OBJECTIVES: To investigate how larval feeding regimens influence development and deltamethrin resistance of Aedes albopictus to provide evidence for standardizing larval feeding protocols in studies of insecticide resistance. METHODS: Aedes albopictus larvae of a laboratory resistant strain were divided into 3 groups (n=500) and reared with high, medium, and low food availability (100, 50, or 25 mg daily for the 1st and 2nd instars, and 500 mg 250, or 125 mg daily for 3rd and 4th instars). The developmental time, pupation rate, adult emergence rate, adult body weight, and wing length were recorded in each group, and deltamethrin resistance of the mosquitoes was assessed using larval bioassays and contact tube tests for adults. RESULTS: Significant developmental differences were observed across the 3 feeding groups. Larval development time decreased as the food availability increased, and both high- and low-food groups showed reduced pupation rates (χ²=16.282, 7.440) and emergence rates (χ²=4.093, 6.977) compared to the medium-food group. Adult body weight and wing length were positively correlated with the amount of larval food intake (P<0.05). In high, medium and low food intake groups, larval LC₅₀ values for deltamethrin were 0.110, 0.072 and 0.064 mg/L, adult KDT50 values were 97.404, 68.964 and 65.005 min, and adult mosquitoe mortality rates at 24 h after deltamethrin exposure were 12%, 16% and 19%, respectively. CONCLUSIONS The feeding amount during larval stage significantly impacts the development and deltamethrin resistance of Aedes albopictus, suggesting the importance of standardization of larval nutrition for ensuring comparability of resistance test data across laboratories.
Animals ; Aedes/physiology* ; Pyrethrins/pharmacology* ; Nitriles/pharmacology* ; Larva/physiology* ; Insecticide Resistance ; Insecticides/pharmacology* ; Feeding Behavior

Bt Cry toxin is the mostly studied and widely used biological insect resistance protein, which plays a leading role in the green control of agricultural pests worldwide. However, with the wide application of its preparations and transgenic insecticidal crops, the resistance to target pests and potential ecological risks induced by the drive are increasingly prominent and attracting much attention. The researchers seek to explore new insecticidal protein materials that can simulate the insecticidal function of Bt Cry toxin. This will help to escort the sustainable and healthy production of crops, and relieve the pressure of target pests' resistance to Bt Cry toxin to a certain extent. In recent years, the author's team has proposed that Ab2β anti-idiotype antibody has the property of mimicking antigen structure and function based on the "Immune network theory" of antibody. With the help of phage display antibody library and specific antibody high-throughput screening and identification technology, Bt Cry toxin antibody was designed as the coating target antigen, and a series of Ab2β anti-idiotype antibodies (namely Bt Cry toxin insecticidal mimics) were screened from the phage antibody library. Among them, the lethality of Bt Cry toxin insecticidal mimics with the strongest activity was close to 80% of the corresponding original Bt Cry toxin, showing great promise for the targeted design of Bt Cry toxin insecticidal mimics. This paper systematically summarized the theoretical basis, technical conditions, research status, and discussed the development trend of relevant technologies and how to promote the application of existing achievements, aiming to facilitate the research and development of green insect-resistant materials.
Insecticides/metabolism* ; Bacillus thuringiensis ; Endotoxins/pharmacology* ; Bacillus thuringiensis Toxins/metabolism* ; Hemolysin Proteins/pharmacology* ; Bacterial Proteins/chemistry* ; Plants, Genetically Modified/genetics* ; Pest Control, Biological

Bacillus thuringiensis is widely used as an insecticide which is safe and environmentally friendly to humans and animals. One of the important insecticidal mechanisms is the binding of Bt toxins to specific toxin receptors in insect midgut and forming a toxin perforation which eventually leads to insect death. The resistance of target pests to Bt toxins is an important factor hampering the long-term effective cultivation of Bt crops and the continuous use of Bt toxins. This review summarizes the mechanism of insect resistance to Bt toxins from the perspective of important Bt toxin receptors in midgut cells of Lepidopteran insects, which may facilitate the in-depth study of Bt resistance mechanism and pest control.
Animals ; Bacillus thuringiensis/genetics* ; Bacillus thuringiensis Toxins ; Bacterial Proteins/metabolism* ; Endotoxins/metabolism* ; Hemolysin Proteins/metabolism* ; Insecta/metabolism* ; Insecticide Resistance/genetics* ; Insecticides/pharmacology* ; Pest Control, Biological

This paper is in order to study the anti-feeding and growth inhibition activity of toatal ginsenoside of ginseng stems and leaves against 4th-instar Mythimna separata larvae. Simulating natural growing condition indoors, on the base, To study the anti-feeding and growth inhibition activity of toatal ginsenoside against 4th-instar M. separata larvae by leaf disc test. The toatal ginsenoside appeared to be of significant antifeeding activity against 4th-instar M. separata larvae. The 4th-instar M. separata larvae fed on the leaves of Sorghum bicolor treated with 20, 10, 5 g · L(-1) toatal ginsenoside. At 8 h, non-selective anti-feeding rate were 88.67%, 64.40% and 47.36%, and selective anti-feeding rate were 62.49% , 44.29% and 34.19%; Compared with the photographic, The toatal ginsenoside conld make the development period had prolonged 13h in treated group. The toatal ginsenoside had significant inhibition effect on feeding and growth and development against 4th-instar M. separata larvae, and inhibition effect increases as the increase of concentration ginsenoside.
Animals ; Ginsenosides ; pharmacology ; Insecticides ; pharmacology ; Larva ; Moths ; growth & development ; Panax ; chemistry

Essential oils of the resins of Pinus brutia and Pinus pinea were evaluated for their biological potential. Essential oils were characterized using GC-MS and GC/FID. in vitro antimicrobial, phytotoxic, antioxidant, and insecticidal activities were carried out using the direct contact and the fumigant assays, respectively. The chemical profile of the essential oils of the resins of P. pinea and P. brutia included mainly α-pinene (21.39% and 25.40%), β-pinene (9.68% and 9.69%), and caryophyllene (9.12% and 4.81%). The essential oils of P. pinea and P. brutia exerted notable antimicrobial activities on Micrococcus luteus and Bacillus subtilis, insecticidal activities on Ephestia kuehniella eggs, phytotoxic activities on Lactuca sativa, Lepidium sativum, and Portulaca oleracea, as well as antioxidant potential. Indications of the biological activities of the essential oils suggest their use in the formulation of ecofriendly and biocompatible pharmaceuticals.
Animals ; Anti-Infective Agents ; analysis ; pharmacology ; Antioxidants ; analysis ; pharmacology ; Bacillus subtilis ; drug effects ; Bicyclic Monoterpenes ; Bridged Bicyclo Compounds ; analysis ; pharmacology ; Gas Chromatography-Mass Spectrometry ; Insecta ; drug effects ; Insecticides ; analysis ; pharmacology ; Lepidium ; drug effects ; Lettuce ; drug effects ; Mediterranean Region ; Micrococcus luteus ; drug effects ; Monoterpenes ; analysis ; pharmacology ; Oils, Volatile ; chemistry ; pharmacology ; Pinus ; chemistry ; Plant Extracts ; chemistry ; pharmacology ; Plant Oils ; chemistry ; pharmacology ; Polycyclic Sesquiterpenes ; Portulaca ; drug effects ; Resins, Plant ; chemistry ; Sesquiterpenes ; analysis ; pharmacology ; Terpenes ; analysis ; pharmacology

OBJECTIVETo evaluate the efficacy of Atalantia monophylla (A. monophylla) leaf in different solvent crude extracts and fractions against eggs of Spodoptera litura (S. litura).

METHODSHexane, ethyl acetate and chloroform solvent extracts of A. monophylla leaf and 12 fractions from hexane extract were screened at 5.0%, 2.5%, 1.0% and 0.5% for crude extracts and 1 000, 500, 250 and 125 mg/kg for fractions against the eggs of S. litura for the ovicidal activity. LC50 and LC90 were calculated using probit analysis.

RESULTSHexane crude extract showed maximum ovicidal activity of 61.94% at 5.0% concentration with a correlation value of r (2)=0.81, and least LC50 value of 3.06%. Hexane extract was fractionated using silica gel column chromatography and 12 fractions were obtained. Fraction 9 was active which showed maximum ovicidal activity of 75.61% at 1 000 mg/kg with the LC50 value of 318.65 mg/kg and LC90 value of 1 473.31 mg/kg. In linear regression analysis, significant and high correlation (r (2)=0.81%) was seen between concentration and ovicidal activity of hexane crude extracts and its active fraction.

CONCLUSIONSAs per our knowledge, this is the first report for ovicidal activity of A. monophylla against S. litura, A. monophylla could be used for the management of S. litura and other insect pests.

Animals ; Biological Assay ; Hexanes ; chemistry ; Humans ; Insecticides ; pharmacology ; Lepidoptera ; drug effects ; growth & development ; Plant Extracts ; pharmacology ; Plant Leaves ; chemistry ; Rutaceae ; chemistry ; physiology ; Spodoptera ; drug effects ; growth & development

OBJECTIVETo evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera).

METHODSHexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera.

RESULTSEthyl acetate extract showed promising antifeedant and insecticidal activities against S. litura and H. armigera. Percentage of deformed larvae, pupae and adults were maximum in treatment of ethyl acetate extract. Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae.

CONCLUSIONSEthyl acetate extracts of S. pseudocapsicum, showed higher efficiency of antifeedant, insecticidal and growth inhibition activities. Hence, it can be used to controll agricultural insect pests, S. litura and H. armigera.

Animals ; Humans ; Insecticides ; pharmacology ; Larva ; drug effects ; growth & development ; Lethal Dose 50 ; Moths ; drug effects ; growth & development ; Pest Control ; Plant Extracts ; pharmacology ; Solanaceae ; chemistry ; Spodoptera ; drug effects ; growth & development

OBJECTIVETo evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus.

METHODSThe mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol. The wide range concentration tested in the present study was 10 000, 1 000, 100, 10 and 1 mg/L and narrow range concentration was 50, 100, 150, 200 and 250 mg/L.

RESULTS2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100% mortality. Remaining stages such as 3rd, 4th and pupa, 100% mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period. In aqueous extract all the stages 100% mortality was recorded at 1 000 mg/L and above concentration. In narrow range concentration 2nd instar larvae 100% mortality was observed at 150 mg/L and above concentration of ethanol extract. The remaining stages 100% mortality was recorded at 250 mg/L. In aqueous extract all the tested immature stages 100% mortality was observed at 250 mg/L concentration after 24 h exposure period. The results clearly indicate that the rate of mortality was based dose of the plant extract and stage of the mosquitoes.

CONCLUSIONSFrom this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus. The isolation of bioactive molecules and development of simple formulation technique is important for large scale implementation.

Animals ; Cassia ; chemistry ; Culex ; drug effects ; growth & development ; Insecticides ; chemistry ; pharmacology ; Lethal Dose 50 ; Life Cycle Stages ; Plant Extracts ; chemistry ; pharmacology ; Plants, Medicinal ; chemistry

OBJECTIVETo investigate the theoretical model of the three-dimensional structure of mosquitocidal Cry30Ca2 and its molecular docking with N-acetylgalactosamine.

METHODSThe theoretical model of Cry30Ca2 was predicted by homology modeling on the structure of the Cry4Ba. Docking studies were performed to investigate the interaction of Cry30Ca2 with N-acetylgalactosamine on the putative receptor.

RESULTSCry30Ca2 toxin is a rather compact molecule composed of three distinct domains and has approximate overall dimensions of 95 by 75 by 60Å. Domain II is a helix bundle, Domain II consists of three antiparallel β-sheets, Domain III is composed of two β-sheets that adopt a β-sandwich fold. Residue 321Ile in loop1, residues 342Gln 343Thr and 345Gln in loop2, residue 393Tyr in loop3 of Cry30Ca2 are responsible for the interactions with GalNAc via 7 hydrogen bonds, 6 of them were related to the oxygen atoms of hydroxyls of the ligand, and one to the nitrogen of the ligand.

CONCLUSIONThe 3D structure of Cry30Ca2 resembles the previously reported Cry toxin structures but shows still some distinctions. Several residues in the loops of the apex of domain II are responsible for the interactions with N-acetylgalactosamine.

Acetylgalactosamine ; chemistry ; Amino Acid Sequence ; Animals ; Bacterial Proteins ; chemistry ; pharmacology ; Catalytic Domain ; Culicidae ; drug effects ; Endotoxins ; chemistry ; pharmacology ; Hemolysin Proteins ; chemistry ; pharmacology ; Insecticides ; chemistry ; pharmacology ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation

OBJECTIVETo assess the larvicidal and irritant activities of the hexane extracts of leaves of Citrus sinensis (C. sinensis) against the early fourth instars and female adults of Aedes aegypti (Ae. aegypti).

METHODSThe larvicidal potential of the prepared leaf extract was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 h and LC50 and LC90 values were calculated. The efficacy of extract as mosquito irritant was assessed by contact irritancy assays. Extract-impregnated paper was placed on a glass plate over which a perspex funnel with a hole on the top was kept inverted. Single female adult, 3-day old unfed/blood-fed, was released inside the funnel. After 3 min of acclimatization time, the time taken for the first take-off and total number of flights undertaken during 15 min were scored.

RESULTSThe citrus leaf extracts from hexane possessed moderate larvicidal efficiency against dengue vector. The bioassays resulted in an LC50 and LC90 value of 446.84 and 1 370.96 ppm, respectively after 24 h of exposure. However, the extracts were proved to be remarkable irritant against adults Ae. aegypti, more pronounced effects being observed on blood-fed females than unfed females. The extract-impregnated paper was thus proved to be 7-11 times more irritable as compared with the control paper.

CONCLUSIONSThe hexane extracts from C. sinensis leaves are proved to be reasonably larvicidal but remarkably irritant against dengue vector. Further studies are needed to identify the possible role of extract as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the extract could help in formulating strategies for mosquito control.

Aedes ; drug effects ; Animals ; Citrus sinensis ; metabolism ; Dengue ; transmission ; Disease Vectors ; Female ; Insecticides ; pharmacology ; Larva ; drug effects ; Mosquito Control ; methods ; Plant Extracts ; pharmacology ; Plant Leaves ; metabolism