Screening on bast fiber plants resistant to spiral stem borer, Agrilus acutus (Coleoptera: Buprestidae)

Bast fiber plants, such as kenaf, jute, roselle, and their relatives, produce natural fibers as raw materials for various strategic industries and contribute to environmental preservation. The spiral stem borer (SSB), Agrilus acutus, infests stem of bast fiber plants and potentially reduces fiber production and quality. The symptom of its infestation shows a presence of an elongated gall on the stem which causes the stem broken. This study aimed to evaluate SSB (A. acutus) preference of 70 accessions of bast fiber plant species, namely jute (Corchorus olitorius L. and C. capsularis L.), kenaf (Hibiscus cannabinus L.), and roselle (H. sabdariffa L. and H. radiatus Willd.). This information could be useful for selection of parents in plant breeding program for developing resistant varieties with non-preference mechanisms of SSB infestation. This study used 18 jute accessions, 33 kenaf accessions, and 19 roselle accessions. Stem morphology characters (color, surface, middle diameter, and top diameter) were used as parameters for SSB preference were correlated with the gall symptoms caused by SSB infestation. The results showed that the gall symptoms due to SSB infestation were only found in kenaf accessions. The gall symptoms were mostly found in the middle part of kenaf stem with a median proportion of infestation of 42% in the range of 25–87%. The highest preference of SSB was on the character of green and spiky stems, i.e. 33 accessions of kenaf. Accessions PI 270108 and PI 329183 were observed as accessions with the lowest (20%) and the highest (91%) indication of SSB infestation, respectively.