Oviposition, Ovicidal and Feeding Responses of Potato Tuber Moth, Phthorimaea Operculella (Zeller) (Lepidoptera: Gelechiidae) to Birbira, Millettia Ferruginea (Hochst) Baker (Legumionosae: Papilionideae) Seed Powder Extracts.
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Date
2010-06
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Addis Ababa University
Abstract
The use of native plant species, Millettia ferruginea (Hochst) Baker known locally as
birbira, its deterrent/toxicity was assayed in relation to oviposition, ovicidal and
feeding (larval settlement) responses of PTM. M. ferruginea seed powder extracts
obtained using solvents of varying polarities (water, acetic acid, acetone, chloroform,
toluene and hexane) at eight serial diluents (w/v: 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 and
1.4mg birbira seed powder/ml of water) were prepared. The PTM eggs for ovicidal and
the host plant parts: potato tubers for oviposition, larvae feeding and adult emergence,
leaves for oviposition and neonate larvae settlement (settled, deterred and died)
responses were treated with seed powder extracts of birbira at each rate of
application. From the five replicates, observation were taken on the number of eggs
laid, active and terminated galleries, settled, deterred and died neonate larvae,
emerged healthy and deformed adults and number of eggs hatched and unhatched.
Finally, the mean number of eggs laid on treated and away treated substrates, active
and terminated galleries, mean number of successfully settled, rejected and died
neonate larvae and % of egg hatchability was analyzed. The LC50 values of birbira
seed powder extracts for PTM eggs and neonates were also determined, too. Results
revealed that the number of eggs laid on tubers and leaves, the number of active and
terminated galleries carved by PTM larvae, percentage of unhatched eggs, were
inversely proportional to the increase in rates of the extracts, whereas the number of
eggs laid on cages and chambers inner surfaces increase with the increase in the rate
of application of the extracts. Adult emergence did not show clear pattern as was the
case for most of the cases with the larvae and extracts has no impact in deformity of
adult except in acetic acid and chloroform. All birbira seed powder extracts applied on
host plant leaf inhibit settling of PTM neonate larvae and its lethal effect to neonates
increase with increased rates of application and hours of exposure. The results in this
study confirmed that M. ferruginea is a potential natural insecticide of many insect
pests.
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Biology