Effects of aqueous and ethanolic leaves and flowerbuds extracts of Croton zambezicus on the larval growth of African lady bird Epilachna chrysomelina F. (Coleoptera : Chrysomelidae)‎

Abstract EN

The Croton zambezicus, Um-Ghalaila is a common name.

"Ghussga-yene" is a vernacular name used by a local community, where the plant parts were collected.

It classified as aramotic plant and may be active agent as natural product (plate:7 &8).

The plant leaves and flowerbuds were collected in South Kordofan State in January.The objectives of this study are: i .To determine the quantities and % of the extractable from leaves and flowerbuds of Croton zambezicus , ii.

To evaluate efficacy of bioactive compounds present in the plant as insecticide, against 3rd- larval (L3) stage of inect, Epilachna chrysomelina; using both aq.extr.

and EtOH-ex-tr .Electric shaker apparatus and Rotary vacuum evaporator for aqueous extracts and Soxhlet apparatus and rotary vacuum evaporator for ethanol (Et.OH) and hexane (hex)-extracts were used.

E.chrysomelina 3rdin&ars larvae (L3), average weight (30±2mg) were used.Three replicates were adopted .

Only one larva placed in each Petri-dish lined with a moi& filter paper, and treated or untreated leaf discs of a cucurbit were used as food source.

Concentrations of 1, 2.5 and 5% were used.

Control used in the bioassay was(.

Discs + extracting solvent+ 1 larva) .

The most important results obtained in all treatments investigated throughout this study showed that : All plant leaf and flowerbuds-aqueous extract and Ethanolic extract at all doses used were highly effec-tive in reducing insect parameters measured compared to those recorded in control.The larval food consumtion of leaf aqueous extract within 24hrs were5.7,6,o and7.3mg for the concentrations 5%.2.5% and 1% respectively .The control consumed 30.

0mg in the same period .

An average weight loss/larva fed on leaf aq- extr.were 10.1,14.1 and 4.2 at conc.

5%,2.5% and 1%,whereas control larvae gained 80mg body weight .The larval average food consumtion fed on flowerbuds aqueous extract at first and second 24hrs of test were 2.5and 10.0mg at conc.5% respectively ,and about 6.2and8.5 mg at2.5%, while 9.0 and 11.0mg at conc.

1% .The controls, were 30.0and 128.0mg for the same periods .

In the case of larval weight loss when fed on aqueous extrac of flower buds during 48hrs, larval recorded 3.2mg at conc.5% as weight loss and at 2.5% and 1% the larval gained, 2.1 and 5.6mg respectively .control weight loss was two times less than those recorded in the conc.5% .Regarding to the effect of ethanolic leaf extract on weight loss, the larval during the second 24hr of 48hrs loss weight of 5.3mg at conc.

5%,while at conc.2.5% and 1 %it gained 5.0 and 10.8 mg respectively.