Abstract:
The effects of methanolic extracts from &?ornoen s f o l ~ n ~ raan ,a quatic macr%hyte, on life
cycle stages of both laboratory-read and freldcollccted hedes mmqui~oes were studied. Twenty (20)
Is' and 4Ih instar lame of the Aedcs niosquitoes were eapscd to different dilutions of the plant exlract
for 24 hours at room temperature using Macbdo, 1997,method and the lethality effects at each
concentration TcveT calculated and recorded. The inhibitory eflkcts of the platit extract on the life cycle
slages of the A d a mosquitoes were also checked, using Sivagnaname, 2004, method, until all thc
pupal stages emanating from thc surviving larval forms fuNy transformed to adult. Phytochemical
analyses of the extract showed that some of its constituents were either lethal or had inhibitory effects
on OW or other fonns of the life cycle stages of the test mosquitoes. lieSu1t~ obtained showed that at
concciltrations of 5 . 0 0 r n g / r n l , 2 . ~ ~ ~ m1.0l ,0 mgh1, 0.50n\dml, 0.10rnglm1, O.OSn~glrn!o f the extract.
and ~ . 0 4 m l ~orfn t~he DMSO control. the mean Icttlality ratcs Tor the laboratory-reared I" iinstar Tarvae
of the Ades niosquitoes were 20 (100%*0), 20 (l00%*0), 18 (90%i2.89), 9.66 {48.33%*6.0 I), 7
(35%*7.64), O (0%+0.00).O (0%*0.00) while that of the 4Ih ins~arla rvae were 19.33 (96.67%*1.67).
16.33 (81.6?d/&.41$, 11.66 (58.33%*3.33), 3.33 (l6.676/a*4.4 I), 2.33 (1 1.67%*4.41), 0
(0.00'W0.00), 0 j0.006/&0.00) respcctiveIy. The correspondillg values for the 15' instar larvae of the
field-coIleckd Aedes mosquitoes were 18.66 (73.33YdI .67), 16.66 (83.330/&3.33), 1 I .66
(58.33%*7.27), 2.33 ( I !.67%f 4.4 I), 2.66 (1 3,33%f 1.67). 0 (U.00%f0.00) whiIe that OF lhe 4' instar
larve were 16.66 (83.33%.+7.26), 10 (50.000/&2.87), 4.66 (23.33Y0f4.41)~ 0 (O,OO%fl.UO}. 0
(r>.OO%*O.QO), 0 ~O.O~/~O.OO)0, (0.00?/&.00) respectively at the graded concentrations. The effeets
o.f graded concentrations of the cxtract on cunlulative number and percentage of tra~isfomationn s well
as effocr of the graded concentrations: on the time it took to coinpletc the Life cycle were also studied
using Sivagnanamnc, 2004, method. The study showed that cumulative transformation rates were more
at lower concentrations than rhar at higher concentrations. The study aka showed that it took Ionger
time (days) for the life cycle to be complctcd at higher coneenlrations than at Iower concentrations. The
eflect oF gracled concentrations of the extract on ;Both the labratoy-reared and fdd-collected
tnosquitoes when compared were found ilo be significant at !PA, S%, and 1% levels respectively.
