The progress in the research of AE detection method of old house borer larvae (Hylotrupes bajulus L.) in wooden structures

Abstract

The paper presents the automated analysis of the presence of the old house borer larvae (Hylotrupes bajulus L.) in the wooden constructions. The insect activity was observed in a temperature of 28, 30, 32, 34, 36, 38 and 40 °C in a Scotch pine wood j (Pinus sylvestris L.). That activity has been evaluated by 3 criteria: the number of 5-minute periods with the presence of larvae boring wood sounds confirmed, the number of wood bites and the average sound energy during the larva's wood carving. The comparable results showing larvae change in activity have been achieved using these 3 methods. This approach has proved high efficiency of old house borer larvae detection in the temperatures up to 34 °C, nevertheless for temperatures exceeding 40 °C it is not applicable. The exposure to 40 °C for a week did not cause the death of large larvae. It's highly possible that they can return to a wood carving after the detracting factor has ceased. The sound energy produced during the old house borer larvae's wood-drilling is expected to make the AE method useful for detection of old house borer larvae's in large-size constructions.