A new pest is causing concern for officials in the Ministry of Agriculture, Food Fisheries and Water Resource Management.
The Erythrina Gall Wasp is posing a threat to the Immortelle and Wiliwili trees found around the island. Immortelle is used as an ornamental tree, while the Wiliwili is utilised mostly by farmers as a “wind break”. Both species are members of the Erythrina family.
The ministry’s entomologist, Ian Gibbs, said that the wasps were discovered in Barbados late last year.
“It is a very tiny insect but it does a tremendous amount of damage. It lays its eggs into the tiny shoots and into the leaf tissue and when the eggs hatch and the larvae begin to feed, they cause wart-like protrusions on the leaves and the shoots grow abnormally. If the infestation is high on a given tree, it can really impair the growth of the tree,” he explained.
Difficult to control
Gibbs said the wasp was a difficult pest to control. However, he added that the ministry recommended a combination of “mechanical” and insecticidal measures to control it. He advised persons who have affected trees to remove the damaged areas and burn them. If burning is not an option, he suggested that the affected parts be placed in large plastic bags which should be tied and left out in the sun for a week or more before disposing of them.
In addition, the tree should be treated with an insecticide that containing imidachloprid.
“You apply it to the surface of the soil under the tree and you water it well. It is systemic, the tree takes it up via its roots, translocates it to all of the parts of the tree and it will then control any attack by this pest.
“But it is difficult to control. Quite a few countries have seen a very high incidence of attack on their Erythrina trees, places like Hawaii and Florida,” Gibbs explained.
Preventing such pests from entering the island was virtually impossible, he noted, with increasing trade and visitors to the island. Gibbs added that it was quite difficult to detect “a few eggs” of a given type of insect among a shipment of hundreds of plants.
The problem was compounded, he said, by persons bringing plants into the island illegally.
“They may see a plant that they like and they might snip off a piece and put it in their pockets or in their bags and that comes through. That is something we try to make the general public aware of. Please do not do that.
“There is a standard method if you want to bring in plants. You can visit our Plant Quarantine section in Crumpton Street, [The City] and fill out a form stating which plant you want to bring in and they will tell you if you can bring it in. And the reason for that is that we want to keep Barbados free of these unwanted pests,” he emphasised.