Population Dynamics of White Grub, Holotrichia seticollis (Coleoptera: Scarabaeidae) in NW Himalayan Regions of India

Population dynamics analyses of Holotrichia seticollis Moser, 1912 (Coleoptera: Scarabaeidae) through the light trap, pheromone trap and in-situ sampling were conducted in Uttarakhand, Himalayas for three consecutive years (2019-2021). The three chemical synthetic attractants tested for their efficacy in attracting and trapping the adult males of H. seticollis showed that the most potent species-specific synthetic attractant was methoxybenzene that trapped up to 14.58 beetles/day, followed by diethyl benzene (1.29) and 1, 4-diethyl benzene (0.53). Second fortnight of June was peak period for the emergence of H. seticollis. The maximum trap catches were between 21 to 26 standard meteorological weeks (SMWs), while a sharp decline in population after 26 SMW in both the traps as well as in-situ collection. However, the light trap catches were extremely low in comparison to pheromone traps, thus indicating that, although H. seticollis is a nocturnal insect, but it was not positively phototactic. Therefore, pheromone traps can be successfully used for monitoring pest abundance of H. seticollis at field level and also assist in drawing accurate risk maps for designing and implementing sustainable and eco-friendly integrated pest management programs in the Indian Himalayas.