Insecticidal potency of Aspergillus terreus against larvae and pupae of three mosquito species Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti

• Published in: Environmental science and pollution research international 2015-11, Vol.22 (21), p.17224-17237
• Main Authors: Ragavendran, Chinnasamy, Natarajan, Devarajan
• Format: Article
• Language: English
• Subjects: Acetic acid; Acids; Aedes - growth & development; Aedes aegypti; Animals; Anopheles - growth & development; Anopheles stephensi; Aquatic insects; Aquatic Pollution; Aspergillus - chemistry; Aspergillus terreus; Atmospheric Protection/Air Quality Control/Air Pollution; Carboxylic acids; Culex - growth & development; Culex quinquefasciatus; Dengue fever; Developmental stages; Dose-Response Relationship, Drug; Earth and Environmental Science; Ecotoxicology; Encephalitis; Environment; Environmental Chemistry; Environmental Health; Environmental science; Ethyl acetate; Fungi; Insecticides; Insecticides - isolation & purification; Laboratories; Larva - drug effects; Larvae; Larvicides; Lethal Dose 50; Liquid chromatography; Malaria; Methanol - chemistry; Molecular weight; Morphology; Mortality; Mosquitoes; Mycelia; Palmitic acid; Pest control; Public health; Pupa - drug effects; Research Article; Retention time; Studies; Time Factors; Toxicity; Toxicology; Tropical diseases; Vectors; Viruses; Waste Water Technology; Water Management; Water Pollution Control; West Nile virus
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-015-4961-1

Microbial control agents offer alternatives to chemical pest control, as they can be more selective than chemical insecticides. The present study evaluates the mosquito larvicidal and pupicidal potential of fungus mycelia using ethyl acetate and methanol solvent extracts produced by Aspergillus terreus against Anopheles stephensi , Culex quinquefasciatus , and Aedes aegypti . The A. terreus mycelia were extracted after 15 days from Sabouraud dextrose broth medium. The ethyl acetate extracts showed lethal concentration that kills 50 % of the exposed larvae (LC 50 ) and lethal concentration that kills 90 % of the exposed larvae (LC 90 ) values of the first, second, third, and fourth instar larvae of An. stephensi (LC 50  = 97.410, 102.551, 29.802, and 8.907; LC 90  = 767.957, 552.546, 535.474, and 195.677 μg/ml), Cx. quinquefasciatus (LC 50  = 89.584, 74.689, 68.265, and 67.40; LC 90  = 449.091, 337.355, 518.793, and 237.347 μg/ml), and Ae. aegypti (LC 50  = 83.541, 84.418, 80.407, and 95.926; LC 90  = 515.464, 443.167, 387.910, and 473.998 μg/ml). Pupicidal activity of mycelium extracts was tested against An. stephensi (LC 50  = 25.228, LC 90  = 140.487), Cx. quinquefasciatus (LC 50  = 54.525, LC 90  = 145.366), and Ae. aegypti (LC 50  = 10.536, LC 90  = 63.762 μg/ml). At higher concentration (500 μg/ml), mortality starts within the first 6 h of exposure. One hundred percent mortality occurs at 24-h exposure. The overall result observed that effective activity against selected mosquito larvae and pupae after 24 h was a dose and time-dependent activity. These ensure that the resultant mosquito population reduction is substantial even where the larvicidal and pupicidal potential is minimal. The FTIR spectra of ethyl acetate extract reflect prominent peaks (3448.32, 3000.36, 2914.59, 2118.73, 1668.21, 1436.87, 1409.02, 954.33, 901.13, and 704.67 cm −1 ). The spectra showed a sharp absorption band at 1314.66 cm −1 assigned to wagging vibration of the C–H group. The band at 1023.59 cm −1 developed for C–O and C=N, respectively, and was commonly found in carboxylic acid and amine groups. GC–MS analysis of ethyl acetate extracts showed the presence of six compounds, of which the major compounds were identified as n -hexadecanoic acid (15.31 %) and methyl 12,15-octadecadienoate (31.989 %), based on their peak molecular weight. The HPLC analysis result highlights that the A. terreus ethyl acetate extract was compared with pure n -hexadecanoic acid which resulted in