الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 139 |  |  |
| | | from | 139 | | |
Abstract
The objective of this study was to evaluate the toxic effects of two
plant extracts , namely acetone and petroleum ether extracts of Lantana
camara and Nerium oleander alone and in mixtures with the LCso of
pirimiphos methyl and lor fenvalerate (sumicidin), on mortality and
reduction in F1 progeny of the rice weevil (Sitophilus oryzae L.) and the
red flour beetle (Tribolium castaneum Herbst). Besides, the repellency
effects of the two plant extracts against the two insect species were
investigated.
Experiments were performed at the stored product pests laboratory
of the plant protection Department, Faculty of Agriculture, Moshtohor,
Zagazig University.
The obtained results could be summarized as follows :-
1- Toxicity and effect of plant acetone extracts:
Results of S. oryzae showed that very low adult mortality values
were observed after 2 days from the treatment. Mortality increased with
increasing concentration and exposure period. After 21 days from the
treatment, mortality percentages ranged from 13.2-44.2% and 27.8-100%
at the various concentrations (1,2,4,8 and 16%) of Lantana Camara and
Nerium oleander acetone extract, respectively.
Reduction in Fl progeny was between 19.4 - 63.2% and 75.3 -
93.9% for the two plant extracts, respectively.
Nerium oleander acetone extract was more toxic against the adults
of S. oryzae than the acetone extract of Lantana Camara.
._-- _.._--- .
-103-
Results of T. castaneum revealed very low mortality values at all
concentrations of the two plant extracts even after 21 days from the
treatment.
Reduction in F1 progeny was obviously higher than mortalily at
various concentrations.
Results indicated clearly that the acetone extracts of the two plants
were more effective against the adults of the two insect species under
study . The bio-activity of Lantana Camara acetone extract was slightly
greater against T.castaneum than Nerium oleander acetone extract.
2- Toxicity and effect of petroleum ether extracts:
Data revealed that petroleum ether extracts of the two plants was
more effective against Sioryzae and T.castaneum than the acetone
extracts.
Also, petroleum ether extract of Nerium oleander was less effective
against T.castaneum than Lantana camara.
Reduction in F1 progeny was much higher than mortalities at all
tested concentrations with S.oryzae and only at higher concentrations in
case of T.castaneum.
3- Repellency effect of the two plant extracts :
3.1- acetone extracts :-
Repellency results fbr S.oryzae adults showed that , at all tested
concentrations, average repellency of Lantana Camara extract was slightly
greater than control during the observation period of 21 days .
- -_.- _._-_. - --~----
-104-
Nerium oleander acetone extract exhibited only at 8 and 16 %
concentrations slightly higher repellency values than control.
In case of T castaneum adults, no significant differences were
found between the average repellency of Lantana camara acetone extract
and the control at all tested concentrations. But Nerium oleander acetone
extract produced relatively higher repellency values at all concentrations
than control.
3.2- Petroleum ether extracts :-
Average repellency values of Lantana Camara petroleum ether
extract with Sioryzae adults were significantly greater at the higher
concentrations of 8 and 16 % only, than control.
Similar result was achieved with the petroleum ether extract of
Nerium oleander for the adults of S.oryzae.
Repellency results for T’castaneum adults indicated that petroleum
ether extract of Nerium oleander did not show clearly repellency effects at
all tested concentrations in comparison with control. But, in case of
Lantana camara petroleum ether extract, slight to moderate repellency
values were achieved at various concentrations.
4- Joint action of minores:
4.1- Joint action of the .inures of plant acetone extract plus LCso of
pirimiphos methyl :-
Results of joint action oftbe various mixtures were expressed numerically
as co-toxicity factor values after 7 days from the initial treatment.
---- - - --~--
~105-
Results of pirimiphos methyl plus plant acetone extract mixtures
showed a pronounced antagonism with S. oryzae, and potentiating action
with Ticastaneum at all tested concentrations ,of Lantana Camara and
Nerium oleander extracts.
4.2- Joint action of the mixtures of petroleum ether extract of the
plant plus LCso of pirimiphos methyl:
Results of co-toxicity factor value’s for S.oryzae indicated that
mixtures of pirimiphos methyl plus petroleum ether extract of Lantana
Camara produced additive effects at all concentrations. Combinations of
Nerium oleander petroleum ether extracts plus the same insecticide
resulted in a pronounced antagonism.
Results of co-toxicity factor values for T. castaneum indicated an
additive effect at 8 and 16% concentrations, and a pronounced antagonism
at 1,2 and 4% concentrations of Lantana camara petroleum ether extracts
plus pirimiphos methyl.
Mixtures of Nerium oleander extracts plus the insecticide produced
additive effect at all concentrations with exception of the mixture at 1%
which resulted in an antagonistic effect.
4.3- Joint action of mixtures of plant acetone extract plus Ley of
fenvalerate (sumicidin) :-
Results of co-toxicity factor values for Ssoryzae showed that all
fenvalerate acetone plant extract mixtures resulted in a pronounced
antagonism.
Results of T. castaneum indicated also that all fenvalerate plus plant
extract mixtures of the two plants resulted in a pronounced antagonism.
- - ,--- ._--- .- --._. -- --.- _. -
-106-
4.4- Joint action of mixtures of petroleum ether extracts of the plants
plus LCso of fenvalerate (sumicidin) :-
Results of co-toxicity factor values with Sioryzae indicated clearly
that all fenvalerate plus Nerium oleander extract combinations resulted in
a pronounced antagonism.
Mixtures of fenvalerate plus Lantana Camara extracts produced an
additive effect at 8 and 16% concentrations and an antagonistic effect at
the other concentratios (1,2 and 4%) .
Results for T.castaneum indicated antoganistic effects at all
concentrations of petroleum ether extracts of the two plants plus
fenvalerate.