November 26th 2011
A New Invasive in St. Lucia Ivy Gourd/ Scarlet Fruited Gourd (Coccinia grandis)
By Virginie Sealys

(Photo) Ivy Gourd

Introduction

Alien invasive species can be any living micro-organism, animal or plant. “Alien” means not naturally found in St. Lucia. “Invasive” means they can spread unchecked and are difficult or impossible to control. Such alien species can compete with indigenous species for food, habitat, etc. causing a reduction in numbers or even extinction of local species. In this way, if they spread outside their natural past or present distribution, they can be harmful to our life forms including wildlife in many ways.

Examples of invasive species introduced in St. Lucia include African Tulip (Spathdea campanulata), Casuarina (Casuarina equisetifolia), mongoose, the alien iguana at Soufriere, thrips (Holopothrips iniquilinus) which causes the curling of white cedar leaves and the bont tick (Amblyomma variegatum) that feeds on a number of domesticated animals including cattle, sheep, goats, horses and dogs.

One other species recently identified in St. Lucia is ivy gourd (Coccinia grandis). It is a vine that is capable of smothering forests and desirable plants. Growing aggressively and vigorously, this vine forms a dense canopy smothering vegetation, grounds, fences, utility lines and forests in low elevation areas. This thick covering chokes out the sunlight to anything below.

The challenge with alien invasive species is the high cost to reduce or eliminate it once that species is established in the country. For example in the United States it costs $138 billion on a yearly basis to control invasive alien species. The best strategies for their management are (1) to prevent the entrance of these species or (2) to eradicate them before they are established within the country.

The ivy gourd has established itself in parts of Babonneau and at Morne Fortune and may have spread already to other areas yet unknown to us.

(Photo) Pathdea campanulata

Biology

The vines grow about 3metres long. Ivy gourd flowers from August to September.
The plant is not self-fertile. It has tendrils, ivy-like leaves, white bell shaped flowers and red fruit 1-1/2" long.

Ecology
The plant prefers light (sandy), medium (loamy) and heavy (clay) soils, well-drained yet moist. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. Only female plants bear fruit. The flowers are white with 5 petals. This plant is very easy to grow from any method other than seed. Cuttings grow roots very easily. The main root has to be pulled out to keep it from growing back.
Coccinia grandis is a pest plant in Hawaii, an aggressive weedy vine from Africa, Asia, and Australia. From its ecology one can tell that it grows in a wide range of habitats.

The Way Forward
? Site visits are to be done to monitor regeneration of plants in the areas where they have been located.
? Increase awareness of this plant and its impact within the Ministry of Agriculture, Lands Forestry and Fisheries and the public.

Coccinia grandis is a threat to our indigenous plants and we need to take the best step in protecting our nation natural resource.

Let us be on guard to protect biodiversity in St. Lucia from alien invasive species.

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