Year: 2025 | Month: December | Volume: 12 | Issue: 12 | Pages: 526-533
DOI: https://doi.org/10.52403/ijrr.20251256
Utilization of Biological Control Agents Neochetina spp. Beetles in Control of Water Hyacinth (Eichhornia crassipes (Mart.) Solms) in Lake Tondano, Minahasa Regency, Indonesia
Maxi Lengkong1, Vivi B. Montong1, Daisy S. Kandowangko1
1Department of Plant Pest and Disease, Faculty of Agriculture, Sam Ratulangi University, Manado, Indonesia
Corresponding Author: Maxi Lengkong
ABSTRACT
Lake Tondano, located in Minahasa Regency, North Sulawesi Province, holds strategic ecological, economic, and socio-cultural importance, but is currently facing a serious threat from the invasion of water hyacinth (Eichhornia crassipes (Mart.) Solms). As an environmentally friendly alternative to mechanical or chemical control, the use of biological control agents has become an increasingly attractive option. One biological control agent proven effective against water hyacinth is the Neochetina spp. weevil, consisting of Neochetina eichhorniae and Neochetina bruchi. These beetles are highly host-specific and attack water hyacinth during both larval and adult stages. This study aimed to evaluate the destructive ability of Neochetina spp. as biological control agents on water hyacinth growth in Lake Tondano. The experiment was conducted in the field using a Randomized Block Design (RBD) with five treatments and three replications. The treatments consisted of 0, 10, 30, 60, and 90 adult beetles released onto 100 water hyacinth plants. Results showed that feeding scar on leaves increased consistently from Observation 1 to Observation 3, and the severity of damage was directly influenced by the number of adult beetles released. In Observation 1, damage ranged from 5.66 (P1) to 39.33 (P5), while in Observation 2 it increased from 2.0 (P1) to 2658.66 (P5), and in Observation 3 from 11.0 (P1) to 2937.66 (P5). Similar patterns were observed for leaf scraping damage, which also increased with beetle density. Furthermore, water hyacinth biomass decreased significantly as the number of Neochetina spp. adults increased. This reduction resulted from tissue damage by adults, internal feeding by larvae, and subsequent physiological stress on the plant. Overall, the decline in biomass demonstrates the potential of Neochetina spp. as effective biological control agents and supports their role in promoting healthier aquatic ecosystems.
Keywords: Neochetina spp, Eichhornia crassipes, feeding scar, biomass.
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