The Biocidal capacity of Datura (Datura stramonium L.) leaves and flowers and Cannabis (Cannabis sativa L.) seeds on some Mosquito’s larvae (Diptera: Culicidae)

Abstract

Plant-based alternative pesticides are safe, effective, eco-friendly and can be used instead of synthetic pesticides. The aim of this study was to evaluate the biocidal capacity of Datura stramonium leaves (DL) and flowers (DF) and Cannabis sativa seeds (CS) on Anopheles arabiensis, Culex quiquefasciatus and Aedes aegypti larvae. The selected plant parts were collected from the experimental farm, the University garden. The LC50s of A. arabinoses larvae towards the ethanol extract of each plant part were taken to estimate the single diagnostic dose for the survival and deformities tests. GC-MS analysis for the selected plant parts was investigated. The results show that DL ethanol extract detected 14 compounds of which butanol,3-methyl is the main component (79.76%) followed by toluene (6.14%). Phytol was also detected (3.9%). 14 compounds were detected from DF of which formic acid,3-methylbut-2-yl ester was the main component (82.22%) followed by dodecanoic acid, ethyl ester (3.3%) and toluene (2.86%). Also, from CS, Dronabinol (41.4%) was the main component, followed by Cannabinol (10.38%), Phytol (10.38%) and Caryophylene (2.07%). The susceptibility test of An. arabiensis larvae revealed the LC50’s of 562.95 mg/L for DL, 424.41 mg/L for DF and 175.40 mg/L for CS. It was noticed that 3-6% of An. arabiensis and 1-28% of Culex quiquefasciatus and 12-22% of Aedes aegypti larvae developed to pupae and some of them developed to adult stage after one week. In the survival test, more than 70% of the larvae were killed by a concentration supposed to kill 50% or less of the larvae. Some deformations were monitored on Anopheles, Culex and Aedes larvae including swelled body, separated alimentary canal. Field assessment should be run and the concept of LC50 should be re-written.