The Challenge

To develop a system for detecting the presence of weevil in mango trees in order to protect them from weevil infestation as well as to medicate them at the earliest. The weevil infestation in mango trees causes serious problems and they decrease the yield of the mangoes produced. The farmers find it very difficult to trace the infected tree in their own fields. The present method (current scenario) is visual inspection where in a farmer has to see for any symptoms like oozing out of an viscous brown fluid, extrusion of the chewed up fibers through the holes in the trunk of the tree, longitudinal splitting of the leaf bases and withering of the central spindle. In severe and later stages of the infestation the sound of gnawing and the breaking of fibers could be heard in silent environment. This system will detect the presence of the weevil inside the mango tree at the earliest stage possible by using the acoustic emission technique.

The Solution

The proposed system will detect the presence of the weevil in the beginning stages of tunneling the tree. The weevil, when it bites the tissues of the tree, liberates certain high frequency stress waves and these waves are above the audible range i.e., > 20 kHz. An acoustic emission sensor is fixed to the tree and it is monitored using LabVIEW software. The frequency of the biting of the weevil is found earlier and it the sensor picks the frequencies from the tree and when it is matched with the frequency above said then there will be an indication in the front panel window of LabVIEW

Implementation

The method of working is based on simple steps. The signal from the acoustic emission sensor is coupled to the amplification circuit. After amplification it is filtered to remove the unwanted signals and then the filtered signal is fed to LabVIEW program where processing is being carried out. The frequency of the input signal is compared with the frequency specified in the program and if they match, it shows the presence of the weevil

Benefits of the Application

The advantage of using this system is that it is able to detect the presence of weevil at its initial grub stage. But the present method(current scenario)of detection is possible only after 35% of damage caused to the tree. At that stage controlling the pest will not be effective. Also the annual yield drops drastically even though it is detected after 35% damage.

The indication of the presence of the weevil will help the farmers identify the affected trees so that the necessary steps could be taken to medicate the trees and to prevent them from further infestation. Hence, a new system which is highly flexible, cost effective and simple has been developed