A Computerized Acoustical Larval Detection System

A detection system based on the closed organ pipe principle was developed to detect the presence of insect larvae in many postharvest commodities; i.e., grapefruit, oranges, mangoes, papaya and grain. The system detects feeding and moving sounds of larvae and converts the acoustic signal into an electrical signal by means of an acoustic coupler. The signal is amplified approximately 90 dB and then filtered through appropriate bandpass filters. The variables (trigger levels, time intervals of data collections, and sample rates) are controlled by computer software. The computer also stores and analyzes the data.