Study on Ovicidal, Larval Settlement, Feeding and Oviposition Deterrence Effects of Seed Kernel Powder Extracts of Birbira, (Milletia ferruginea) on Diamondback moth, (Plutella. xylostella L.) (Lepidoptera: Plutellidae)
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Date
2002-06
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Addis Ababa University
Abstract
Solvent extractions having different polarities with different doses prepared from birbira
tree seeds, Milletia ferruginea (Hochst) Baker. This study was carried out to assay the ovicidal, larval
settlement, feeding and oviposition deterrence effects on Diamondback moth (Plutella xylostella L.).
Leaf dipping method was used to run both assays by using the extracts from birbira seed kernel
powder in water (w/v): 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, and 1.4 mg/ml. In the assays significantly higher
larval mortality was recorded on leaves treated with polar than the non polar and Chloroform extracts.
Days to the 1st larval mortality was observed within a day after the exposure of the 3rd instar larvae on
treated leaves with different solvent extracts of birbira except the Water. Days to the last mortality
were observed on the 14th days on all extracts. Days to the highest larval mortality were significantly
higher for Water, Acetic acid and Acetone, extracts at 0.8, 0.6 and 0.4 mg/ml; respectively for the
other extracts it was significantly higher at the higher rates of application. In the control most larvae
pupated on 8th day. Acetone prevented pupation at the higher rates, Water, Acetic acid, Chloroform
and Hexane allowed fewer larvae to pupate, and in contrast more number of larvae was pupated in
Toluene extract at all the rates. Significantly small numbers of adults were emerged at the higher rates
of Water, Acetic acid and Acetone than the others. Adults took longer time to emerge from pupae on
Chloroform, Toluene and Hexane extracts at the higher rates. Eggs unhatchability was higher at 0.4
mg/ml and increased at the rate of 1.4 mg/ml for polar extracts. However, significant eggs
unhatchability was recorded only at the higher rates for the non polar extracts. Oviposition deterrence
was significantly lower at the lower rates of Water, Acetic acid and Acetone full deterrence was
recorded at the higher rates, in contrast Toluene and Hexane showed least deterrence effect even at the
higher rates of application. The number of eggs oviposited in the inner surface of the Petri dishes
were higher at all the rates except for Water, Acetone and Chloroform extracts. Numbers of eggs
deposited in the inner walls of the cages were higher at 0.6 and 1.4 mg/ml for Water and at 0.4 and 1.4
mg/ml for Hexane. Small numbers of larvae were settled on non polar solvent extracts. Mortality
caused by extracts with Water, and Acetone was very high, and have much smaller LC50 values. In
contrast the LC50 was higher for the other extracts and caused significant larvae kill only at the higher
rates. Thus, results of this study indicate that M. ferrugginea has a good possibility for controlling P.
xylostella (L.).
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Biology