First report of entomopathogenic nematodes from Tanzania and their virulence against larvae and adults of the banana weevil Cosmopolites sordidus (Coleoptera: Curculionidae)
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Date
2011-08-25
Journal Title
Journal ISSN
Volume Title
Publisher
International Journal of Tropical Insect Science
Abstract
A survey on the occurrence of entomopathogenic nematodes (EPNs) was
conducted in selected banana fields from three regions in Tanzania, namely Mbeya
(Southern Highlands), Morogoro (Lowland) and Pwani (Coast). The main objective of this
study was to isolate EPNs naturally occurring in banana fields in Tanzania and to test their
effect on banana weevil (Cosmopolites sordidus Germar 1824).We report for the first time the
presence of EPNs in Tanzania where four (4.4%) out of 90 samples contained nematodes in
the genera Steinernema and Heterorhabditis. EPNs were only isolated in the coastal region in
soils with a high sand content. The virulence of nine EPN isolates was tested against larvae
and adults of C. sordidus. All isolates caused mortality of the larval stages, whereas the
adults appeared resistant to nematode infection. Larval mortality was found to increase
significantly with increasing nematode dose. It was also shown that nematodes were able
to penetrate and establish in the banana weevil larvae in increasing numbers with
increasing nematode dose. The study indicates the potential for including EPNs in
management strategies of banana weevil.
Description
International Journal of Tropical Insect Science Vol. 31, No. 3, pp. 154–161, 2011 doi:10.1017/S1742758411000294
@ icipe 2011
Keywords
Banana weevil, Biological control, Cosmopolites sordidus, Entomopathogenic nematodes