Bioinformatics to protect coconut trees from weevils
HE COCONUT RESEARCH INSTITUTE, SRI LANKA
in Collaboration with
KINGS COLLEGE LONDON
BIOINFORMATICS FOR PEST CONTROL
What are red palm weevils and what do they do to coconut trees?
The red palm weevil is the main pest of the palm tree. They lay their larvae inside the tree and can breed at an astronomical rate. The larvae start by eating the inside of the tree. The tree will eventually show signs of bleeding and when this happens all that can be done to treat the tree is burning. Farmers also sometimes try painting the tree in diesel to kill the larvae, this method is unproven.
What does this mean for coconut farmers?
For Sri Lankan coconut farmers red palm weevils are a kind of silent killer (unless you have the detector), for Sri Lankan farmers it is very hard to know what trees they are living in until it is too late. Once they have a foot hold in a plantation they can easily spread to multiple trees meaning that the farmer can end up loosing many trees in one go. Each tree produces around 60 coconuts per year, however that is just the tip of the iceberg. Every part of the coconut tree can has commercial value to farmers, therefore when they lose a tree it is very distressing. It takes 5 years for a coconut tree to reach maturity so the lost of a tree is incredibly significant to low income farmers with small holdings.
What is the current solution?
Dr Thrish Nanayakkara, who has many friends and family in Sri Lanka started working on a solution several years ago after a friend asked him if he could find a way to solve this problem. Thrish, who has a background in robotics rather than parasitology approached the problem from a new angle to those who had already tried to tackle it. He decided not to read a single paper on parasites and started working on the problem with a fresh set of eyes. First, he looked at the mechanics of the red palm weevil and discovered they made a very rhythmic crunching sound as they chowed down on the palm tree from the inside. He wondered whether this distinctive sound could be used to identify the red palm weevils at an early stage but he had a problem, Sri Lanka is tropical and there is a lot of background noise, particularly from birds and other insects. So Thrish then brought in some computer science to the solution and built a device that could amplify the crunching sound the weevils made.
How does the solution work?
It’s a bit like how a doctor uses a stethoscope, the doctor is trained to be able to detect abnormal sounds in the heart. The device requires a similar level of human interaction, the farmer is given an example recording of what to listen out for and then uses the device to amplify the sounds inside the tree and he listens out for the red palm weevils just like a tree doctor. Below is a short video clip showing a farmer using the device.
Why is this project important?
An estimated 10% of palm production is damaged by red palm weevils, Sri Lanka alone produces over 2 million tonnes of coconuts per year. Many of the farmers are small holders with low incomes and for them every coconut counts. The annual damage in Sri Lanka is estimated to be around £15million and causes significant economic and social problems.
Prior to Dr Nanayakkara invention there has been no reliable sensor to detect this pest in the larvae stage. By detecting it in the larvae stage it means chemical treatments can be applied rather than the alternative of finding the red palm weevils at a late stage and having to burn down the whole tree. Coconut trees take 5 years to reach maturity so prior to the detector the farmers just have to hope that they do not have weevil larvae inside their trees.
Dr. Nanayakkara, in collaboration with the Sri Lanka agricultural council has already developed a portable electronic device that has been found to be very accurate at detecting larvae at an incredibly early stage. This device has already been recommended by the coconut research institute (CRI) to more than 5000 farmers in Sri Lanka as the best detector available.
Why is it necessary to build an app if there is already a detector?
Cost. The cost of the detector is £40, this is very expensive for Sri Lankan farmers, to put this in perspective this is 8000 rupees which in rural parts of Sri Lanka could be a whole months rent. Despite this, the majority of Sri Lankan’s have smart phones and the device that Dr. Nanayakkara has developed lends itself perfectly to being integrated into an app that could be downloaded for a few pounds.