Pathogenicity of a microsporidium isolate from the diamondback moth against noctuid moths: characterization and implications for microbiological pest management
Background: Due to problems with chemical control, there is increasing interest in the use of microsporidia for control of lepidopteran pests. However, there have been few studies to evaluate the susceptibility of exotic species to microsporidia from indigenous Lepidoptera. Methodology/Principal...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
The Public Library of Science (PLoS)
2013
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/45279/ http://irep.iium.edu.my/45279/ http://irep.iium.edu.my/45279/1/publication_1_plos_one_2013.pdf |
| Summary: | Background: Due to problems with chemical control, there is increasing interest in the use of microsporidia for control of
lepidopteran pests. However, there have been few studies to evaluate the susceptibility of exotic species to microsporidia
from indigenous Lepidoptera.
Methodology/Principal Findings: We investigated some biological characteristics of the microsporidian parasite isolated
from wild Plutella xylostella (PX) and evaluated its pathogenicity on the laboratory responses of sympatric invasive and
resident noctuid moths. There were significant differences in spore size and morphology between PX and Spodoptera litura
(SL) isolates. Spores of PX isolate were ovocylindrical, while those of SL were oval. PX spores were 1.05 times longer than
those of SL, which in turn were 1.49 times wider than those of the PX. The timing of infection peaks was much shorter in SL
and resulted in earlier larval death. There were no noticeable differences in amplicon size (two DNA fragments were each
about 1200 base pairs in length). Phylogenetic analysis revealed that the small subunit (SSU) rRNA gene sequences of the
two isolates shared a clade with Nosema/Vairimorpha sequences. The absence of octospores in infected spodopteran tissues
suggested that PX and SL spores are closely related to Nosema plutellae and N. bombycis, respectively. Both SL and S. exigua
(SE) exhibited susceptibility to the PX isolate infection, but showed different infection patterns. Tissular infection was more
diverse in the former and resulted in much greater spore production and larval mortality. Microsporidium-infected larvae
pupated among both infected and control larvae, but adult emergence occurred only in the second group.
Conclusion/Significance: The PX isolate infection prevented completion of development of most leafworm and beet
armyworm larvae. The ability of the microsporidian isolate to severely infect and kill larvae of both native and introduced
spodopterans makes it a valuable candidate for biocontrol against lepidopteran pests. |
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