Harnessing Flowering Bund Plants Through Ecological Engineering to Improve Biological Control of Tungro Virus Vectors in Indonesian Rice Fields Agroecosystem.

Abstract

Ecological engineering (EE) has emerged as a promising strategy for managing insect pests in rice ecosystems by reducing dependency on chemical pesticides. However, the survival of parasitoids and predators in rice habitats is often limited due to a lack of refuge and food sources. While pesticides remain the primary method used by farmers to control green leafhoppers (GLHs), the main vectors of the tungro virus, their overuse poses serious risks to both environmental and human health. This study was aimed at evaluating the impact of EE on the population dynamics of GLHs and their natural enemies, the suppression of tungro virus infection, and the maintenance of rice yield. Field experiments were conducted in Sidrap, Indonesia, across three dry seasons (2016, 2017, and 2021) using three treatments: EE with biopesticide (T1), prophylactic insecticide use (T2), and untreated control (T3). The GLH population was significantly lower in T1 compared to T2 and T3, while natural enemy abundance (e.g., spiders, parasitoids, and predatory beetles) was highest in T1, particularly during later growth stages. Tungro incidence was lowest in T1, moderate in T2, and highest in T3, exceeding 13% in control plots. Despite differences in pest pressure and virus infection, rice yield did not differ significantly among treatments, with the highest yield (≈10-11 t/ha) recorded in 2021. These findings suggest that habitat manipulation through EE can suppress tungro vectors, enhance natural enemy populations, and sustain rice productivity without relying on chemical inputs.