Antifeedant activity and disruptive effects of novel chitin synthesis inhibitors on the food metabolism of last instar larvae of Spodoptera littoralis Boisd. (Noctuidae: Lepidoptera)
Year: 2017
Type: article
Abstract: The present study was conducted to investigate the antifeedant activity of three novel chitin synthesis inhibitors (CSIs), viz. Novaluron (Nova.), Cyromazine (Cyro.) and Diofenolan (Dio.), and their disruptive effects on the different nutritional parameters of the destructive phytophagous pest Spodoptera littoralis. Fresh clean castor bean leaves were treated with LC50 of each CSI and offered to the early last instar larvae for 24 hrs or 72 hrs. All CSIs exhibited considerably antifeedant activities against larvae. Higher activity was exhibited after longer feeding period. Nova. exhibited the strongest antifeedant activity followed by Dio. and Cyro.. The food consumption was remarkably reduced, regardless the CSI and the feeding period. The strongest reducing effect was exhibited by Nova. followed by Dio. and Cyro.. Treated larvae achieved significantly inhibited approximate digestibility. Nova. exhibited the most potent effect followed by Dio. and Cyro.. The efficiency of conversion of ingested food into biomass (ECI) of larvae was severely inhibited by the tested CSIs. After feeding for 72 hrs, an exceptional case was observed since Nova. Enhanced ECI of larvae. The efficiency of conversion of digested food into biomass (ECD) was considerably enhanced after feeding on treated leaves for 24 hrs. In contrast, feeding of larvae for 72 hrs resulted in serious reduction of ECD. Also, the assimilation rate, relative metabolic rate, relative weight gain and growth rate were significantly regressed by all CSIs. The most suppressing action was exerted by Nova.. On the other hand, frass output was enhanced by all CSIs whatever the feeding period on treated leaves. Nova. was the most powerful CSI to promote larvae for frass production.
Author: Hamadah Sh.
Institution: Al-Azhar University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W2992745634