Abstract:
Objective As an important economic tree species, Litsea cubeba has been widely demonstrated and promoted in Liannan Yao Autonomous County, Guangdong Province. The occurrence of anthracnose has seriously affected the growth and survival of L. cubeba. Therefore, clarifying the occurrence degree of the disease and accurately identifying the type of pathogen can provide a scientific basis for the prevention and control of this disease.
Method Random field surveys and fixed monitoring were conducted in the demonstration planting area of the L. cubeba in Liannan Yao Autonomous County to records the changes in disease index from 2024 to 2025. Diseased parts of L. cubeba were collected, and pathogens were isolated by the tissue isolation method. The taxonomic status was determined based on the morphological and molecular biological characteristics of pathogens.
Result At present, the promoted L. cubeba varieties in Liannan Yao Autonomous County are L. cubeba var. cubeba and L. cubeba var. Formosana. Both varieties are susceptible to anthracnose, with the main affected parts being the leaves and branch forks. The disease trends to outbreak frequent during June to August, when rainfall is high. Four strains (LZSCZ01, LZSCZ10, LZSCZ04, LZSCZ14) were isolated from the stem of the diseased Litsea cubeba, six strains (SCZJS03, SCZJS05, SCZJS06, SCZQS03, SCZQS04, SCZQS07) were isolated from the leaves with the similar morphological characteristics.The sequencing results of 10 isolated strains were subjected to Blast comparison, which initially confirmed that LZSCZ01 belongs to Epicoccum, while the other 9 strains are all Colletotrichum sp. Further phylogenetic tree analysis based on multiple genes of the 9 Colletotrichum indicated that they are all C. fructicola. Four strains (LZSCZ01, LZSCZ04, LZSCZ10, LZSCZ14) were selected for re-inoculation experiments. The results showed that LZSCZ01 was non-pathogenic, while the Colletotrichum fructicola strains LZSCZ04, LZSCZ10 and LZSCZ14 were pathogenic and conformed to Koch's postulates.
Conclusion The anthracnose in L. cubeba in Liannan Yao Autonomous County is mainly caused byC. fructicola. Infection leaves and stems leads to leaves and stems wilting, and the occurrence of the disease is closely related to rainfall. This is the first report of this pathogen causing anthracnose in L. cubeba.