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Bioassay Evaluation of the Entomopathogenic Fungi, Beauveria bassaina Vuellemin Against Eggs and Nymphs of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) |
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Mohammad A. Al-Deghairi |
Abstract:
This study was carried out to determine the lethal effect
of the entomopathogenic fungi, Beauveria bassaina Vuell. on eggs,
young and old nymphs of the whitefly, Bemisia tabaci Genn. Mortality
percentage was significantly differed based on stage of B. tabaci
and conidial concentrations of B. bassina. Average of the infection
level to insect was very low particularly in eggs with only 4.49%, even
with higher conidial concentrations (6x106 conidia mL–1).
Whereas, it was higher with 1st and 2nd instars (42.045%) and 3rd and
4th instars (35.93%). Three parameters was assessed with B. tabaci
eggs, namely; egg infection, egg hatchability and crawlers emergence.
Egg mortality percentages averaged 1.2, 4.27 and 8.0% with fungal concentration
2x106, 4x106 and 6x106 conidia mL–1,
respectively. Daily infection percentages were varied depend upon the
conidial concentration where the highest infection rate of eggs was occurred
with 6x106, followed by 4x106 conidia mL–1.
Egg hatch was very high, while the mortality among the emerged crawlers
was neglectable compared with the check. Efficiency of B. bassaina
on whitefly nymphs also was varied based on the insect instar and
fungal concentration. Mortality percentages were obviously higher to young
nymphs (1st and 2nd instars) than to older ones (3rd and 4th instars).
The results indicated that nymphs were highly susceptible to fungal treatment
compared with eggs. Additionally, pathogenicity and virulence of B.
bassaina against B. tabaci immatures was not indicated by LC50
only, but also, by the time in days (LT50) required to achieve
50% mortality of an insect.
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How to cite this article:
Mohammad A. Al-Deghairi , 2008. Bioassay Evaluation of the Entomopathogenic Fungi, Beauveria bassaina Vuellemin Against Eggs and Nymphs of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae). Pakistan Journal of Biological Sciences, 11: 1551-1560.
DOI: 10.3923/pjbs.2008.1551.1560
URL: https://scialert.net/abstract/?doi=pjbs.2008.1551.1560
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