.
In reflecting on Barbados’ situation, USDA Entomologist, Dr. John Svinski, admitted that it was somewhat unique, especially when compared with some other islands and Puerto Rico, which has an extremely high fruit fly population.
“It does seem as though there might be some differences here. The population isn’t as high here as it is in other places. There are also certain fruit that this fly isn’t found in here, but it is found in other places. It is always exciting to look at a new population and the differences on the various islands, to discover what might be behind those differences in terms of the environment,” he added.
Describing the ongoing collaboration between the Entomology Department and the USDA as “very rewarding”, USDA, Entomologist, Tim Holler, said the uniqueness of the Barbadian situation allowed for interesting scientific comparisons among countries.
“We are trying to develop the methodologies that we can use to take a biological control program into a country. We can’t just go in and spray, anymore whether it is from an airplane or from a hydraulic sprayer or back pack. We have to go into sensitive areas with these biological control agents. So, when we are working with your Ministry and others we are trying to develop this formula that everyone can use…before the pest population grows. There are long-range objectives associated with the program,” he explained.
Initial talks between the Entomology Unit and the USDA regarding the biological control program dates back to 2003. Since 2006, the USDA has conducted weekly shipments of parasitoid wasps to Barbados, aimed at establishing the parasitoid population at various sites, for eventual distribution to the host fruit fly population.
“At the moment we are releasing one parasitoid species – and hope to introduce a second parasitoid this year, both of which are specific to the fruit fly,” Mr. Holler added.
In giving the rationale for the use of a biological control program, as opposed to pesticides, Mr. Gibbs noted that most Barbadians were not inclined to spray fruit trees in their back yards, due to their size and proximity to their homes, children and pets.
Describing a biological control program as the most practical option, he said: “Once you get a biological control program set up …you don’t have to put in any other inputs. It is environmentally friendly; people friendly and there are no pesticides involved.”
Adding that the parasitoids worked “without anyone knowing or seeing what was happening”, the local Entomologist gave the assurance that they would eventually reduce the fruit fly population.
“It won’t get to zero; you won’t get rid of it. But, the ultimate aim is to bring it to such a low level that it won’t cause any kind of economic damage, or be a significant problem to householders,” he stressed.
Unsure about the USDA’s priorities in coming months, Mr. Holler said the next steps would be to consider whether they would continue to rear the parasitoids, or whether they could be reared on the island.
“I would love to continue – but we don’t know if our priorities are going to make a change,” said Mr. Holler, who expressed the hope that there would be continued collaboration in the near future, even if at the level of consultancies for knowledge transfer in the area of laboratory and field work.
On this score, Mr. Gibbs said it was hoped that at least two members of the Entomology staff could be trained in the area of parasitoid rearing, in the event that the USDA collaboration ceases.
“There might also be the possibility of us rearing them, not only for Barbados, but maybe for other countries in the Caribbean as well,” he concluded.
