Methanolic leaf extract of Cassia fistula was tested for larvicidal and ovicidal activity against Culex quinquefasciatus and Anopheles stephensi. The extract was found to be more lethal to the larvae ...of A. stephensi than C. quinquefasciatus with LC₅₀ values of 17.97 and 20.57 mg/l, respectively. Mean percent hatchability of the ovicidal activity was observed 120 h after treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The egg raft of C. quinquefasciatus was found to be more hatchable than A. stephensi. The results show that the leaf extract of C. fistula is promising as a larvicidal and ovicidal agent against C. quinquefasciatus and A. stephensi.
Entomopathogenic fungi (EPF) are the microorganisms thatspecifically infect and often kill insects and other arthropods. EPF is themost effective biocontrol agent against insects in the natural ...ecosystem whichcould be an effective alternative to chemical insecticides in bio-intensivepest management. Beauveria bassiana, one of the most prevalentsoil-borne entomopathogens, has virulence on insect pests. The present study isaimed to evaluate the pathogenicity of a native isolate of the entomopathogenicfungus B. bassiana isolated from the soil samples of a cotton field(Kuthukkal) in the Tirunelveli district of Tamil Nadu against Dysdercuscingulatus. Bio-efficacy trials were carried out with six differentconcentrations viz., 4.6 × 103,1.5× 104, 5.0 × 105, 2.7 × 106, 3.2 × 107,and 2.8 x 108 (spores/mL) in all the five nymphal instars and theadults of D. cingulatus. A 100% mortality was observed in higherconcentrations 2.8 x 108 (spores/mL) at 120hrs after treatment. The resultsof the present study show that the isolate seems to be highly promising in thepest management of D. cingulatus.
The leaf extract of Acalypha indica with different solvents viz, benzene, chloroform, ethyl acetate and methanol were tested for larvicidal, ovicidal activity and oviposition attractancy against ...Anopheles stephensi. The larval mortality was observed after 24 h exposure. The LC₅₀ values are 19.25, 27.76, 23.26 and 15.03 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 120 h after treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The highest effective attractancy of 90.09%, 94.20%, 85.43% and 95.75% were observed at 100 ppm concentration viz, benzene, chloroform, ethyl acetate and methanol, respectively. The lowest effective attractancy of 47.17%, 61.94%, 49.28% and 68.12% were observed at 25 ppm concentration viz, benzene, chloroform, ethyl acetate and methanol, respectively. The results that the leaf extract of A. indica is promising as larvicidal and ovicidal activity and oviposition attractancy against malaria vector A. stephensi.
Assassin bugs are terrestrial predators belonging to the family Reduviidae. Among the 24 subfamilies, harparctorinae is predominant and extensively investigated for biocontrol applications compared ...to the others subfamilies in Reduviidae. Being natural enemies of phytophagous insects, understanding the phylogeny of these predatory bugs can precise the selection of candidates to employ in insect pest management. In addition to morphological systematics, complete mitochondrial genome sequences provide great insights into the phylogeny for resolving evolutionary complexity. Complete mitochondrial genomes of four potential predatory harpactorinae and one outgroup triatominae were retrieved from NCBI GenBank database. Comparative analysis of the five mitogenomes and the nucleotide sequence between nad1 and nad2 genes were selected as the best option to distinguish. The nucleotide sequence between nad1- nad2 are found to be biased towards A and T similar to their respective complete mitogenomes. Tajima’s test of neutrality suggest that the evolutionary selection at nad1-nad2 was parallel to the complete mitogenome and showed positive and significant (p > 0.1) with high nucleotide diversity. Unequal evolutionary rate at nad1-nad2 between lineages observed in Tajima’s relative rate test and proved the nucleotide sequences of nad1-nad2 between species are highly variable. Comparing the phylogenetic trees generated using the complete mitogenomes and nad1-nad2 genes uncovered the correlation between the trees and having identical branches with varying bootstrap values. Conventionally the highly conserved protein-coding cox1 gene is used for molecular taxonomy whereas this study provides an additional and/or a possible alternative molecular marker for genetic comparative test (the nucleotide sequence between nad1-nad2) to understand the systematics and phylogeny of Reduviidae. The significant nucleotide diversity, high genetic distance and less genetic similarity of the sequence between nad1-nad2 genes among the species studied, Agriosphodrus dohrni, Rhynocoris fuscipes, Scipinia horrida, and Velinus nodipes undoubtedly propose the possible utilization of nad1-nad2 region as distinguishable molecular marker.
The polyphagous, ubiquitous, destructive pest, Spodoptera litura(F.) affects 150 host plant species and notably their larval forms arenotorious. Extensive feeding and rapid reproduction cycles led ...the farmers andindustrialists to seek the effective chemical and synthetic pesticides. Randomand inappropriate usages of pesticides imposed a negative impact on non-targetorganisms, environment and abiotic factors and also pest resurgence to theparticular pesticides. To overcome this unnatural incidence, biopesticides arepracticed as an alternative source. Plant botanicals play a huge role as insectgrowth regulators (IGRs) by inhibiting the regular moulting cycle, developmentand survival of insect pests. Also, the silverback fern, Pityrogramma calomelanosare reported with several secondary metabolites which are known for theirpesticidal properties. Hence, the present work was framed to study the dietaryresponses as well as nutritional indices of S. litura treated with crudeextract of P. calomelanos. The treated larvae showed dietary andpost ingestion responses prior to moulting and death. On the 4th day oftreatment, reduction in food intake (522.89 mg), larval weight gain (41.02 mg),ECI (56.25 %), ECD (46.30 %), AD (47.21 %) and RGR (3.06 mg/mg/day) wasobserved as dose dependent manner except the feacal production (378.18 mg) ascompared to control. Therefore, the ethanolic extract of a fern, P. calomelanoscan be recommended as a biopesticides for its post ingestion andanti-nutritional effects on S. litura larvae.
The benzene extract of Citrullus vulgaris was tested against Anopheles stephensi and Aedes aegypti for the larvicidal activity and ovicidal properties. The crude benzene extract was found to be more ...effective against A. stephensi than A. aegypti. The LC₅₀ values were 18.56 and 42.76 ppm respectively. The LC₅₀ values for silica gel fractions (bioactive fractions I, II, III and IV) were 11.32, 14.12, 14.53 and 16.02 ppm respectively. The mean per cent hatchability of the egg rafts were observed after 48 h post treatment. The crude extract of benzene exerted 100% mortality at 250 ppm against A. stephensi and at 300 ppm against A. aegypti. The silica gel fractions I and II afforded 100% mortality at 100 ppm and III and IV exerted the hatchability rate of 4.9 and 5.3% at the same concentration against A. stephensi.
Essential oils extracted by steam distillation from Cymbopogan citratus were evaluated for larvicidal, ovicidal and repellent activities against the filarial mosquito Culex quinquefasciatus. The ...larval mortality was observed after 24 hours treatment. The LC(50) values calculated for the 2nd, 3rd and 4th larval instar were 144.54 +/- 2.3, 165.70 +/- 1.2 and 184.18 +/- 0.8 ppm respectively. Hundred percent ovicidal activity was observed at 300 ppm. Skin repellent test at 1.0, 2.5 and 5.0 mg/cm(2) concentration of C. citratus gave 100% protection up to 3.00, 4.00 and 5.00 hours respectively. The total percentage of protection of this essential oil was 49.64% at 1.0 mg/cm(2), 62.19% at 2.5 mg/cm(2) and 74.03% at 5.0 mg/cm(2) for 12 hours.
Antibacterial activity of Acalypha indica L Govindarajan, M; Jebanesan, A; Reetha, D ...
European review for medical and pharmacological sciences,
2008 Sep-Oct, Letnik:
12, Številka:
5
Journal Article
Recenzirano
Hexane, chloroform, ethyl acetate and methanol extracts from the leaves of Acalypha indica were tested against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, ...Streptococcus faecalis) and Gram-negative (Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa) bacteria. All the extracts exhibited antibacterial activity against Gram-positive organisms with minimum inhibitory concentrations (MIC) between 0.156 to 2.5 mg/ml. Among the Gram-negative bacteria, only the Pseudomonas aeruginosa was susceptible to the extracts.
The efficacy of the Cucurbitaceous plant Citrullus vulgaris against the Anopheles stephensi was assessed in the present study. The leaf extract of Citrullus vulgaris with different solvents viz, ...benzene, petroleum ether, ethyl acetate and methanol were tested for larvicidial, ovicidal, repellent and insect growth regulatory activities against Anopheles stephensi. The larval mortality was observed after 24 h exposure. The LC50 values are 18.56, 48.51, 49.57 and 50.32 ppm respectively. The mean percent hatchability of the egg of Anopheles stephensi were observed after 48 h. 100 per cent mortality was exerted at 250 ppm with benzene extract and the other extracts exerted 100 percent mortality at 300 ppm. Skin repellent test at 1.0, 2.5 and 5.0 mg per cm2 concentration gave the mean complete protection time ranged from 119.17 to 387.83 minutes with the four different extracts tested. The Citrullus vulgaris plant extract have shown insect growth regulatory activity against Anopheles stephensi at five different test concentrations ranging from 10 to 150 ppm with different solvents and they exhibit the following EI50 values 28.99, 70.02, 106.33 and 84.25 ppm respectively.
