INTERACTION EFFECT OF FLACHERIE BACTERIAL ISOLATES ASSOCIATED WITH BmCPV OF SILKWORM (Bombyx mori L.)
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Date
2019-12-26
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UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
The studies on “Interaction effect of flacherie bacterial isolates associated
with BmCPV of silkworm (Bombyx mori L.)” revealed that, out of forty different
bacterial isolates screened from the BmCPV (C) infected midgut of silkworm, fourteen
isolates were molecular characterized and identified by using 16S rRNA gene sequencing
as Klebsiella aerogenes, Acinetobacter baumannii, Providencia rettgeri, Proteus
vulgaris, Bacillus pumilus, Paenibacillus durus, Salmonella bongori, Bacillus
licheniformis, Serratia marcescens, Exiguobacterium aurantiacum and Bacillus subtilis.
Among the three bacterial isolates viz., Acinetobacter baumannii (A), Bacillus pumilus
(Bp) and Bacillus licheniformis (Bl) were selected for in-vivo studies. Oral inoculation of
above to III, IV and V instar recorded extended moulting and larval duration. In addition,
maximum ET50 for symptoms expression and mortality (days) were recorded (14.24 and
23.57) in III instar batch followed by IV (10.23 & 14.12) whereas, minimum of 8.33 and
10.24 recorded in V instar (C+A). In triple inoculation viz., C+A+Bp (25.33, 76.67 and
23.33 %), C+Bp+Bl (23.33, 82.67 and 17.33 %) and C+Bl+A (26.67, 78.00 and 22.00 %)
were recorded for per cent worms entering spinning, ERR and larval mortality
respectively in fifth instar batch. The C+A+Bp+Bl recorded minimum cocoon weight
(0.85, 0.00 & 0.90 g), shell weight (0.06, 0.00 & 0.07 g) and shell percentage (7.40, 0.00
& 7.77 %) in all the three instars whereas, maximum was recorded in C+A compared to
control. It was clearly inferred that, IV instar batch found to be highly sensitive to
BmCPV and bacterial infections, followed by V and III instar inoculated batches.