Miaoli District Agricultural Research and Extension Station Mass-Produces Natural Predator 'Black Egg Wasp' to Effectively Control Organic Rice Pests in Hualien-Taitung

Central News Agency, Taipei, May 22. Organic rice fields in the Hualien-Taitung region have been plagued by the 'rice black bug' in recent years. The Ministry of Agriculture's Miaoli District Agricultural Research and Extension Station (DARES) has developed mass-production and release techniques for the 'black egg wasp,' a natural predator of the pest. Over the past three years, millions of these wasps have been released, effectively suppressing the infestation and allowing organic rice yields to recover.

The Ministry of Agriculture issued a press release today stating that the rice black bug was once listed as one of the top five rice pests in Taiwan during the Japanese colonial period. In recent years, due to the expansion of organic farming areas, it has once again invaded the Hualien-Taitung region.

Shih Chia-hung, Director of the Miaoli DARES, stated that the rice black bug was once considered a potential pest due to the widespread use of pesticides. However, as over 100 hectares of rice fields in Guanshan Township transitioned to organic farming, the rice black bug ravaged the area between 2021 and 2022, causing yields to plummet by as much as 74%. Furthermore, the adults often flew into nearby residences after the rice harvest, causing significant disturbance to local residents.

To effectively combat the pest, the Miaoli DARES successfully selected the 'black egg wasp' as a natural predator of the rice black bug. They overcame bottlenecks in release techniques and established a mass-production system. With support from the Agriculture and Food Agency, they collaborated deeply with 'Tzu-Yuan Rice Mill,' a local organic rice producer in Guanshan, to combine local industrial strength and promote the field application of the black egg wasp, precisely suppressing pest density at the source.

Miaoli DARES observed that during the infestation, organic rice yields in the Guanshan area were 3.5 metric tons per hectare. Thanks to the research and application of the black egg wasp technology, yields have recovered to between 5.39 and 5.56 metric tons per hectare, demonstrating the excellent effectiveness of biological control using natural predators.

Miaoli DARES has already promoted the 'black egg wasp' to organic farming areas such as Chishang in Taitung and Fuli in Hualien, effectively reducing the risk of pest spread. Statistics show that from 2023 to 2025, the cumulative number of releases reached several million. Currently, only sporadic damage remains in the Guanshan area, and organic rice yields have returned to pre-outbreak levels.