The Use of Aggregation Pheromone for Monitoring Oryctes rhinoceros Population Dyah Rini Indriyanti 1 , Jeni Eka Lutfiana 2 , Priyantini Widiyaningrum 3 , Ning Setiati 4 {dyahrini36@gmail.com 1 ; wiwiedeka@mail.unnes.ac.id 3 ; ning.setiati@yahoo.co.id 4 } Biologi Department, Faculty of Mathematics and Natural Science, Universitas Negeri Semarang. 1 st floor of D6 Building, Jalan Raya Sekaran-Gunungpati-Semarang 50299-Indonesia 1 Abstract. Oryctes rhinoceros is the main pest that damages the coconut palm by punching holes in its shoot area. The purposes of this study were to monitor the population of O. rhinoceros imago using aggregation pheromones, analyze the comparison of sex ratio, and analyze the other insects captured by pheromones traps. This research was an exploratory study using purposive sampling method. Monitoring O. rhinoceros was carried out by installing pheromone traps using aggregation pheromones in 2 areas (10 samples each). The observations were carried out once a week for three months. The captures of O. rhinoceros imago in the Bondo and Kaliaman Villages were 131 and 83 individuals respectively. Comparisons of sex ratio (male: female) obtained in Bondo and Kaliaman Villages were 1: 1.3 and 1: 0.9 respectively. The other insect species that were attracted by pheromones were Xlotrupes gideon, Rhyncophorus ferruginneus, and Rhyncophorus schach. Keywords: aggregation pheromone, Jepara Regency, Oryctes rhinoceros 1. Introduction Coconut palms (Cocos nucifera) are plants that thrive in coastal areas and some can grow in the mountains [1]. The trade-in coconut meat makes this plant become one of the sources of economic support. Jepara Regency is one of the areas with coconut plantation. However, the coconut palms in that area were damaged by Oryctes rhinoceros attack [2]. The characteristics of coconut palms that are attacked by O. rhinoceros are the form of gaps cut out of the edges of the leaflets. The leaves in the coconut palm become like letter V. The mechanism of O. rhinoceros in damaging the coconut palms is by punching holes in the leaf area of the very young leaves, so that when the leaves have opened there will be damages that will make the leaves become dry and die [3]. Since O. rhinoceros live in the shoots of the coconut palm, it is very difficult to catch them. Therefore, pheromone can be used to attract them to come out. Pheromones are divided into two groups, primer, and releaser [4]. Primer pheromones are pheromones that affect insect physiology while releaser pheromones affect insect behavior of the same species [5]. The types of pheromones used were aggregation pheromones which are included in the releaser pheromone group. Aggregation pheromone is a type of pheromone that is released to attract male and female insects in groups, this type of pheromone is generally produced by insects from the Coleopatera order to defend themselves against predatory attacks ([3]; [6]). ISET 2019, June 29, Semarang, Indonesia Copyright © 2020 EAI DOI 10.4108/eai.29-6-2019.2290443