ANALISIS KEMAMPUAN DAYA RUSAK Neochetina eichhorniae (COLEOPTERA: CURCULIONIDAE) TERHADAP DAUN DAN PERTUMBUHAN ECENG GONDOK (Pontederia crassipes)

Abstract

Eceng gondok (Pontederia crassipes) merupakan gulma air invasif yang mengancam ekosistem perairan tawar di Indonesia. Perkembangbiakan vegetatifnya yang sangat cepat menurunkan penetrasi cahaya dan kadar oksigen terlarut, mempercepat sedimentasi, serta menimbulkan kerugian ekonomi pada sektor perikanan dan pembangkit listrik tenaga air. Metode pengendalian mekanis dan kimiawi relatif mahal serta berisiko mencemari lingkungan, sehingga pengendalian biologis dengan Neochetina eichhorniae menjadi alternatif yang lebih ramah lingkungan. Penelitian ini bertujuan mempelajari tingkat kerusakan akibat aktivitas makan kumbang N. eichhorniae pada daun dan tanaman eceng gondok, membandingkan perbedaan kerusakan antara kumbang jantan dan betina dewasa, serta menilai dampaknya terhadap pertumbuhan tanaman. Percobaan dilakukan di laboratorium dan lapangan dengan variasi kepadatan kumbang. Kerusakan daun diukur berdasarkan jumlah bekas makan dan luas area yang rusak, sedangkan respons tanaman dianalisis melalui parameter pertumbuhan dan laju pertumbuhan relatif berdasarkan biomassa. Hasil penelitian menunjukkan bahwa tingkat kerusakan meningkat seiring bertambahnya kepadatan kumbang dan lamanya paparan. Kumbang betina menyebabkan kerusakan lebih besar dibandingkan jantan, meskipun aktivitas makan individu sedikit menurun pada kepadatan tinggi. Pada skala tanaman, peningkatan kepadatan kumbang secara signifikan memperbesar intensitas kerusakan dan memperlambat waktu penggandaan biomassa, yang menunjukkan tertekannya pertumbuhan eceng gondok. Namun, kepadatan yang digunakan belum mampu menurunkan populasi eceng gondok, sehingga diperlukan kepadatan lebih tinggi atau integrasi dengan metode pengendalian lain untuk hasil yang optimal.

Water hyacinth (Pontederia crassipes) is an invasive aquatic weed that threatens freshwater ecosystems in Indonesia. Its rapid vegetative reproduction reduces light penetration and dissolved oxygen levels, accelerates sedimentation, and causes economic losses in fisheries and hydropower sectors. Mechanical and chemical control methods are relatively costly and pose risks of environmental pollution; therefore, biological control using Neochetina eichhorniae offers a more environmentally friendly alternative. This study aimed to evaluate the level of damage caused by the feeding activity of N. eichhorniae on water hyacinth leaves and plants, compare the differences in damage between adult male and female beetles, and assess its impact on plant growth. Experiments were conducted under laboratory and field conditions using different beetle densities. Leaf damage was measured based on the number of feeding scars and the damaged leaf area, while plant responses were analyzed through growth parameters and relative growth rate based on biomass. The results showed that feeding damage increased with higher beetle density and longer exposure duration. Female beetles caused greater damage than males, although individual feeding activity slightly decreased at higher densities. At the plant level, increased beetle density significantly intensified damage and prolonged biomass doubling time, indicating suppressed growth of water hyacinth. However, the applied densities were insufficient to significantly reduce plant populations, suggesting that higher beetle densities or integration with other control methods are required for optimal management.