Security and Privacy in Solar Insecticidal Lamps Internet of Things:Requirements and Challenges

Solar insecticidal lamps(SIL) can effectively control pests and reduce the use of pesticides. Combining SIL and Internet of Things(IoT) has formed a new type of agricultural IoT,known as SIL-IoT, which can improve the effectiveness of migratory phototropic pest control. However, since the SIL is connected to the Internet, it is vulnerable to various security issues.These issues can lead to serious consequences, such as tampering with the parameters of SIL, illegally starting and stopping SIL,etc. In this paper, we describe the overall security requirements of SIL-IoT and present an extensive survey of security and privacy solutions for SIL-IoT. We investigate the background and logical architecture of SIL-IoT, discuss SIL-IoT security scenarios, and analyze potential attacks. Starting from the security requirements of SIL-IoT we divide them into six categories, namely privacy, authentication, confidentiality, access control, availability,and integrity. Next, we describe the SIL-IoT privacy and security solutions, as well as the blockchain-based solutions. Based on the current survey, we finally discuss the challenges and future research directions of SIL-IoT.

Evaluation of the Insecticidal Effects of Aqueous Extracts of the Leaves of:Erythrophleum guineense and Uvaria chamae against Caryedon serratus Ol.(Coleoptera,Bruchidae),an Insect Pest of Groundnut Grains in the Republic of Guinea

The aim of this study is to evaluate the insecticidal potential of aqueous extracts of the leaves of Erythrophleum guineense and Uvaria chamae on Caryedon serratus Ol.(Coleoptera,Bruchidae),an insect pest of groundnut grains in the Republic of Guinea.To do this,tests on their insecticidal efficacy were carried out separately on groups of 8 bruchids using concentrations of aqueous extracts from their leaves in jars each containing 20 g of groundnut.The mortality of the bruchids and the impact of their aqueous extracts were observed and recorded for 96 h and 120 days after infestation,followed by a test of the germinative power of the seeds.Concentrations(C1)of aqueous extracts of the leaves of Erythrophleum guineense and Uvaria chamae applied to 20 g of groundnut resulted in bruchid mortality of 86.99%and 78.82%of each plant respectively.At the same doses,the treated seeds were not attacked during 4 months’storage.The germination rate of groundnut seeds at the start and end of the experiment was 97.65%and 93.60%respectively.Thus,aqueous extracts of the leaves of Erythrophleum guineense and Uvaria chamae can be considered as an alternative bio-insecticide against pests in groundnut storage shops.

Preparation of Amide-Containing Insecticidal Derivatives from the Renewable Natural Productβ-Pinene

The preparation of bioactive derivatives from the renewable natural product pinene is a hot research topic in the deep processing and utilization of pinene.In this study,β-pinene was used to develop novel molecules as a promising new precursor of insecticide.A series of amide-containing derivatives ofβ-pinene were synthesized and characterized.The insecticidal activities of these derivatives against Mythimna separate and Semiaphis heraclei were tested.The structure characterization results showed that the characterization data of amide-containing derivatives were in full agreement with their proposed structures.The insecticidal activities evaluation results indicated that amide-containing derivatives exhibited weak insecticidal activity against Mythimna separate,but exhibited moderate to good insecticidal activity against Semiaphis heraclei.After testing for 72 h,the corrected mortality against Semiaphis heraclei of compounds 5c,5e,5f,5 h,5j,and 5 m was 100%at 1000 mg/L.The structure-activity relationship analysis results showed that the introduction of an amide group into the structure of derivatives improved their insecticidal activity against Semiaphis heraclei.Meanwhile,the amide-containing derivatives containing the F and NO_(2) substituted benzene ring might improve their insecticidal activity against Semiaphis heraclei.This study will be helpful for the high value-added utilization of the natural renewable resourceβ-pinene and the development of novel insecticides.

Chemical Composition of Different Extracts of Conyza bonariensis: Insecticidal and Nematicidal Activities

C. bonariensis (L.) Cronq. known as hairy fleabane was first described in Argentina but it is now widely spread through most warmer regions of Europe, Africa, Asia, the Caribbean and Central America. In this work, a chemical analysis by liquid and gas chromatography coupled with mass spectrometry of the whole plant, aerial part, flowers and roots extracts of C. bonariensis harvested in Togo (West Africa) was carried out. Two acetylenic compounds Lachnophyllum ester and limonene were identified as the main components of essential oils while Lachnophyllum and Matricaria lactones were dominant in chloroform extracts. Based on the plant chemical compositions, essential oils and chloroform extracts were tested on cowpea weevil Callosobruchus maculatus adults which are considered as one of the most cosmopolitan pests of stored beans, and on freshly hatched second-stage juveniles of root-knot nematode Meloidogyne incognita. Results showed that the whole plant essential oil demonstrated an LC50/24h value of 1.75 μL oil/L air on C. maculatus while at 3.91 μL oil/L air, it showed 100% mortality. Furthermore, the plant root chloroform extracts partitioned in diethyl ether-hexane mixture showed the strongest nematicidal activity with an LC50/72h value of 0.47 mg/mL. Our findings suggest that the widely diffused plant C. bonariensis and its acetylenic constituents could be considered as potent botanical insecticidal and nematicidal agents.

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.

Insecticidal Activity and Physicochemical Characterization of Nanoparticles from Foliar Extract of Capsicum chinense

This work was carried out to evaluate the insecticidal effect of mono,bi and trimetallic nanoparticles(NPs)from leaf extract of habanero pepper(Capsicum chinense Jacq.)on the red flour beetle(Tribolium castaneum herbst.)and cotton mealybug(Phenacoccus solenopsis Tinsley).The results showed that Cu NPs,Cu/Mn NPs and Zn/Cu NPs had high insecticidal effect against T.castaneum(63%-80% mortality after 96 h).The Cu NPs and Zn/Cu NPs showed also insecticidal effect against P.solenopsis,but to a lesser extent(20%–28% after 96 h).With regards to the physicochemical characterization,Cu NPs had a zeta potential of 21.1 mV,whereas Cu/Mn NPs and Zn/Cu NPs exhibited zeta potentials of 200 mV.The polydispersity index(PDI)values for Cu NPs,Cu/Mn NPs,and Zn/Cu NPs were 10.1,29.16,and 14.34,respectively.The TF-IR spectra of the NPs varied from 600 to 4000 cm−1.The EDX weight percentages showed the presence of Cu(0.29%–2.4%),Mn(1.4%),and Zn(2.6%)in Cu/Mn NPs and Zn/Cu NPs,respectively.

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.

Insecticidal Activities of Extracts from Brucea javanica (L.) Merr. Callus

[Objective] The research aimed to lay a foundation for the screening of cell lines producing secondary metabolites of Brucea javanica(L.)Merr.[Method] The insecticidal activities of the extracts from branch and 3 different types of calluses of Brucea javanica(L.)Merr.was detected through methods of leaf disc and potted seedlings against the diamond back moth.[Result] Extracts from four kinds of Brucea javanica(L.)Merr.tissues assumed both the activities of antifeedant and oviposition deterrency against the diamond back moth.Antifeedant effect of extracts was in turn the callus C< callus B< callus A< branches.Oviposition deterrency activity of the extracts was in turn the callus A> branch > callus B>callus C.The insecticidal activities of callus A and B were higher than that of the callus C.[Conclusion] The results show that insecticidal activity of callus and its growth rate is inversely proportional.

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.

Insecticidal Activities of Alkaloids Extracted from Poisonous Plants

[Objective] Insecticidal activities of alkaloids extracted from 12 poisonous plants in Changbai Mountain were studied in the paper,to provide the basis for development and utilization of poisonous plants in Changbai Mountain.[Method] Leaf disc method was used to study the effects of alkaloids extracted from 12 poisonous plants on the growth and development of 3-5 instars of cabbage worm （Pieris rapae） and their antifeedant activities.[Result] The effects of alkaloids extracted from different poisonous plants on the growth and development of cabbage worm were also different.Five treatments of alkaloids extracted from Sophora flavescens,Datura stramonium L.,Arisaema amurense Maxim.,Veratum dahuricum Loes.and Tripterygium regelii Spragne et Takeda made the weight of test insects gradually decrease and finally die;the alkaloid treatments of Pueraria lobata （Willd.） Ohwi,Aconitum kusnezoffii Reichb.,Cimicifuga dahurica （Turcz.） Maxim.and Corydalis ambigua Schleeht.could make cabbage worm pupate ahead of time,but the pupa state was deformed;the antifeedant rates of cabbage worm after the treatments of P.lobata,A.kusnezoffii,C.dahurica,A.amurense,V.dahuricum and C.ambigua for 48 h were all over 90%,and the antifeedant rates of C.dahurica and C.ambigua were the highest as 100%.[Conclusion]The reports on the insecticidal activities of five poisonous plants including P.lobata,A.kusnezoffii,C.dahurica,C.ambigua and A.amurense are rare,and they have important values on the development of botanical pesticides.

Agrobacterium tumefaciens-mediated transformation of rice with the spider insecticidal gene conferring resistance to leaffolder and striped stem borer

Immature embryos of rice varieties "Xiushui11" and "Chunjiang 11" precultured for 4d were infected and transformed by Agrobacterium tumefaciens strain EHA101/pExT7 (containing the spider insecticidal gene). The resistant cant were transferred onto the differentiation medium and plants were regenerated. The transformation frequency reached 56%-72% measured as numbers of Geneticin (G418)-resistant calli produced and 36%-60% measured as numbers of transgenic plants regenerated, respectively. PCR and Southern blot analysis of transgenic plants confirmed that the T-DNA had been integrated into the rice genome. Insect bioassays using T1 transgenic plants indicated that the mortality of the leaffolder (Cnaphalocrasis medinalis) after 7d of leaf feeding reached 38%-61% and the corrected mortality of the striped stem borer (Chilo suppressalis) after 7d of leaf feeding reached 16%-75%. The insect bioassay results demonstrated that the transgenic plants expressing the spider insecticidal protein conferred enhanced resistance to these pests.

Insecticidal activities and active components of the alcohol extract from green peel of Juglans mandshurica

The extract of green peel of Juglans mandshurica Maxim was extracted by common method for studying its insecticidal activities and analyzing the active components. Results showed that the alcohol extract and the chloroform part of extract （separated with chloroform from alcohol extract） form green peel of J. mandshurica have insecticidal activities in contact toxicity and stomach toxicity against larvae of Lymantria dispar L.. After application of the extracts for five days, the corrected mortality of larvae of Lymantria dispar for both extracts was more than 50% in contact toxicity and stomach toxicity at the concentration of ≥ 5 g·L^-1. The insecticidal activity for both alcohol extract and chloroform part of extract is more effect in contact toxicity than in stomach toxicity, but no significant difference in the insecticidal activities was found between alcohol extract and chloroform part of extract. The active components in the chloroform part of extract from green peel of.J. mandshurica were analyzed by GC-MS. The analyzed results showed that the active components in the chloroform part of extract are： （1） joglone （5-hydroxy-1,4- naphthaoquinone）, the relative content 27.11%, （2） 1,5-Naphthalenediol, the relative content 9.52%, （3） 7-Methoxy-1-tetralone, the relative content 6.81%, （4） Benzofuran, 2,3-dihydro-, the relative content 6.76%, （5） 4-Hydroxy-2-methoxycinnamaldehyde, the relative content 3.99%, （6） 2-Methoxy-4-vinylphenol, the relative content 3.05%.

Antifungal,Insecticidal and Herbicidal Properties of Volatile Components from Paenibacillus polymyxa Strain BMP-11

The volatiles produced by Paenibacillus polymyxa strain BMP-11 which was isolated from the rhizosphere soil of cucumber in a greenhouse were analyzed by SPME-GC-MS.Based on the preliminary test,three kinds of purchased commercial products 1-octen-3-ol,benzothiazole and citronellol were chosen to give further assessment of their bioactivity.Antifungal bioassays in sealed dishes revealed that those three compounds strongly inhibited the mycelia growth of the eight pathogens at a low treatment dosage and induced the mycelial morphological abnormalities.During the experiment,we even found that citronellol completely prevented the pigment production of the tested fungus,Fusarium oxysporum,however,1-octen-3-ol and benzothiazole had slight effect.The germination was inhibited to different degrees when spores of Botrytis cinerea exposed to these compounds for 24 h in water agar plate.Furthermore,fumigation results showed that 1-octen-3-ol and benzothiazole had strong toxicity against Tribolium castaneum,LC50 was 16.76 and 3.50 mg L-1,respectively.The fumigation activity was also found similar to the positive control,1,3-dichloropropene （LC50 =10.13 mg L-1）.Results of herbicidal assays showed that tested compounds had inhibitory effects on the seed germination and seedling growth of Amaranthus retroflexus,Echinochloa crusgalli and Chenopodium album.Findings of the present study suggested that the antifungal,insecticidal and herbicidal properties of the components were contained in volatiles.These agents or even their derivatives may have a potential to be used as fungicide,insecticide as well as herbicide.

Comparison of Constituents and Insecticidal Activities of Essential Oil from Artemisia lavandulaefolia by Steam Distillation and Supercritical-CO_2 Fluid Extraction

Essential oil was extracted from Artemisia lavandulaefolia DC.by steam distillation（SD） and supercritical-CO2 fluid extraction（SFE）,respectively.The constituents of the essentil oils extracted with those two methods were analyzed by gas chromatography-mass spectrometry（GC-MS） and insecticidal activities of the essential oils were evaluated,then the results were compared to assess their biological activity.Thirty-one compounds were identified in the essential oil extracted by SD,and its main components were eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol and so on.Twenty-two compounds were identified for the essential oil extracted by SFE,and its main components were cyclodecene,n-hexadecanoic acid and so on.Six chemical compositions were all contained in the essential oils extracted by the two methods,i.e.,eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol,caryophyllene,[3aS-（3aα,3bβ,4β,7α,7aS）]-octahydro-7-methyl-3-methylene-4-（1-methylethyl）-1H-cyclopenta[1,3]cyclopropa-[1,2]benzene,nerolidol and（-）-Spathulenol.The fumigation toxicity of the essential oil obtained by means of SD to the adults of Sitophilus zeamais is significantly higher than that of the essential oil by means of SFE.The contact toxicity of the essential oil obtained by means of SFE to the adults of S.zeamais is higher than that of the essential oil obtained by means of SD,but the difference is not significant.

Relationship Between Leaf C/N Ratio and Insecticidal Protein Expression in Bt Cotton as Affected by High Temperature and N Rate

Expression of insecticidal protein for transgenic Bacillus thuringiensis （Bt） cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbon nitrogen ratio （C/N） and insecticidal efficacy of two Bt cotton cultivars. C/N ratio and Bt protein content were both measured at peak square period and peak boll period respectively under 5-7 d high temperature and different nitrogen fertilizer rates on the Yangzhou University Farm and the Ludong Cotton Farm, China. All plants were grown in field. The results showed that the C/N ratio enhanced slightly and the Bt protein content remained stable at peak square period, but significant increases for the C/N ratio and decreases markedly for the leaf Bt protein concentration were detected at the peak boll period. The similar patterns at the two growth periods were found for the leaf C/N ratio and Bt protein content by different N fertilizer treatments. When nitrogen rate was from 0 to 600 kg ha-l, the C/N ratio was reduced by 0.017 and 0.006 for Sikang 1 and Sikang 3 at peak square period, compared to the 1.350 to 1.143 reduction for Sikang 1 and Sikang 3 at peak boll period, respectively. Correspondingly, the leaf Bt protein contents were bolstered by 2.6-11.8 and 26.9-36.9% at the two different growth periods, respectively. The results suggested that enhanced C/N ratio by high temperature and nitrogen application may result in the reduction of inseetiocidal efficacy in Bt cotton, especially in peak boll period.

Insecticidal,antimicrobial and antioxidant activities of bulb extracts of Allium sativum

Objective:To evaluate the insecticidal,antimicrobial and antioxidant activities of bulb extracts of Allium sativum(A.sativum).Methods:Dried bulbs of A.sativum were extracted with different solvents and evaluated for insecticidal,antimicrobial and antioxidant activities.Results: Aqueous and methanol extracts showed highest insecticidal activity(mortality rate of 81%and 64%respectively) against the larvae of Spodoptera litura(S.litura) at a concentration of 1000 ppm.With regard to antimicrobial activity,aqueous extract exhibited antibacterial activity against gram positive(Bacillus subtilis,Staphylococcus aureu,) and gram negative(Escherichia coli and Klebsiella pneumonia) strains and antifungal activity against Candida albicans.While methanol extract showed antimicrobial activity against all the tested micro organisms except two(Staphylococcus aureus and Candida albicans),the extracts of hexane,chloroform and ethyl acetate did not show any anti microbial activity.Minimum inhibitory concentration of aqueous and methanol extracts against tested bacterial and fungal strains was 100-150μg/mL. Antioxidant activity of the bulb extracts was evaluated in terms of inhibition of free radicals by 2.2’-diphenly-l-picrylhydrazyl.Aqueous and methanol extracts exhibited strong antioxidant activity(80%-90%of the standard).Conclusions:Antioxidant and antimicrobial activity of A.sativum against the tested organisms therefore,provides scientific basis for its utilization in traditional and folk medicine.Also,our results demonstrated the insecticidal efficacy of A. sativum against S.litura,a polyphagous insect.

Reduced square Bacillus thuringiensis insecticidal protein content of transgenic cotton under N deficit

To clarify the effect of the N deficit on the amount of square Bt insecticidal protein, different N application rates(0, 75, 150, 225, and 300 kg ha^–1) were imposed on the conventional cultivar Sikang 1(SK-1) and hybrid cultivar Sikang 3(SK-3) during 2015–2016 cotton growth seasons. Under different N application rates, the square number per plant, square volume and square dry weight reduced when the N rates decreased from conventional rate(300 kg ha^–1) to 0 kg ha^–1. And the square Bt protein content decreased accordingly. The analysis of N metabolism showed that soluble protein content, GPT and GOT activities decreased, free amino acid, peptidase and protease activities increased under N deficit. Correlation analysis indicated that the reduced Bt protein content under N deficit was related to altered N metabolism. In conclusion, square development and the amount of square Bt toxin both decreased under N deficit, indicating that promoting the square development under appropriate N application rate would also promote the insect resistance during squaring stage.

Synthesis of insecticidal sucrose esters

Some synthetic sucrose esters （SE） are a relatively new class of insecticidal compounds produced by reacting sugars with fatty acids, which are safe for the environment. Especially, sucrose esters composed of C6-C12 fatty acids have desirable insecticidal properties against many soft-bodied arthropod pests. In our study, sucrose octanoate which has the highest activity against a range of arthropod species was synthesized by a trans-esterification method and proved its insecticidal property. Under the condition of a homogeneous liquid, sucrose octanoate was prepared by reacting ethyl octanoate with sucrose at reduced pressure; the yield was 79.11%. Sucrose octanoate synthesized was identified and its property analyzed by IR, TLC and spectrophotometric analysis. It was shown that the ratio of monoester to polyester in sucrose octanoate was 1.48：1. The insecticidal activity of the synthetic sucrose octanoate was evaluated at a concentration of 4 and 8 mg.mL^-1. The mortality of first-instar larvae ofLymantria dispar from its contact toxicity was 72.5% after 36 hours, the revision insect reduced rate of Aphis glycines reached above 80% at 4 and 8 mg.mL^-1 after being treated for 5 days. Since the SE products are nontoxic to humans and higher animals, fully biodegradable and hydrolyzed to readily metabolizable sucrose and fatty acid, they are not harmful to crops and appear to be good insecticide candidates.

Insecticidal Constructure and Bioactivities of Compounds from Ficus sarmentosa var.henryi

Insecticidal activities of the petroleum ether-, chloroform-, ethyl acetate-, and water-soluble fractions of the methanolic extract ofFicus sarmentosa var. henryi were assayed against Musca domestica adults. The chloroform- and ethyl acetate- soluble fractions were the most active with 92.6 and 88.9% mortalities （24 h after treatment） respectively. Therefore, the two fractions were combined and four compounds, isolated from the fractions by activity-guided fractionation, were elucidated as 7-hydroxycoumarin, apigenin, eriodictyol, and quercetin by spectroscopic method and displayed excellent insecticidal activities against adults of M. domestica and 4th instar larva of Aedes albopictus. Among those, 7- hydroxycoumarin showed the strongest insecticidal activities with lethal concentrations （LC50） values of 72.13 μg g^-1 sugar and 4.87 μg mL^-1 （48 h after treatment） against the test insects respectively. The cytoxicities of these compounds on BTI-Tn-5B 1-4 cell were also investigated for the insecticidal mechanism and found that quercetin represented superior inhibitory activity with MTT assay and reactive oxygen species （ROS） against BTI-Tn-5B 1-4 cell, but slightly weaker than that of the positive control （azadirachtin） and significantly greater than the negative control （DMSO only）. Meanwhile, eriodictyol demonstrated the strongest effect on the mitochondrial membrane potentials （MMP）. In conclusion, based on their comparative toxicities to commercial insecticides and their cytotoxic effects, some of the compounds from the F. sarmentosa have potential as botanical insecticides.

Impacts of Environmental Factors on Degradation of CrylAb Insecticidal Protein in Leaf-Blade Powders of Transgenic Bt Rice

The determination of the environmental fate of Bt insecticidal protein released by Bt rice plants in paddy soils is a key issue in its ecological risk assessment. In this study, the impacts of soil water content, pH, and temperature on the degradation of CrylAb protein expressed in the leaves of Bt rice KMD2 were studied in the laboratory. Three types of paddy soils were used, i.e., blue clayey paddy soil, pale paddy soil on quaternary red soil, and marine-fluvigenic yellow loamy paddy soil. Ground powders of KMD2 leaf blades were mixed with each type of soil, and degradation dynamics of Cry lAb were measured using enzyme-linked immunosorbent assay （ELISA）. The degradation rate of CrylAb was high at the early experimental stage, but slowed down steadily at middle and later stages, which could be described by exponential equations, with the half-life period of degradation determined as 1.8-4.0 d. The soil water content, pH, and temperature could affect the degradation of CrylAb, but the effects of soil pH and temperature were relatively greater. In general, CrylAb degradations were slower under lower soil pH and temperature conditions, especially for marine-fluvigenic yellow loamy paddy soil.