Antifeedant and toxic activity of Adhatoda vasica leaf extract against Spodoptera littoralis (Lep., Noctuidae)

Abstract

The effect of crude methanolic extracts of Adhatoda vasica leaves on the feeding and performance of Spodoptera littoralis larvae was investigated in the laboratory. Feeding on fresh leaves resulted in 100% mortality of larvae after 26 days of unsubstantial growth. The extract exhibited strong antifeedant and toxic activity against the larvae when applied either on leaf discs or incorporated into artificial diet. Under choice conditions the antifeedant index calculated over 72 h for neonate larvae increased significantly (from 71.5 ± 3.2 to 92.1 ± 4.2) as the concentration of extract in the treated diet increased from 200 to 1000 ppm. Consumption by the sixth instar larvae of leaf discs dipped in 0.01, 0.1 and 0.2% extract solutions was significantly lower than consumption of control discs in both choice and no‐choice tests. The latter two concentrations deterred feeding by 63.4 and 90.4%, respectively, under choice conditions, while only the 0.2% extract solution deterred feeding by 56.8% in the no‐choice test. Toxicity of the extracts was manifested by a high mortality, reduced growth rates, and low weight gain by larvae fed on diets containing 200–2000 ppm of the extract. No larvae survived to pupation under the latter concentration. The time to pupation increased from 15.8 ± 0.4 to 37.9 ± 4.1 days as the extract concentration in diet increased from 0 to 1000 ppm. When fed to the fifth instar larvae, the crude extract significantly reduced consumption, growth, utilization of ingested and digested food, and approximate digestibility. The consumption‐dependent growth efficiency of animals fed on extract‐free diet was significantly higher than the growth efficiency of animals fed on extract‐containing diets, suggesting both antifeedant and toxic activities of the extract.

Effect of Artemisia Annua L. On Deterrence and Nutritional Efficiency Of Lesser Mulberry Pyralid (Glyphodes Pylolais Walker) (lepidoptera: Pyralidae)

“…Deterrence index in the highest concentration reaches 90.2% and in the lowest concentration it is 61.13%. In higher concentrations, the larvae leaving treated food may be due to a rapid deterrence evoked by chemical sensila on mouth parts or retracted pulses coming from stomodael nervous system after ingestion (Sadek 2003) or toxic effects after ingestion. Liao and Chiu (1986) reported that toosendanin is not toxic for Mythimna separata but acts as a strong feeding deterrent.…”

Bioactivity of a water extract of boldus (Peumus boldus Molina) against Spodoptera frugiperda (J.E. Smith) and Helicoverpa zea Boddie (Lepidoptera: Noctuidae)

“…Each treatment had 20 replicates and the experiment was repeated five times on different days. The weight results were used to calculate the feeding dissuasion index (FDI; Sadek, 2003): FDI = ((Ic -It)/(Ic + It)) × 100 and the feeding inhibition index (FII; Raffa and Frazier, 1988): FII = ((Ic -It)/Ic)) × 100, where Ic = Ingestion of untreated diet, and It = ingestion of treated diet.…”

Evaluation of Plant Extracts on Mortality and Tunneling Activities of Subterranean Termites in Pakistan

“…One hundred gram (100 g) of powder from each of the plants was extracted in 200 ml of 80% methanol in the ratio of 1:2 (w/v) by following method of extraction (Sadek, 2003). It was kept for 72 hours at room temperature and shaken at intervals to get a better extraction.…”