DFNet

May 20, 2026 | Taipei Times |

The Tainan District Agricultural Research and Extension Station has urged pomelo growers to strengthen monitoring and preventive measures against long-horned beetles and citrus rust mites as Taiwan enters the plum rain season. High humidity and frequent rainfall create favorable conditions for pests and diseases, including fungal infections such as anthracnose and fruit rot, as well as bacterial diseases.

Long-horned beetles are a major concern from June to mid-July. Their larvae feed on citrus roots, disrupting water and nutrient uptake, which can cause yellowing leaves, premature fruit ripening, yield losses, and even tree death. Growers are advised to improve orchard sanitation, remove fallen debris, and use traps such as wooden boards or rolled newspapers to capture eggs before they hatch.

The station also warned of increased risk of citrus rust mites, which damage pomelo peels by feeding on fruit surfaces and causing brown or black discoloration known as “blackened” pomeloes. Warmer temperatures and sunnier conditions this year may increase infestations. In addition to pesticide use, growers are encouraged to prune trees to improve airflow and sunlight penetration, helping reduce mite populations and protect fruit quality.

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