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Distribution and damage characteristics of an emerging
insect pest of cashew, Plocaederus ferrugineus L. (Coleoptera:
Cerambycidae) In Nigeria: A preliminary report
E.U. Asogwa*, J.C.
Anikwe, T.C.N. Ndubuaku and F.A. Okelana
Cashew Research Programme,
Cocoa Research Institute of Nigeria,
Ibadan,
Nigeria.
*Corresponding author.
E-mail:
ucheasogwa1@yahoo.com.
Accepted 17 November, 2008 |
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Among the numerous insect
pests infesting cashew in Nigeria, the cashew trunk and root
borer, Plocaederus ferrugineus L. (Coleoptera:
Cerambycidae) is fast becoming the most dreaded because its
infestation results in the sudden death of the tree within
weeks. Observations at Ochaja in 1999/2000 and at Ibadan in
2005 of “sudden death” of mature cashew trees within few
weeks of infestation were indications of emergence of new
pest of cashew in Nigeria, which needs urgent investigation.
Frass and gum exudates were collected from the trunk base of
dead plants before they were cut down and exhumed carefully
from the soil. Soil samples were collected from beneath the
excavated roots. The bored holes on the trunk and roots were
excised to ex-pose their frass and
gum contents. Both the frass and gum exudates collected
from the base of the cashew trunk and those from excised
trunk and roots together with the soil samples from beneath
the excavated roots were thinly spread out in the laboratory
to search for the various life stages of the beetles. Brief
description of the beetle’s life stages and parts of the
infested/dead stands were made. The rate of infestation of
cashew trees at Ibadan was 18.13%, resulting in a death rate
of 1.88% of trees, while the infestation
rate at Ochaja was 13.3% with a death rate of 6.38%. The
eggs were conspicuously absent at the time of this
assessment as they had all emerged and developed into
larvae, pupae and adults. The control of the pest at
advanced stage of the larval development was very difficult;
hence control measures were recommended
to be initiated at early stage of infestation. Strict
cultural practices gave desired results.
Key words:
Infestation, beetles, borer, frass, exudates, larvae, pupae,
adults. |
