Synthesis and Insecticidal Activity of Derivants of 3,13-Ester Mesaconitine

[Objective] The experiment aimed to explore the relations between structure of aconitine, aconitine derivatives and insecticide. [Method] The aconitine derivatives such as 3-acetyl mesaconitine, 3-propionyl mesaconitine, 3-acetyl-13-Benzoyl-mesaconitine and 3-propionyl-13-Benzoyl-mesaconitine were synthesized by mesaconitine with acetic anhydride or propionic anhydride and their insecticidal activities were also determined. [Result] When the concentration was 500 mg/L, the insecticidal activities of mesaconitine against Nilaparvata legen and Aphis were 50% and 30% respectively while the insecticidal activities of 3-acetyl mesaconitine, 3-propionyl mesaconitine, 3-acetyl-13-Benzoyl-mesaconitine and 3-propionyl-13-Benzoyl-mesaconitine against Aphis medicagini were 40%, 30%, 30% and 20% respectively at 500 mg/L. [Conclusion] After hydroxyl esterification, the insecticidal activity of mesaconitine was declined and the existence of hydroxyl at 3rd position in mesaconitine played very important influences on insecticidal activity.

Expression, Purification and Insecticidal Activity Analysis of Cry1Ac without Helix α-1

[Objective] This study aimed to analyze the expression, purification and insecticidal activity of Cry1Ac without helix α-1 of domain I in E. coli. [Method] Plasmid of B. thuringiensis HD-1 was used as the template for amplification of Cry1Ac gene, which was linked with pET28a vector to construct the recombinant plasmid. After transformation and IPTG induction, expression of target protein was detected by using SDS-PAGE method. Target protein was extracted and coated on the surface of feed for H. armigera to determine the insecticidal activity. [Result] Cry1Acdela1 gene could normally express the target protein in E. coli. However, the target protein existed in the form of inclusion body. Results of bioassay analysis showed that under the same concentration, fatality rate of activated Cry1Ac toxin reached above 75%, while that of Cry1Acdelα1 was only about 10%. [Conclusion] E. coli-expressed Cry1Acdelα1 had no insecticidal activity against H. armigera.

Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus cirri was tested in the laboratory. Four solvents were used to prepare crude extracts, petroleum ether, chloroform, ethyl acetate, and ethanol, among which ethanol was the most effective one. The results suggested that ethanol extracts of B. sessilicarpa had eminent acaricidal and ovicidal activities. Concentrated extracts were prepared using petroleum ether, chloroform, ethyl acetate, or distilled water as solvent. Mite mortality rates in the concentrated extracts by petroleum ether, chloroform, or distilled water were significantly lower than those by ethyl acetate. The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL^-1, respectively. After liquid chromatography and thin layer chromatography, the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted. Fraction 2 was found to possess higher acaricidal and ovicidal activities. The mortality of eggs and adult mites were 85.83 and 63.07%, respectively. Moreover, fraction 2 showed moderate oviposition inhibition effect （0.8795） against P. citri when the used dose was higher than 2.5 mg mL^-1

Acaricidal activity of Derris floribunda essential oil and its main constituent

Objective: To evaluate the acaricidal activity of the essential oil obtained from roots of Derris floribunda(D. floribunda)(Miq.) Benth, and its main constituent nerolidol against the Mexican mite Tetranychus mexicanus(T. mexicanus)(Mc Gregor).Methods: The essential oil from the roots of D. floribunda collected in the Amazon region(Brazil) was obtained by hydrodistillation. Its chemical composition was determined by GC–MS analysis. The acaricidal activities of this essential oil and nerolidol,were evaluated by recording the number of dead females(mortality) and eggs(fertility).Results: The essential oil showed sesquiterpenes as major volatile components. Nerolidol, the main component, represented 68.5% of the total composition of the essential oil. D. floribunda essential oil and nerolidol showed acaricidal activity, with LC_(50) of9.61 mg/m L air and 9.2 mg/m L air, respectively, over a 72 h period. In addition, both the essential oil and nerolidol significantly reduced the fecundity of T. mexicanus.Conclusions: Due to the economic importance of T. mexicanus and the lack of new pesticides, our data are very promising in the search for efficient and safer acaricidal products. Furthermore, this is the first report about the chemical composition and bioactivity of the essential oil of the Amazon plant species D. floribunda.

Purification, characterization and evaluation of insecticidal activity of trypsin inhibitor from Albizia lebbeck seeds

A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.I M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion ex- change chromatography on DEAE-Sephadex As0. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60~C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 ~tM. The inhibitoi- was found to be susceptible to varying concentrations of reducing agents like DTT and 2- mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth ofPieris brassi- cae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.

Synthesis,Crystal Structure and Insecticidal Activity of N-(pyridin-2-ylmethyl)-1-phenyl-1,4,5,6,7,8-hexahydrocyclohepta[c]pyrazole-3-carboxamide

The title compound N-（pyridin-2-ylmethyl）- 1-phenyl- 1,4,5,6,7,8-hexahydrocy-clohepta[c]pyrazole-3-carboxamide 5 （C21I-I22N40, Mr = 346.42） has been synthesized andstructurally characterized by IR, 1H NMR, 13C NMR, H RMS and single-crystal X-raydiffraction. The crystal crystallizes in monoclinic system, space group P21/n with a = 8.668（2）,b = 22.236（4）, c = 9.539（2） A, β = 108.68（3）°, V = 1786.4（7）/k3, Z = 4, Dx= 1.288 g/cm3,F（000） = 736,μ（MoKa） = 0.649 mm^-1, the final R = 0.0354 and wR = 0.0933 with 3234observed reflections with I 〉 2σ（/）. The benzene and pyrazole rings are nearly coplanar with adihedral angle of 50.977（46）°. The dihedral angle between the central pyrazole and pyridinerings is 11.688（46）°. No classical hydrogen bonds were found in the molecules. Two adjacentmolecules in crystal packing of compound 5 were linked by two intramolecularhydrogen-bonding interactions C（15）-H（15）…O（1） to generate a stable structure. Compound 5had weak insecticidal activity against the diamondback moth （Plutella xylostella）, butexhibited good activity against cotton bollworm （Helicoverpa armigera）.

Diamide derivatives containing a trifluoromethylpyridine skeleton:Design,synthesis,and insecticidal activity

Diamide derivatives are biologically active molecules that have been widely applied in recent years in research on pesticides,especially insecticides.Using a simple and environmentally friendly scheme,a series of new diamide derivatives containing a trifluoromethylpyridine skeleton was designed,synthesized,and confirmed by^(1)H,^(19)F and^(13)C NMR,and HR-MS.Their insecticidal activities against Plutella xylostella and Helicoverpa armigera were measured and the relationship between structure and activity was investigated.Eight of the title compounds(D2,D5,D10,D21,D28,D29,D30 and D33)showed 100%activity against P.xylostella at 500 mg L^(-1).One compound,D33,still showed 100%activity against P.xylostella at 100 mg L^(-1)and had the lowest LC_(50)(lethal concentration 50%,3.7 mg L^(-1))among the synthesized compounds.Molecular docking analysis revealed that D33 could be thoroughly embedded in the active pocket of the ryanodine receptor via hydrogen bonding in a manner similar to the commercial insecticide chlorantraniliprole.

Study on Chemical Synthesis and Insecticidal Activity of Peptideκ-CTx-btg02

[Objectives]This study was conducted to investigate the chemical synthesis of peptideκ-CTx-btg02.[Methods]Linear peptideκ-CTx-btg02 was synthesized by solid phase peptide synthesis(SPPS).After oxidation and folding of the linear peptide,mass spectrometry identification and high performance liquid chromatography(HPLC)purification were performed.Then,the MTT method and insect injection method were applied to study its insecticidal activity.[Results]The peptideκ-CTx-btg02 was successfully synthesized by the SPPS method,and identified for the formation of disulfide bonds by mass spectrometry identification,and the purity after HPLC separation was greater than 95%.The MTT experiment showed that the peptideκ-CTx-btg02 could inhibit the growth of insect cells sf9,with a half effective dose of 0.13 nM.The insect injection experiment showed that the peptideκ-CTx-btg02 could effectively kill Tenebrio molitor,with a half lethal dose of 15.6 nM.The results of the electrophysiological experiment showed that 10μM peptideκ-CTx-btg02 had no blocking activity on murine acetylcholineα2β3 andα3β4.Therefore,the peptideκ-CTx-btg02 had a good inhibitory effect on the growth of insect cells,highly effective insecticidal activity and weak mammalian toxicity.[Conclusions]This study lays a foundation for the development of new,safe and efficient peptide biological insecticides.

Ethnobotanical Investigation of Insecticidal Plants and Evaluation of the Insecticidal Activity of Capsicum chinense on Sitophilus zeamaïs of Maize and Aphis craccivora of Groundnuts: Case of Boffa, BokéRegion (Republic of Guinea)

The present study, which aims to contribute to the valorization of Capsicum chinense, focuses on ethnobotanical investigations and evaluation of insecticidal activity on Sitophilus zeamaïs and Aphis craccivora, as well as the germination power of infected maize and peanut grains treated and not treated with Capsicum chinense leaf powder. To do this, the moisture content of corn and peanuts was determined by the techniques: drying in the sun and in the oven. The insecticidal effect of the powder was tested on maize and peanut kernels infected by the AGRAR (2013) method, followed by a test of the germination potency of these treated grains. The average moisture values of corn and groundnut kernels are 14.51% and 12.25% respectively. The results show, a higher insecticidal efficacy of Capsicum chinense leaf powder on Sitophilus zeamaïs and Aphis craccivora with doses (2, 4 and 8 g). The average germination rates of maize and peanut kernels infected and treated with this powder are: (16.5%;63%;99.5%) and (21.25%;96.5%;99.75%), respectively. This study could be a bio-insecticide alternative for the peasant community in the conservation of cereal and legume products.

Synthesis,Structure and Acaricidal Activity of Tricyclohexyltin Benzoate

Tricyclohexyltin 4-amino-3-methyl-benzoate （1） and tricyclohexyltin 3,4-dime- thoxybenzoate （2） were synthesized and their crystal structures were determined by X-ray diffraction. Compound 1 belongs to the monoclinic system, space group P21/c with a = 14.0554（15）, b = 11.6947（13）, c = 16.2720（17）A, Z = 4, V= 2565.7（5） A3, Dc = 1.341 g.cm-3,μ（MoKa） = 1.016 mm-1, F（000） = 1080, R = 0.0833 and wR = 0.2964. Compound 2 is of monoclinic system, space group C2/c with a = 17.8712（6）, b = 8.4433（3）, c = 35.5783（13） A, Z = 8, V= 5366.8（3） A3, Dc = 1.360 g.cm-3,/1（MoKa） = 0.980 mm-1, F（000） = 2288, R = 0.0549, wR = 0.1279. In compounds 1 and 2, the central Sn atom is coordinated in a tetradentate manner to assume a distorted tetrahedral configuration. Preliminary biological tests showed that these two compounds have strong acaricidal activity.

Insecticidal Activity and Field Efficacy of Novel Insecticide Cyhalodiamide against Different Lepidoptera Pests

[ Objective] The paper was to study the insecticidal activity and field efficacy of cyhalediamide, a novel insecticide developed by Zhejiang Research Institute of Chemical Industry, Ltd. [ Method] Toxicity of cyhalodiamide against Plutella xylostella, Spodoptera exigua, Prodenia litura and Chilo suppressalis were tasted in the laboratory by leaf-dipping method, and the field efficacy of cyhalodiamide against P. xylostella, S. exigua, P. litura, Pieris rapae, C. suppressalis and Cnaphalocrocis medinalis was evaluated. [ Result] The LCs0 values of cyhalodiamide against P. xylostella, S. exigua, P. litura and C. suppressalis were 0. 046, 0.072, 0.071 and 1.95 mg/L, respectively, almost equivalent to that of flubendiamide and ehlorantraniliprole. The control efficacy of 20% Z4042 SC （30 g/hm2） against P. xylostella, S. exigua, P. litura and P. rapae was 90.1% - 96.3 % after spraying for 7 d, and its control efficacy against C. suppressalis and C. medinalis was 82.9% -90.5% after spraying for 15 d. No crop injury was observed at the test dosage. [Conclusion] The study provided reference for field control against Lepidoptera pests.

Insecticidal Activity of Crystals and Spores of Purified Bacillus thuringiensis 00-50-5 Strain against Trichoplusia ni Hubner

[ Objective] The paper was to study pathogenic mechanism and action mode of Bacillus thuringiensis （Bt） 00-50-5 strain against Trichoplusia ni Hub- ner. [Method] The crystals and spores of B. thuringiensis 00-50-5 strain were first isolated and purified, and their insecticidal activities against T. ni were com- pared. [ Result] Either the mixture of pure crystals and pure spores of 00-50-5 strain, or only pure crystals could kill T. n/larvae under the concentration of 100 p.g/mL after 48 h, and the mortality rate reached 100% ; pure spores could not kill the larvae. Determination results of median lethal concentration showed that in- secticidal activity of pure crystal of Bt 00-50-5 strain （LGs0 =0.32 p~/mL） was higher than the mixture of crystals and spores （LCs0 =0.48）, but the insecticidal acti^ty of pure spores was very low （LC50 〉 500.00）. Therefore, the crystals were primarily responsible for causing death of larvae. [ Conclusion] The paper provides theoretical basis for application of Bt 00-50-5 strain.

Insecticidal Activity of Piperine Isolated from Piper sarmentosum

In order to clarify the insecticidal active ingredients of Piper sarmentosum,one active ingredient was isolated from ethanol extract of P. sarmentosum by bioassay-guided fractionation method. Its chemical structures were identified to be piperine by MS,1H NMR,13C NMR. The insecticidal activity of piperine and ethanol extract of P. sarmentosum against Aleurodicus dispels Russell were tested by leaf dip method. The results showed that piperine and ethanol extract of P. sarmentosum exhibited strong insecticidal activity against adults and nymphs of A. dispels; LC50values against adults were 28. 59 and 224. 31 mg/L,and LC50values against nymphs were 65. 91 and 336. 68 mg/L,respectively. There was no significant difference between piperine and azadirachtin against adults and nymphs of A.dispels. Therefore,piperine might be one of the main insecticidal ingredients of P. sarmentosum. In addition,piperine and ethanol extract showed ovicidal activity with different mode of action,piperine reduced the survival rate of newly hatched nymphs while ethanol extract impacted hatch of eggs.

Insecticidal Activity of <i>Bacillus thuringiensis</i>on Larvae and Adults of <i>Bactrocera oleae Gmelin</i>(Diptera:Tephritidae)

The olive fruit fly Bactrocera oleae is a major olive pest in Algeriaand other Mediterranean countries. Its attacks, in some cases, seriously compromised production. Bacillus thuringiensis is a spore-forming soil bacterium which produces a protein crystal toxic to some insects. The objective of this study was to search for isolates toxic to larvae and adults of B. oleae. Four doses test were performed on neonate larvae, second instar larvae and third instar larvae. Seven Bt strains examined, showed highest toxicity levels against adults. 86% mortality was observed against neonate larvae after 7 days of application by Bt toxin isolate. The mortality of the second instar larvae was 65% mortality at dose of 108 UFC/mL. The third instar larvae was very susceptible to Bt strain with 70% of mortality. This study demonstrated that some local Algerian B. thuringiensis isolates exhibit toxic potential that could be used to control B. oleae.

Bioactive Compounds and Insecticidal Activity of Hysterionica pinifolia, a Native South American Plant

Phytochemical investigation of the purified fractions of the active dichloromethane extract of Hysterionica pinifolia (Poir.) Baker led to the identification of five compounds. New acetylenic alcohol (E)-undec-3-en-5,7-diyne-1-ol (1) and three other compounds (3), (4), and (5) were reported for the first time in this species. Furthermore, forty-six components from the volatile fraction of H. pinifolia were identified. These compounds were elucidated using 1D and 2D NMR spectroscopy as well as MS-ESI and GC-FID-MS experiments. The dichloromethane extract, its fractions, and the methanolic extract were tested for insecticidal activity against Tribolium castaneum under laboratory conditions. The dichloromethane extract and the fraction F2 were found to be active, showing high larval mortality. The dichloromethane extract was also active against T. castaneum adults. The results have shown that H. pinifolia could be considered, in a near future, as a potential source for the development of a botanical insecticide for pest control.

Insecticidal Activity of an Indian Botanical Insecticide ULTRA ACT&#174 against the Olive Pest <i>Bactrocera oleae</i>(Diptera: Tephritidae) in Tunisia

Bactrocera oleae is the most economically damaging insect of olive in the Mediterranean. As a reliable alternative to synthetic chemical insecticides, botanical pesticides from plant extracts are also considered natural control methods safe for the environment and human health. In practical applications up to date, studies demonstrating toxically effects of biological control agents on the insect have been carried out in organic farming systems based on some industrial microbial formulations. But much less attention has been given to botanical insecticides against B. oleae. Thus, a certified botanical insecticide issue from various plants and approved per Indian and International organic standards was tested against larvae and pupae of the olive pest Bactrocera oleae in the east of Tunisia under laboratory conditions. The experiments were conducted with 3 normal treatments and 1 control. Two techniques were used for larvae and pupae: direct contact using concentration from 0.5;0.750;1 and 1.5 mg/l and fumigation treatment using 2 mg/l conducted in rectangular boxes (25&#176C - 27&#176C, 75% - 85% RH and 14:10 LD photo period). For larval stages, LC50 and LC90 values for Ultra-Act were 0.45 and 1.22 mg/L in direct contact and 1.5 - 2 mg/l with fumigation, respectively. For pupal stage, the ID25 and ID50 values were estimated to be 0.71 mg and 1.26 mg respectively corresponding to the inhibition of emergence of 25% and 50% of B. oleae adults from pupa. Our results indicate that sprayed Ultra-Act product has the potential to control the three olive fly instar larvae. Pupal emergency was decreased significantly with fumigation treatment. In conclusion, Ultra-Act is a promising botanical insecticide against B. oleae that could be used as a successful alternative for chemicals in integrated control methods of this pest in Tunisia.

Preparation of Sea Anemone Peptide Toxin Ap-TxI and Its Insecticidal Activity

[Objectives]This study was conducted to synthesize sea anemone peptide toxin Ap-TxI and investigate its insecticidal activity. [Methods] The sea anemone linear peptide toxin Ap-TxI was synthesized by the solid-phase peptide synthesis(SPPS), and six cysteines were oxidized to form three disulfide bonds by a three-step directional oxidation method. Then, purification by high performance liquid chromatography(HPLC) and mass spectrometry identification were performed. Finally, the insect cytotoxicity and insecticidal activity of Ap-TxI were studied by the MTT method and insect injection method. [Results] The oxidized peptide Ap-TxI with three disulfide bonds in natural configuration was successfully synthesized by the SPPS method, and its purity was >90% by HPLC analysis. The results of the MTT method showed that Ap-TxI was active on the growth of insect cells sf9, with a half effective dose of 0.2 nM;and the results of the mealworm injection test showed that the polypeptide Ap-TxI had high insecticidal activity with a median lethal dose of 11.7 nM. [Conclusions] The sea anemone peptide toxin Ap-TxI with high insecticidal effect was obtained, laying a foundation for the development of new, efficient and safe biological insecticides.

Preparation and Insecticidal Activity of Sea Anemone Peptide AP-GI from Aiptasia pallida

[Objectives] This study was conducted to synthesize sea anemone peptide Ap-GI and investigate its insecticidal activity. [Methods] The linear peptide Ap-GI was synthesized by solid phase peptide synthesis(SPPS), and the linear peptide was subjected to the two-step oxidative folding, mass spectrometry identification and high performance liquid chromatography(HPLC) purification. Then, the MTT method and insect injection method were used to study its insecticidal activity. [Results] The synthesized sea anemone peptide had a purity of 95%. The test results of the MTT method showed that the peptide Ap-GI had the activity of inhibiting the growth of insect cells sf9 with the median effective dose of 0.7 nM;and the test results of the injection method on yellow mealworms showed that the peptide Ap-GI had high insecticidal activity, and the median lethal dose was 16.9 nM. [Conclusions] The sea anemone peptide Ap-GI from Aiptasia pallida has a good inhibitory effect on the growth of insect cells and high-efficiency insecticidal activity, which can lay a foundation for the development of new, safe and efficient peptide biological insecticides.

Evaluation of the Insecticidal Activity of the Aerial Part of Pseudocytisus integrifofius （Salisb） Rehder on Grain Borer, Rhyzopertha dominica Fab, （Bostrychidae） and Wheat Weevil, Sitophilus granarius Linn, （Curculionidae）

This study aims to evaluate the potentialities of Pseudocytisus integrifolius （Salisb） Rehder （Brassicaceae） as a botanical insecticide for the protection of stored wheat against two pests of stored grain. The essential oil of Pseudoeytisus integrifolius was tested at different doses on adults of Rhyzopertha dominica Fab. （Bostrychidae） and Sitophilus granarius Linn. （Curculionidae）, at a temperature of 28 ~C and a relative humidity of 75%. This oil has insecticidal activity and gives, for the studied adults, a very significant reduction. The essential oil extracted from Pseudocytisus integrifolius is toxic on Rhyzopertha dominica with LDs0 = 2.61 ~tL/30g grain and LDs0 = 3.99 ~L/30g grain for Sitophilus granarius, the chemical composition analysis shows the richness of the essential oil compounds known for their insecticidal properties as dimethyl disulfide （DMDS） and dimethyl trisulfide explains the results.

Evaluation of the Insecticidal Activity of Powders of Ageratum conyzoide L. Leaves and Roots of Securidaca longepedunculata Fresen on the Germination Rate of Cowpea Infected with Callosobruchus maculatus

Cowpea is a vegetable that contributes to food security in Guinea. Despite its importance, more than 30% of its production is lost between harvesting, storage and consumption. The main cowpea pest is Callosobruchus maculatus. The commonly used control strategy is essentially based on chemicals whose use is toxic, expensive and restrictive. In the search for alternatives to chemical control, this work was undertaken to evaluate the insecticidal potential of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots. Powder toxicity and insecticidal efficacy tests were performed separately on groups of 20 Callosobruchus maculatus using 3 doses of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots in jars each containing 100 g cowpea. The mortality of Callosobruchus maculatus and the impact of powders were noted respectively for 96 h and 4 months after infestation. The germination capacity of the treated seeds was assessed at the start of the study. Doses of 1 and 8 g of Ageratum conyzoides leaf powders and Securidaca longepedunculata roots were applied respectively to every 100 g of cowpea and led to 100% mortality of Callosobruchus maculatus. At these same doses, more than half of the treated seeds were attacked during the 4 months of storage. Germination tests have shown that powders of Ageratum conyzoides leaves and roots of Securidaca longepedunculata have no negative effect on the germination power of cowpea seeds. Therefore, they could be considered as excellent bio-insecticides that socio-professional strata (farmers and warehouse workers) can use in the fight against cowpea insects intended for storage.