Evaluating trichocompost for disease control and yield improvement in potatoes under tropical dryland conditions in South Central Timor, Indonesia

Abstract. Simamora AV, Serangmo DYL, Londingkene JA, Nahas AE, Nenotek PS, Hahuly MV, Kasim M, Mahayasa INW, Gandut YRY, Widinugraheni S, Hosang EY. 2025. Evaluating trichocompost for disease control and yield improvement in potatoes under tropical dryland conditions in South Central Timor, Indonesia. Intl J Trop Drylands 9: 159-168. Potato (Solanum tuberosum) is a key horticultural crop in Indonesia. In tropical dryland areas such as South-Central Timor, Indonesia, potato cultivation faces challenges including limited rainfall, poor soil fertility, and high disease pressure. Late blight caused by Phytophthora infestans remains one of the most destructive diseases. This study evaluated the biocontrol efficacy of Trichoderma harzianum formulated as trichocompost for disease suppression and yield improvement under dryland conditions. Unlike many previous studies that focused on in vitro or greenhouse testing, this research prioritized native Trichoderma isolates adapted to potato rhizosphere soil and validated their performance under harsh Entisol-based dryland field conditions. Five isolates were obtained from the rhizosphere of healthy potato plants and characterized morphologically. Their antagonistic activity against P. infestans was assessed using the dual culture method. All isolates inhibited P. infestans by more than 70%, with Trichoderma 04 showing the highest inhibition. Molecular identification confirmed this isolate as T. harzianum, which was selected for field evaluation in four treatments: control, trichocompost applied two weeks before planting (T1), at planting (T2), and two weeks after planting (T3). Data from the dual culture assay and field experiment were analyzed using ANOVA and followed by DMRT at p