DEGENERATION OF ENTOMOGENOUS FUNGI

摘要: Fungi are notorious for losing virulence and changing their morphology when successively subcultured on artificial media. Various terms have been used to describe this phenomenon including phenotypic degeneration, instability, deterioration, dual phenomenon, saltation attenuation (Butt, 2002; Kawakami, 1960; Nagaich, 1973; Ibrahim et al., Ryan 2001). Morphological changes include a change in colour, growth form as well reduced sporulation. In article, the term degenerate is cover both of degeneration. Degenerate cultures major concern manufacturers fungal biocontrol agents (BCAs) since batches that inconsistent spore yield or will make product commercially unviable. Growers naturally would be reluctant use any product, which was potentially unstable. reported wide range insect-pathogenic fungi (Table 1). However, very little known about why degenerate. What clear strains differ stability maintained media with some clearly degenerating more rapidly than others irrespective whether parent culture derived from single multi-spore colony. Examination isolates unstable reveals these generally produce variants stable unpublished observations). The pattern degeneration also varies between isolates; sectors while decline production and/or virulence. This chapter examine two attributes cultures: briefly review factors could explain phenomena. Since widely human plant pathogenic fungi, comparisons made organisms.