Exploration and Evaluation of Potential Dominant Predators as a Candidate for Biological Control Agent Neotoxoptera Formosana (Takahashi) (Hemiptera: Aphididae) Onion Plants (Allium Fistulosum L) in Bali

Neotoxoptera Formosana Takahashi (Hemiptera: Aphididae) is an important pest in leaf onion plants and is also the cause of latent transmission of viruses in onion plants which currently has spread in various regions such as West Jawah, Central Jawah, Sumatra and Bali with attack intensity between 20 to 100%. The purpose of this study is to obtain predators that are effective in controlling N. formosana in all types of onion plants, especially leaf onions (Allium fistulosum L.) in Bali. The potential as a predator of N. formosana was carried out in two experimental stages, namely predator exploration, preference tests and functional responses to dominant predators. Predator exploration was conducted using survey method. The research was conducted in three districts in Bali (Denpasar, Tabana and Bangli) from May to July 2025. The exploration found 12 predator species, with Menochilus sexmaculatus (Coccinellidae) and Oxyopes salticus (Oxyopidae) as the dominant predator species. Preference tests showed that M. sexmaculatus larvae had a high predation rate of 8.83 per day, on N. formosana instar 4 and functional response tests showed O. salticus had a high predation rate of 44.00 within 24 hours at a prey density of 60 N. formosana instar 4, with a type I functional response pattern. Menochilus sexmaculatus (Coccinellidae) and Oxyopes salticus (Oxyopidae) are potential predator species in biological agent control of N. formosana aphids on spring onion plants in Bali.