First record of Fusarium verticillioides causing sorghum wilt in south Sulawesi Indonesia: field incidence, severity, and molecular confirmation

Abstract

Abstract Sorghum (Sorghum bicolor (L.) Moench) is an important crop for food diversification and bioenergy programs in Indonesia due to its drought tolerance, adaptability to marginal lands, and high nutritional value. However, a previously unreported sorghum wilt disease in Indonesia is hindering its productivity. Morphological, molecular, and pathogenicity testing methods were used in this study to identify the cause of sorghum wilt in South Sulawesi. According to a field survey conducted in Maros Regency (2025), disease incidence ranged from 11 percent to 100 percent, and disease severity increased as the plants aged. The Super 1 variety showed a 27.72% incidence 21 days after planting (DAP), while Numbu showed 11.08%. At 56 days after planting (DAP), both varieties reached 100% incidence with severity reaching 91.7%. Pathogen isolation produced colonies with long-chained microconidia ranging in color from white to pale purple. Macroconidia are rarely septate (3–5), and no chlamydospores are present. Isolate FV-SR01 belongs to the Fusarium verticillioides clade, showing 99.8–100% similarity to reference strains, according to molecular analysis based on ITS and TEF1-α sequences. According to pathogenicity tests, seedlings exhibited wilting symptoms within ten to twelve days after inoculation; the disease severity index reached 3.6 (80–90% wilting), and the same isolate was successfully re-isolated, fulfilling Koch’s postulates. This study indicates that F. verticillioides is the primary cause of wilt disease in sorghum in South Sulawesi. This report is the first of its kind in Indonesia and will help strengthen the plant disease database and aid in the development of sustainable sorghum management strategies.