PESTICIDAL EFFECTS OF EXTRACTS FROM DIFFERENT PARTS OF NEEM PLANT {Azadirachta indica)
PESTICIDAL EFFECTS OF EXTRACTS FROM DIFFERENT PARTS OF NEEM PLANT {Azadirachta indica)
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Date
1998-03
Authors
SIKOD, RAYMOND DINGA
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Abstract
Various water dispersible powder (WDP) 5% concentration and
dust preparation (DP) 5% concentration both based on
crushed neem kernel and leaf, and an emulsifiable
concentrate (EC) based on neem kernel oil were prepared.
Their azadirachtin content were determined. These
formulations (WDP and EC) were evaluated on the field
against the two major pest of cowpea i.e. the leaf beetle
Ootheca mutabilis (Sahl) and the pod sucking bug
Clavigralla tomentosicollis (Stal) and in the laboratory
(DP) against Callosobrachus maculatus (Fab) an economically
important pest of stored cowpea grains. The various
formulations were compared with each other and with a
commercially available insecticide.
In the field evaluation, the various formulations not only
significantly (P < 0.05) reduced damage due to Ootheca
mutabilis and increase grain yield in cowpea, but also gave
a performance comparable to that of the synthetic
insecticide (Cypermethrin). None of the formulations gave
complete protection, but treatments with neem seed water
extract (NSWE) and neem cake water extract (NCWE) resulted
in less foliar damage and a lower incidence of Clavigralla
tomentosicollis than the other formulations. In most
instances, untreated plots were severely damaged whereas
those protected with various neem extracts were not
attacked or only slightly damaged. This was confirmed by
a strong and significant (P < 0.05) correlation between
azadirachtin and pesticidal effects (r = - 0.96, .86, -.97,
-0.6 and -0.6) for leaf damage, yield, insect population,
seed damage and weight loss respectively. However, there
were significant (P < 0.05) variations among the
treatments.
Laboratory trials for post-harvest storage indicated that,
grains treated with various neem dust preparation (DP) and
neem oil (4ml/kg) caused significant (P < 0.05) reduction
in number of progeny and survival rate of Callosobrachus
maculatus. There was no adult survivors or progeny
production in grains treated with neem oil. Neem oil and
neem cake protected the grains against feeding by
Callosobrachus maculatus resulting in lower percentage
weight loss and damage seeds compared to untreated grains
and the standard actellic dust 16 weeks after infestation.
The germinative percentage of seed treated with these
materials indicated that, they do not impair viability and
hence could be used in preserving grains as well as seeds
for planting.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA, IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF
SCIENCE (M.Sc) DEGREE IN BIOCHEMISTRY
DEPARTMENT OF BIOCHEMISTRY
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA.
Keywords
PESTICIDAL,, EFFECTS,, EXTRACTS,, DIFFERENT,, PARTS,, NEEM,, PLANT,, Azadirachta indica