Providing practical information to help you protect your farm from biosecurity risks

Chocoholics celebrate eradication of pest

February 7, 2014
Cocoa pod borer damage

The cocoa pod on the right shows the damage caused by the borer.

For more than a decade producers have successfully been growing cocoa trees in Far North Queensland and in 2011 the first chocolate made from commercially-grown Australian cocoa hit the market.

2011 was also a notable year for the cocoa pod growers of Far North Queensland as this was the year the exotic plant pest cocoa pod borer (Conopomorpha cramerella) was first identified in Mossman.

It was a setback for the fledgling boutique Australian chocolate industry, but the area has now been declared free of the pest.

According to Brad Siebert, Manager for Biosecurity Planning and Implementation at Plant Health Australia, it’s one of many Australian biosecurity success stories.

“This successful eradication was achievable as the pest was found and reported early,” said Mr Siebert.

Some local canegrowers in the area had diversified into producing cocoa pods for making chocolate. Cocoa plants only grow in a hot, wet climate and flower all year round, so the pods can be harvested multiple times a year, providing a steady income for producers.

“A single property was affected by the pest which was detected early before it had a chance to spread to other properties in the area. Officially, it was considered ‘technically feasible’ and ‘economically beneficial’ to eradicate,” he added.

The successful eradication depended on breaking the month-long lifecycle of the borer. The caterpillar phase infects the pod, but not the rest of the cocoa plant. They then pupate in a brown cacoon in leaf litter. The resulting mosquito sized adult moth, which lays eggs on the pods, only survives for one week and is a poor flyer.

“The eradication plan involved a spraying regime and the continual stripping of pods from the trees, which were pruned but not entirely removed. Collection of pods breaks the lifecycle and makes it possible to eradicate the pest,” said Mr Siebert.

The area between trees was cleaned of grass and leaf litter that could harbour the pupae. Restrictions  were also placed on the movement of plants, plant material and machinery off the infested property.

“Monitoring for the pest using pheromone traps continued for more than two years after the initial detection. Biosecurity authorities are now satisfied that the area is free from the pest and have recently declared it to be officially eradicated,” concluded Mr Siebert.

With only a one month life cycle, the outcome could have been very different if the pest had managed to spread further than the initial property.

Through early notification of something unusual on the pods, the fledgling Australian chocolate industry now has a chance to realise its full potential without major long-term ongoing costs to control the cocoa pod borer.