Entomopathogenic nematodes and their potential for use against banana weevil {cosmopolites sordidus germar) in Tanzania.
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Date
2009
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Publisher
Sokoine University of Agriculture
Abstract
A survey on the occurrence of entomopathogenic nematodes (EPNs) was conducted
in selected banana fields in three regions (Coast, Mbeya and Morogoro) of Tanzania.
The main objective of the study was to isolate entomopathogenic nematodes naturally
occurring in banana fields in Tanzania and to test the effectiveness of these
nematodes against banana weevil (Cosmopolites sordidus Germar). The presence of
entomopathogenic nematodes
is reported for the first time
in Tanzania.
Entomopathogenic nematodes were found in soils sampled from banana fields in
Coast region of Tanzania using the Great wax moth, (Galleria mellonella L.) larvae
as bait. Four (4.4%) out of 90 samples contained nematodes from which nine isolates
of entomopathogenic nematodes were obtained. Seven isolates were identified as
Steinernema spp while two isolates were of Heterorhabdits spp. The nine isolates
were studied to determine their virulence against larvae and adults of C. Sordidus.
Nematode concentrations of 0.35, 3.5 and 7.0 infective juveniles cm'2 were used. All
isolates were able to invade C. sordidus larvae but adults were rarely infected. At
concentrations of 3.5 and 7.0 cm'
MK7A (Steinernema spp) and MK7B
(Heterorhabdits spp) caused the highest larval mortality of up to 100%. The average
larval mortality ranged between 52% - 78.67% with isolates MK7C and MK7B
(Heterorhabdits spp) being the most virulent causing an average larval mortality of
77.33% and 78.67% respectively. The potential of using EPNs as a biocontrol agent
for C. sordidus larvae based on laboratory results has been demonstrated. However
performance of these isolates under field condition must be evaluated and tested.
Proper delivery systems for use in different banana production systems need to be
developed and tested.
Description
The Norwegian Institute for Agricultural and Environmental Research (BIOFORSK),
Keywords
Entomopathogenic nematodes, Banana weevil, Three regions Regions (Coast, Mbeya, Morogoro), Tanzania, banana fields