Effects of Crude Extracts of Birbira (Millettia Ferruginea) Seed Powder in Solvents of Different Polarity Against Pea Aphid, Acyrthosiphon Pisum
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Date
2010-06
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Addis Ababa University
Abstract
This study was conducted in order to test for the contact toxicity and settling deterrence of
crude extracts of birbira, Millettia ferruginea, seeds powder in solvents of differenagainst pea aphid (A. pisum). It was evaluated as deionized water, acetic acid, acetone, chloroform, toluene and hexane extracts. Contact toxicity assay was carried out in the t polarity
whereas
ased on the
than the
e
than the
t mortality
. The contact
water to
ionized water,
d on the
observations.
settling
t although the
ct plants,
phids within three and four days time after treatments than the untreated control.
Nevertheless, the differences among the extracts were not significant. Still the more polar
solvents had the leading cumulative mortality records. Based on the results it can be concluded
that polar solvent extracts of birbira is powerful contact toxicant against A. pisum.
laboratory using these extracts at rates of 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 and 1.4 mg/mlsettling deterrence on excised leaves and contact toxicity on intact plants was bLC50 from the first assay. In ex-situ contact toxicity, all the extracts of birbira dissolved in
water caused significantly (p<0.05) higher mortality to the A. pisum in 5 hrs timeuntreated control. However, the pea aphids responded differently to the birbira extracts and thdeionized water extract was by far the most toxic that caused about 98.15% mortality followed
by the acetic acid extract (88.61%) which brought significantly more death chloroform, toluene and hexane extracts. Birbira extract in hexane caused the leasthan other extracts. The LC50 value was much lower for the deionized water extracted birbira
than the rest of the extracts but, it was the highest for hexane extracted birbiratoxic activity of birbira extracts decreased with decreasing polarity (from deionizedhexane) of the extracting solvents used. For each extract of birbira significantly higher
mortality was observed at the higher rates used. The LC50 birbira extracts of deacetic acid and hexane significantly (p<0.05) reduced the number of aphids settletreated leaves in the paired-choice settling deterrence activity assay, though these three
extracts did not show significant settling deterrence of aphids at all time of theSimilarly, some settling deterrence effects of the extracts were observed in no-choicedeterrence test. Significantly (p<0.05) fewer aphids settled only on acetone, chloroform and
toluene extracted birbira treated than the control leaves at 24 hrs after treatmendifferences among all the extracts were not significant. In the contact toxicity on intaall extracts except hexane extracted one caused significantly (p<0.05) higher mortality
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Biology