Preliminary study on efficiency of different time and light source in light traps for capturing population of adult oil palm bunch moth, Tirathaba mundella (Lepidoptera: Pyralidae)

The oil palm bunch moth, Tirathaba mundella (Lepidoptera: Pyralidae) is a pest of oil palm especially those planted on peat soil. The pest has a short life cycle, approximately 30 days (eggs four days, larvae 16 days and pupae 10 days) and therefore, its population build up rapidly and causing severe damage to the oil palm when proper control is not in place. A research was conducted to determine the efficiency of different design of the light traps in capturing the adult bunch moths and also, aimed to observe the moths’ behaviour in terms of the night flight pattern in the areas with high level of infestation. The study was carried out in two oil palm estates in Sarawak; Location A, Daro and Location B, Sri Aman, from 17-19 July 2018 and 23-25 January 2019, respectively. Six light traps (Location A) and three light traps (Location B) were tested. Night flight activities were recorded for three different intervals; Interval 1 (1925-2125), Interval 2 (2130-2330) and Interval 3 (2335-0135). The result showed that, light Trap 6 was found to be the most attractive in Location A, capturing significantly higher number of moths (mean=38.6667, p<0.05). Whereas, in Location B, Trap 2 recorded the highest number of total individual moths captured but, not significantly different from other designs (mean=18, p>0.05). In terms of the moths’ behaviour, the third interval showed significantly greater number of individual female moths captured compared to the other two intervals in Location A (mean=16, p<0.05). However, in Location B, it was found that the amount of captured female moths in the earlier time intervals (Intervals 1 and 2) was significantly greater (mean=8 and 9.6667 individuals, p<0.05) than final time interval (two individuals), which was opposite to the observations made in Location A. The cause of such behaviour is still unknown and thorough study is needed. Thus, in future study, the data as such additional climatic parameters need to be incorporated (e.g. ambient temperature, humidity, moon phase and wind speed) for further understanding of the behaviours and preferences of the pest. Furthermore, the study also indicates potential application of light trapping as one of the alternatives to the oil palm pest management.