The effects of citrus varieties on the population of citrus leaf miner (CLM) Phyllocnistis citrella Staiton (Lepidoptera: Phyllocnistidae) were studied based on the indoors experiments. The results showed that there were significant... more
The effects of citrus varieties on the population of citrus leaf miner (CLM) Phyllocnistis citrella Staiton (Lepidoptera: Phyllocnistidae) were studied based on the indoors experiments. The results showed that there were significant differences in developmental duration of immature stage from eggs to pupae, survival of larvae, emergency ratio of pupae, fertility and longevity of female adults and life table parameters among the tested varieties. For the CLM on Citrus tangerina Hort.ex Tannaka, compared with that on the other 3 tested varieties ( C.s sinesis Osbeck, C.tangerina Blanco and C.tankan Hayata), the developmental duration (19.58 d) was the longest; the fertility (20.91 individuals per female) was the lowest; longevity of female adult (6.96 d) was the shortest. The intrinsic rate for population increase ( r m =0.0721) and infinite rate of increase (λ=1.075 d -1 )were the least, the mean length of generation (T=21.5 d) was the longest. Consequently, C.tangerina Hort.ex Tanna...
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Entomopathogenic fungi are proposed biological control agents against the Asian citrus psyllid (Diaphorina citri). We quantified the pathogenicity of Cordyceps javanica strain Apopka 97 strain (Cja Apopka 97) (blastospores and conidia)... more
Entomopathogenic fungi are proposed biological control agents against the Asian citrus psyllid (Diaphorina citri). We quantified the pathogenicity of Cordyceps javanica strain Apopka 97 strain (Cja Apopka 97) (blastospores and conidia) against D. citri using the spray technique. We also used light and scanning electron microscopy to observe the Cja Apopka 97, infection process against D. citri adults at different stages pre- and post-mortem. Our findings demonstrated that psyllid mortality in the blastospore treatment ranged from 8 to 25% within 24–48 h of exposure, compared to 0% in the conidial and control treatments. However, psyllid mortality rate had reached 100% by 7 days after exposure at a concentration of 107 spores/mL, under both fungal treatments compared to the controls (0%). SEM and light microscopy revealed several stages in in the Cja Apopka 97 infection process of D. citri, including spore adherence and germ tube formation within 24 h post-inoculation, penetration pe...
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The current study was conducted to assess the impact of powdery mildew (Oidium neolycopersici) on plant-non-vector herbivore-parasitoid interactions, e.g. tomato plants, whiteflies (Trialeurodes vaporariorum) and parasitoid (Encarsia... more
The current study was conducted to assess the impact of powdery mildew (Oidium neolycopersici) on plant-non-vector herbivore-parasitoid interactions, e.g. tomato plants, whiteflies (Trialeurodes vaporariorum) and parasitoid (Encarsia formosa). Encarsia females were significantly less attracted to powdery mildew infected tomato plants (PM) than healthy plants (Con.). Thus parasitism rates of whiteflies (WF) were significantly lower on powdery mildew (PM) plants as compared to Con. plants (17.5:41.5%). These differences disappeared when E. formosa females were forced to parasitize whiteflies on either PM or Con. The performance of the parasitoid was not significantly influenced when developing on whiteflies feeding on powdery mildew infected plants. In olfactometer bioassays, either naïve or experienced parasitoids significantly preferred healthy plants colonised by whiteflies as compared to powdery mildew infected plants colonised by whitefly (PMWF) (30.0:10.0% for naïve parasitoids; 41.4:15.2% for experienced parasitoids). In wind tunnel bioassays, volatiles emitting from WFs significantly increased upwind oriented flight and landing in Encarsia targets as compared to any other treatments. Volatiles from Con, PM, PMWF and WF were collected and analyzed by GC and GC-MS, revealing that both qualities and quantities of volatile compounds differed to a large extend. Plants significantly increased volatile emission after being attacked by whiteflies (275.3 mol h−1) or infected by powdery mildew (267.58 mol h−1). However, plants significantly reduced volatile emissions in PMWF co-existing systems (80.58 mol h−1). Our results demonstrate that volatiles released by either herbivore damaged plants, pathogen diseased plants or combinations of these agents, respectively, may influence the foraging behavior of the parasitoids while searching for their hosts, resulting in reduced efficacies of parasitoids. This, in turn, may impact the outcome of biological control systems, especially in greenhouse conditions.
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Diaphorina citri is a serious insect pest of citrus and an insect vector of Candidatus Liberibacter asiaticus (CLas) that causes Huanglongbing disease (citrus greening). In this study, we investigated the effect of the CLas pathogen on... more
Diaphorina citri is a serious insect pest of citrus and an insect vector of Candidatus Liberibacter asiaticus (CLas) that causes Huanglongbing disease (citrus greening). In this study, we investigated the effect of the CLas pathogen on the life history parameters of D. citri at different temperature regimes. Our results demonstrated that the survival rate of first to fifth instar CLas-positive and CLas-negative D. citri fluctuate with the change in temperature over the range of 16–35 °C. Meanwhile, the mean developmental time (52.5 d) (d = day(s)) and adult longevity (5.2 d) of the CLas-positive psyllids was longer as compared to CLas-negative psyllids mean developmental time (32.81 d) and adult longevity (3.50 d) at the low- and high-temperature regimes (16 and 35 °C). However, at high temperature regimes, the significant effect of CLas-bacteria on D. citri fecundity was higher than the corresponding non-significant effect on their survivorship when compared to non-vectored psyllid...
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In response to mitigating the negative impacts of synthetic insecticides in controlling Diaphorina citri, the main vector of Huanglongbing, we assessed the effects of endophytically colonized Citrus limon seedlings by Beauveria bassiana... more
In response to mitigating the negative impacts of synthetic insecticides in controlling Diaphorina citri, the main vector of Huanglongbing, we assessed the effects of endophytically colonized Citrus limon seedlings by Beauveria bassiana BB‐16 on the population fitness of D. citri using the age‐stage two‐sex life‐table theory. The mean fecundity (F) and reproductive rate (R0) of the F1 generation of D. citri reared on endophytically colonized plants (F = 121.7; R0 = 30.43) were significantly lower than the endophyte‐free plants (F = 438; R0 = 197.1). In addition, the values of finite rate of increase (λ) and intrinsic rate of increase (r) on endophytically colonized plants (λ = 1.0927 day−1; r = 0.0887 day−1), were significantly lower than the endophytes free plants (λ = 1.1528 day−1; r = 0.1422 day−1). Moreover, the pre‐adult survival rate (sa) on endophytically colonized plants (sa = 37.5%) was significantly lower than the endophyte‐free plants (sa = 75%). Our results demonstrate that B. bassiana BB‐16 established as endophyte in C. limon under controlled conditions, reduced the population fitness of D. citri progeny and highlight the potential of integrating this entomopathogenic fungus as endophyte for sustainable management of D. citri and other citrus pests in citrus orchards.
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SummaryMicrobiome analysis in a host–parasitoid interaction network was conducted to compare the taxonomic composition of bacterial communities ofDiaphornia citri,Tamarixia radiata, andDiaphorencyrtus aligarhensis. The comparative... more
SummaryMicrobiome analysis in a host–parasitoid interaction network was conducted to compare the taxonomic composition of bacterial communities ofDiaphornia citri,Tamarixia radiata, andDiaphorencyrtus aligarhensis. The comparative analysis revealed differences in the composition and diversity of the symbiont populations across the host and its associated parasitoids. Proteobacteria was the most dominant phylum, representing 67.80% of the total bacterial community, whileCandidatusProfftella armature andWolbachiawere the dominant genera across the host and parasitoids. There were clear differences observed in alpha and beta diversity of microbiota through the host and its associated parasitoids. The function prediction of bacterial communities and Pearson correlation analysis showed that specific bacterial communities displayed positive correlations with the carbohydrate metabolism pathway. Furthermore, when symbiotic bacteria were eliminated using a broad‐spectrum antibiotic, tetracy...
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These studies were conducted to find out the efficacy of different release methods of Trichogramma chilonis (Ishii) in different sugarcane varieties for the management of sugarcane stem borer, Chilo infuscatellus (Snell) in sugarcane... more
These studies were conducted to find out the efficacy of different release methods of Trichogramma chilonis (Ishii) in different sugarcane varieties for the management of sugarcane stem borer, Chilo infuscatellus (Snell) in sugarcane plant crop. The results showed that the infestation of C. infuscatellus in different sugarcane varieties started in April and continued till the end of the October. Significantly lowest percent infestation of C. infuscatellus (1.76%) was recorded in variety CP-77/400 followed by SPSG-79 (2.80%). While significantly highest percent infestation (3.36%) of C. infuscatellus was recorded in variety Mardan-92. The data also showed significant differences in the different release methods of T. chilonis. Significantly lowest percent infestation (1.74%) of C. infuscatellus was recorded in different plots treated with inundative release method followed by plots treated with inoculative release method, where 2.68% infestation of C. infuscatellus was recorded. Maxi...
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Termitesare very devastating insect pests of agricultural, ornamental crops and dry wood.They are social insect having strong inter-communication, due to which they are very active pests,withboth positive and negative effects on the... more
Termitesare very devastating insect pests of agricultural, ornamental crops and dry wood.They are social insect having strong inter-communication, due to which they are very active pests,withboth positive and negative effects on the environment. They are found in every type of soil in the world,and have a broad range of species. Management of termites has been approached with a number of different stretigies, especially chemical pesticides, which have otherenvironmental site impacts. Microbial biological control is defined as the use, and proper adjustment, of natural enemies via microbial organisms, such as; fungi, virus, bacteria, and with the aim of suppression and management of insect populations. A broad range of species, from different groups of microbial organisms, have strong association with termites, and some have been recorded as parasites. Somespecies are currently used as commercial biological control agents of termites.
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Sulfoxaflor belongs to a new class of insecticides which are effective against many sap-feeding pests. Sitobion miscanthi, Rhopalosiphum padi, and Metopolophium dirhodum are the predominant pests coexisting on wheat plants. It is unknown... more
Sulfoxaflor belongs to a new class of insecticides which are effective against many sap-feeding pests. Sitobion miscanthi, Rhopalosiphum padi, and Metopolophium dirhodum are the predominant pests coexisting on wheat plants. It is unknown whether these aphid species have developed resistance to sulfoxaflor. Here, the susceptibilities of three wheat aphid species from different regions of China to sulfoxaflor were evaluated. The results showed that two S. miscanthi, one R. padi, and two M. dirhodum field populations were highly resistant to sulfoxaflor. Additionally, 13 S. miscanthi, 9 R. padi, and 4 M. dirhodum field populations were moderately resistant to sulfoxaflor. Analysis of differences in toxicity showed that the susceptibility levels of R. padi in 9 of 20 regions, M. dirhodum in 5 of 9 regions, and M. dirhodum in 3 of 9 regions to sulfoxaflor were greater than those of S. miscanthi, S. miscanthi, and R. padi in the same regions, respectively. Thus, each wheat aphid species h...
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Temperature is a key parameter that affects insect population, abundance, and distribution in tropical and subtropical regions. Tamarixia radiata Waterson (Hymenoptera: Eulophidae) is a species-specific ectoparasitoid widely used as a... more
Temperature is a key parameter that affects insect population, abundance, and distribution in tropical and subtropical regions. Tamarixia radiata Waterson (Hymenoptera: Eulophidae) is a species-specific ectoparasitoid widely used as a biological control agent for the major citrus pest Diphornia citri Kuwayama (Hemiptera: Liviidea). To date, T. radiata response to high temperature at the molecular level still is unclear. In this study, we conducted a comparative analysis of the transcriptomes of T. radiata exposed at 25 °C and 38 °C for 15 min. A total of 51,072 unigenes were obtained, 22,413 annotated with a mean length of 1054 bp. Differential expression analysis showed that 502 genes were identified, including 476 genes significantly up-regulated and 26 genes down-regulated after heat stress exposure. The Gene Ontology analysis showed that most enriched DEGs are categorized into "cellular process", "metabolic process" and "DNA binding." In addition, "Lysosome," "Longevity regulating pathway-multiple species," and "starch and sucrose metabolism" were highly enriched in Kyoto Encyclopedia of Genes and Genomes pathways. Transcriptome analyses showed that heat stress significantly induced the transcription of the molecular chaperone, immune response, stress signaling transduction, and oxidation resistance, including highly expressed heat shock proteins, ATPases, and detoxifying enzymes. Furthermore, the expression patterns of thirteen genes including heat shock proteins (HSP), glutathione S-transferase (GST) and cytochrome P450 were consistent with the transcriptome results obtained through qRT-PCR. Together, our results provided a comprehensive study of the molecular response of T. radiata to heat stress and provides new insight for the future functional validation of heat resistance-related genes.
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The host-pathogen interaction has been explored by several investigations, but the impact of fungal pathogens against insect resistance is still ambiguous. Therefore, we assessed the enzymatic activity and defense-related gene expression... more
The host-pathogen interaction has been explored by several investigations, but the impact of fungal pathogens against insect resistance is still ambiguous. Therefore, we assessed the enzymatic activity and defense-related gene expression of Asian citrus psyllid (ACP) nymphal and adult populations on Huanglongbing-diseased citrus plants under the attack of Cordyceps fumosorosea. Overall, five enzymes viz. superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione S-transferase (GST), carboxylesterase (CarE), and four genes, namely SOD, 16S, CYP4C68, CYP4BD1, were selected for respective observations from ACP populations. Enzymatic activity of four enzymes (SOD, POD, GST, CarE) was significantly decreased after 5-days post-treatment (dpt) and 3-dpt fungal exposure in fungal treated ACP adult and nymphal populations, respectively, whereas the activity of CAT was boosted substantially post-treatment time schedule. Besides, we recorded drastic fluctuations in the expression of CYP4 genes among fungal treated ACP populations. After 24 hours post-treatment (hpt), expression of both CYP4 genes was boosted in fungal treated populations than controlled populations (adult and nymph). After 3-dpt, however, the expression of CYP4 genes was declined in the given populations. Likewise, fungal attack deteriorated the resistance of adult and nymphal of ACP population, as SOD expression was down-regulated in fungal-treated adult and nymphs after 5-dpt and 3-dpt exposure, respectively. Moreover, bacterial expression via the 16S gene was significantly increased in fungal-treated adult and nymphal ACP populations with increasing post-treatment time. Overall, our data illustrate that the fungal application disrupted the insect defense system. The expression of these genes and enzymes suppress the immune function of adult and nymphal ACP populations. As it is reported first time that the applications of C. fumosorosea against ACP reduce insect resistance by interfering with the CYP4 and SOD system. Therefore, we propose new strategies to discover the role of certain toxic compounds from fungus, which can reduce insect resistance, focusing on resistance-related genes and enzymes.
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The parasitism rate and host-feeding rate of Tamarixia radiata (Hymenoptera: Eulophidae), an ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae), were evaluated at 20, 27.5, 30, and 35°C, at 70 ± 5% RH, and 14 h of photoperiod. The... more
The parasitism rate and host-feeding rate of Tamarixia radiata (Hymenoptera: Eulophidae), an ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae), were evaluated at 20, 27.5, 30, and 35°C, at 70 ± 5% RH, and 14 h of photoperiod. The biological control efficacy of T. radiata was evaluated by linking the age-stage predation rate with the two-sex life table. The net host-feeding rate (C0) by T. radiata was 32.05, 54.40, 17.25, and 1.92 nymphs per female parasitoid at 20, 27.5, 30, and 35°C, respectively. The total net nymphs killing rate (Z0) was 103.02, 223.82, 72.95, and 6.60 nymphs per female parasitoid at 20, 27.5, 30, and 35°C, respectively. Noneffective parasitism rate was observed at 35°C because of high mortality at this temperature. Our results indicated that temperature had meaningful effects on parasitism and host-feeding rate parameters in the laboratory, and may affect biological control efficiency of the parasitoid in the field. The highest host-feeding rate and total...
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Some parasites have evolved the ability to adaptively manipulate host behavior. One notable example is the fungus Ophiocordyceps unilateralis sensu lato, which has evolved the ability to alter the behavior of ants in ways that enable... more
Some parasites have evolved the ability to adaptively manipulate host behavior. One notable example is the fungus Ophiocordyceps unilateralis sensu lato, which has evolved the ability to alter the behavior of ants in ways that enable fungal transmission and lifecycle completion. Because host mandibles are affected by the fungi, we focused on understanding changes in the metabolites of muscles during behavioral modification. We used High-Performance Liquid Chromatography-Mass/Mass (HPLC-MS/MS) to detect the metabolite difference between controls and O. unilateralis-infected ants. There was a significant difference between the global metabolome of O. unilateralis-infected ants and healthy ants, while there was no significant difference between the Beauveria bassiana treatment ants group compared to the healthy ants. A total of 31 and 16 of metabolites were putatively identified from comparisons of healthy ants with O. unilateralis-infected ants and comparisons of B. bassiana with O. u...
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Entomopathogenic fungi based microbial insecticides are considered as safe alternatives to chemical pesticides, which secretes several bioactive compounds to kill the host insects. In this study, we report a new approach for the synthesis... more
Entomopathogenic fungi based microbial insecticides are considered as safe alternatives to chemical pesticides, which secretes several bioactive compounds to kill the host insects. In this study, we report a new approach for the synthesis and characterization of insecticide toxic protein IF8 produced by the Isaria fumosorosea 08, and to evaluate the mycotoxin level against the vector of Huanglongbing (HLB) or citrus greening disease, the Asian citrus psyllid, Diaphorina citri. Soluble toxic metabolites extracted from I. fumosorosea 08 through submerged liquid state culture had a molecular weight of 43 kDa when subjected by to sodium dodecyl sulfate-poly-acrylamide (SDS-PAGE) gel electrophoresis. The most abundant of toxic protein IF8 was determined by High-performance liquid chromatography (HPLC) and liquid chromatography electrospray ionization-mass spectroscopy (LC-ESI-MS) for the analysis of its molecular mass weight and purity. Further Matrix-assisted laser desorption ionization...
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The development of resistance to chemical insecticides and concerns over the deleterious effects of chemicals on environmental and human safety have provided a strong impetus for the development of microbial control agents for use in... more
The development of resistance to chemical insecticides and concerns over the deleterious effects of chemicals on environmental and human safety have provided a strong impetus for the development of microbial control agents for use in integrated control of insect pests. A diverse assemblage of microorganisms is currently under consideration as control agents of insects, including viruses, bacteria, protozoans, and fungi. Fungi will not be cure-alls for pest problems on all crops and in all agricultural settings, and it is unlikely that they will ever totally supplant the management of insect pests with chemical insecticides. Nevertheless, they represent a valuable management resource to be utilized within an IPM framework and will contribute significantly to reductions in chemical pesticide use. However, the research, development and final commercialization of fungal biological control agents (BCAs) continue to confront a number of obstacles, ranging from elucidating important basic biological knowledge to socioeconomic factors. Currently, considerable advances have been made in the infection mechanism. In this chapter, we present the biocontrol of diamondback moth, Plutella xylostella with Beauveria bassiana and its metabolites, with an elucidation on the infection behavior of B. bassiana to P. xylostella and virulence of the fungal isolate and its metabolites. The fungi that have received the majority of attention for P. xylostella control are the Deuteromycetes because of their prevalence, possibility for production on artificial media, ease of application, and relatively long shelf lives.
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Crude toxins [toxinV3450 and toxinVp28, extracted from Lecanicillium (Verticillium) lecanii (Zimmermann) Gams & Zare strain V3450 and Vp28 respectively] were tested for contact toxicity, feeding deterrence and repellent activity against... more
Crude toxins [toxinV3450 and toxinVp28, extracted from Lecanicillium (Verticillium) lecanii (Zimmermann) Gams & Zare strain V3450 and Vp28 respectively] were tested for contact toxicity, feeding deterrence and repellent activity against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Both toxins showed ovicidal activity to eggs, with LC50 values of 447 and 629 mg L−1 respectively. Nymphs of B. tabaci were the most susceptible stages (LC50 values were calculated at 111 mg L−1 for toxinV3450 and 216 mg L−1 for toxinVp28), and adults were the second most susceptible stages (48 h LC50 values were calculated at 178 mg L−1 for toxinV3450 and 438 mg L−1 for toxinVp28). Applied to seedlings at a concentration of 400 mg L−1, the toxins significantly (P < 0.001) reduced the hatching of whitefly eggs and the subsequent survival rate of the nymphs, and the emergence and fecundity of the progeny adults. Both toxins exhibited repellent activity at low concentrat...
Research Interests: Reproduction, Biology, Medicine, Insecticides, Toxicity, and 15 moreMycotoxins, Animals, Feeding Behavior, Hemiptera, Insect repellents, Toxin, Homoptera, Nymph, Toxicity Tests, Whitefly, Pest Management Science, Plant Leaves, ENVIRONMENTAL SCIENCE AND MANAGEMENT, ipomoea batatas, and Complex Mixtures
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:Bioassays of six strains of Verticillium lecanii (Zimmermann) Viégas were conducted with the sweet potato whitefly, Bemisia tabaci. For inoculation, batches of third‐instar whitefly nymphs on sweetpotato seedlings were immersed in... more
:Bioassays of six strains of Verticillium lecanii (Zimmermann) Viégas were conducted with the sweet potato whitefly, Bemisia tabaci. For inoculation, batches of third‐instar whitefly nymphs on sweetpotato seedlings were immersed in conidial suspensions of five dosages at concentrations from 103 to 107 conidia/ml. Each dosage was used to inoculate 150–250 nymphs. The nymphs were maintained at 25°C, under 95% RH, photo phase of 16 : 8 (L : D) and observed daily for mortality. The resulting data were analysed over 8 days by a complementary log‐log (CLL) time‐dose‐mortality model, based on the Hosmer–Lemeshow test, analysing the time‐dose trends for five concentrations of six strains of V. lecanii simultaneously. The parameters from the model were used to estimate the virulence indices (the values of LC50) of six strains against B. tabaci. Based on the time‐dose‐mortality relationships fitted and the virulence indices, the virulence of the six strains of V. lecanii for B. tabai was compared. Results indicated that the strain Vl6063 imported from Canada and the domestic strains V3450 and Vp28 derived from B. tabaci and a scale insect, respectively, were more virulent than the others with LC50 values of 2.57 × 105, 6.03 × 105 and 6.03 × 105, respectively.
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Abstract: Population dynamics of the citrus leaf‐miner (CLM) Phyllocnistis citrella Stainton, and its major parasitoid Citrostichus phyllocnistoides (Narayanan) were investigated from June to September 1994 at the teaching and research... more
Abstract: Population dynamics of the citrus leaf‐miner (CLM) Phyllocnistis citrella Stainton, and its major parasitoid Citrostichus phyllocnistoides (Narayanan) were investigated from June to September 1994 at the teaching and research farm of the Fujian Agricultural and Forestry University (FAFU), south‐east China. Based on the field investigation, the functional and numerical responses of C. phyllocnistoides were studied in laboratory experiments. During the survey period, four peaks of CLM and C. phyllocnistoides populations were observed in the growing stage of summer shoots and two peaks of CLM and C. phyllocnistoides populations, respectively, in the growing stage of fall shoots. C. phyllocnistoides is the most abundant parasitoid both in seasonal and spatial dynamics, and demonstrates a Holling type III functional response to CLM. Parasitism varied with the densities of both parasitoid and host. A 1 : 10 ratio was recorded to be an optimal proportion of C. phyllocnistoides to CLM.
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The relationshLps between relative humidity (RH) and survival rates of eggs, all larval stages and pupae of the citrus leaf‐miner, Phyllooiistis citrella Stainton, were determined by laboratory experiments. The survival of the citrus... more
The relationshLps between relative humidity (RH) and survival rates of eggs, all larval stages and pupae of the citrus leaf‐miner, Phyllooiistis citrella Stainton, were determined by laboratory experiments. The survival of the citrus leaf‐miner was observed at seven levels of relative humidity from 35% RH to 95% RH at intervals of 10% RH, with 12 L: 12 D photoperiod and temperatiure (29±0.5) C. The relative humidity was controlled by saturated solutions of MgCl2 6H2O, K2CO3 2H2O, C6H12O6, NaNO2, NaCl, KCl, and Pb(NO3)2. The results showed that lower relative humidity is unfavorable for incubation of the eggs, survival of the larvae and eclosion of the pupae. The survival rates increased generally with rising of relative humidity within the range of 35% ‐ 85% RH, and the maximum survival rates occurred at 85% RH for different life stages. The variations in hatching rates of the eggs, survival rates of the larvae and emergence rates of the pupae were great, but unimodal at different r...
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Insect herbivores are dangerous to all stages of plants, e.g., vegetative as well as reproductive growth, leaves and shoots. Some of the herbivores feed by sucking plant sap, whereas some insects choose to chew various parts of plants.... more
Insect herbivores are dangerous to all stages of plants, e.g., vegetative as well as reproductive growth, leaves and shoots. Some of the herbivores feed by sucking plant sap, whereas some insects choose to chew various parts of plants. Thus, all types of herbivores damage the plant by feeding directly and cause multiple diseases to plants, leading to plant damage indirectly. However, due to insect attack, plants produce some bioactive compounds (which are known as saponins) to improve their defense mechanism against herbivores. These saponins are further divided into two main categories, e.g., steroidal saponins and terpenoidal saponins. Here, we have highlighted the importance of saponins from multiple plant families against various herbivores. Saponins are present in different wild plants as well as cultivated crops (e.g., soybeans, tea, spinach, oats, peppers, capsicum, quinoa, and alliums). Some of the saponins play a role as antifeedant, while some are insecticidal to different life stages of insect pests. Thus, these saponins play an important role in the plant defense against different insect pests. Moreover, different saponins are effective against stored grain pests as well as cosmopolitan insect pests. Therefore, these plant bioactive compounds could be helpful for integrated pest management in different ecosystems.
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Tamarixia radiata Waterson (Hymenoptera: Eulophidea) is the principal natural enemy used for the control of the major citrus pest Diaphorina citri Kuwayama (Hemiptera: Liviidae). In this study, we collected the life-history data of T.... more
Tamarixia radiata Waterson (Hymenoptera: Eulophidea) is the principal natural enemy used for the control of the major citrus pest Diaphorina citri Kuwayama (Hemiptera: Liviidae). In this study, we collected the life-history data of T. radiata at four different temperatures (20, 27.5, 30, and 35°C) and analyzed them by using the age-stage, two-sex life table. The longest preadult developmental time (16.53 d) was observed at 20°C, whereas the shortest one was 7.29 d at 35°C. The preadult development rate was well-fitted to a linear equation. The lower threshold temperature (T0) was 7.85°C and the thermal summation (K) was 193.36 degree-day. The highest fecundity (F) was 322.7 eggs per female was at 27.5°C, whereas the lowest one was 10.8 eggs per female at 35°C. The net reproductive rate (R0) were 70.97, 169.42, 55.70, and 3.25 offspring at 20, 27.5, 30, and 35°C, respectively; the intrinsic rate of increase (r) were 0.1401, 0.3167, 0.3517, and 0.1143 d−1, respectively. The highest va...
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The mechanism underlying the mediation of the behavior and fitness of non-vector herbivores by fungal pathogen-infected host plants is still unclear. In this study, we experimentally assessed the effects of tomato (Lycopersicon esculentum... more
The mechanism underlying the mediation of the behavior and fitness of non-vector herbivores by fungal pathogen-infected host plants is still unclear. In this study, we experimentally assessed the effects of tomato (Lycopersicon esculentum L.) plant infection status on non-vector herbivores using tomato powdery mildew disease fungus (Oidium lycopersici) and the greenhouse whitefly Trialeurodes vaporariorum as a model multitrophic plant-pathogen, non-vector herbivore interaction. In behavioral bioassays, powdery mildew-infected plants (PM) and plants damaged by combined attack of powdery mildew and whiteflies (PMWF) attracted significantly more whiteflies (32.6% and 58.1% for PM and PMWF, respectively) than control (Con) plants (16.5%) or plants damaged only by whiteflies (WF) (24.2%). Whiteflies feeding on PM or PMWF plants secreted almost twice as much honeydew as on the Con or WF plants. This indicated that whiteflies fed more on diseased plants than healthy plants. However, the pr...
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The effect of the entomopathogenic fungus Beauveria bassiana (BB-12) on the biological characteristics of Tamarixia radiata parasitizing Diaphorina citri was studied under laboratory conditions. Twenty 3rd–5th instar nymphs were exposed... more
The effect of the entomopathogenic fungus Beauveria bassiana (BB-12) on the biological characteristics of Tamarixia radiata parasitizing Diaphorina citri was studied under laboratory conditions. Twenty 3rd–5th instar nymphs were exposed to a single already-mated female parasitoid (1 day old) and removed after 24 h. Subsequently, the nymphs were sprayed at 1, 24 and 48 h post-exposure with 1 × 108 conidial mL−1 suspension. The percentage of parasitism recorded was 22%, 35% and 41% at 1, 24 and 48 h, respectively. The emergence rate varied between 28%, 51% and 49% at 1, 24 and 48 h, respectively. In a subsequent experiment, nymphs of D. citri were sprayed with 1 × 108 conidial mL−1 suspension and then exposed to T. radiata at 1, 24 and 48 h post-spraying to allow for parasitism to occur. The percentage of parasitism recorded was 18%, 27% and 28% at 1, 24 and 48 h, respectively, significantly lower than the parasitism rate recorded in the control (48%). The percentage of emergence vari...
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Chickpea Blight is a devastating disease of chickpea (Cicer areitinum L.) worldwide caused by Ascochyta rabiei (Pass.) Lab. The disease is more disastrous particularly in long cool and humid environmental spells. It results in huge losses... more
Chickpea Blight is a devastating disease of chickpea (Cicer areitinum L.) worldwide caused by Ascochyta rabiei (Pass.) Lab. The disease is more disastrous particularly in long cool and humid environmental spells. It results in huge losses by wiping off all the crop in the desert areas whenever hit its epidemics. To manage this disease, different management strategies are practiced. However, breeding resistance to the host is the best and environmentally safe strategy. During 1970s, the loss of host resistance against the pathogen was reported, so extra ordinary efforts were started by the scientists to enhance the host tolerance towards the pathogen. In this way, relatively simple field screening techniques were followed for breeding and identification of new resistant genotypes. The review sums up the efforts regarding host breeding against chickpea blight involving large scale field screening experiments as well as recent marker assisted breeding using the molecular mapping and QT...
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Over the last century, the global climate has been changing rapidly. Numerous anthropogenic activities have caused an unprecedented increase in the concentrations of atmospheric CO 2 with other gases which consequently resulted in... more
Over the last century, the global climate has been changing rapidly. Numerous anthropogenic activities have caused an unprecedented increase in the concentrations of atmospheric CO 2 with other gases which consequently resulted in increased temperature and altered precipitation. In agriculture ecosystem, insect population dynamics are regulated by top-down forces i.e. predators and parasitoids feed on them and bottom-up forces where host plants regulate herbivore population. Climate change may directly affect all the organism in the trophic system at the same time changes in the first trophic level may subsequently bring changes in the following trophic levels which may further have implications on ecosystem services. Understanding of the way climate change factors may affect tri-trophic interactions may help farmers to adopt future pest management strategies. This review focuses on direct and mediated effects of climate change on plant-herbivore-natural enemy interactions as well a...
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Tamarixia radiata is one of the established biocontrol pests against the major Asian citrus psyllid, Diaphorina citri, a vector of Candidatus Liberibacter that is a causal agent of citrus Huanglongbing (HLB) disease. Updated information... more
Tamarixia radiata is one of the established biocontrol pests against the major Asian citrus psyllid, Diaphorina citri, a vector of Candidatus Liberibacter that is a causal agent of citrus Huanglongbing (HLB) disease. Updated information and regional exploration on biocontrol pests are important elements for effective disease management strategies. In this study, the diversity and parasitism rate of T. radiata populations were evaluated. Due to the importance of the host–parasitoid relationship, the presence of Wolbachia as an endosymbiont was also investigated. The parasitism rate of various T. radiata populations from Ecuador and China ranged between 57.27% and 66.32%, respectively, with a non-significant emergence rate and a statistically similar sex ratio. Sequence analysis of ITS and COI from T. radiata populations was consistent with the morphological hypothesis that the collections represent a single species, whereas phylogeny of the wsp gene confirmed the presence of Wolbachi...
Research Interests: Agronomy, Biology, Genetic Diversity, Parasitism, Wolbachia, and 3 moreParasitoid, Vigna, and Vigna Radiata
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The diamondback moth (DBM) is a destructive pest of crucifer crops. In this study, DBM larvae shown to herbivore induced plant volatiles (HIPVs) that were attractive to adult females exposed in a Y-tube olfactometer. Our results showed... more
The diamondback moth (DBM) is a destructive pest of crucifer crops. In this study, DBM larvae shown to herbivore induced plant volatiles (HIPVs) that were attractive to adult females exposed in a Y-tube olfactometer. Our results showed that olfactory responses of adult females to HIPVs induced by third instar larvae feeding on Barbarea vulgaris were significantly higher (20.40 ± 1.78; mean moths (%) ± SD) than those induced by first instar larvae (14.80 ± 1.86; mean moths (%) ± SD). Meanwhile, a significant concentration of Sulphur-containing isothiocyanate, 3-methylsulfinylpropyl isothiocyanate, and 4-methylsulfinyl-3-butenyl isothiocyanate were detected in HIPVs released by third instar larvae compared to those released by first instar larvae while feeding on B. vulgaris. When the DBM females were exposed to synthetic chemicals, singly and in blend form, a similar response was observed as to natural HIPVs. Our study demonstrated that the relationship between isothiocyanates acting...
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The inoculation methods, the fungal strains, and several other factors are known to influent the success of fungal entomopathogens colonization in plants. The physiological status of the plant could also be another determinant. In the... more
The inoculation methods, the fungal strains, and several other factors are known to influent the success of fungal entomopathogens colonization in plants. The physiological status of the plant could also be another determinant. In the present study, the ability of three strains of Beauveria bassiana and one strain of Metarhizium anisopliae to successfully colonize Citrus limon plants and the influence of seedling age on endophytic colonization success was examined. Three, 4, and 6 months old seedlings were inoculated with 10 mL of 1 × 108 conidial·mL−1 suspensions of each of the four fungal strains via foliar spraying. All fungal strains successfully colonized citrus seedlings and were sustained up to 2 months in colonized plants irrespective of the seedling age, with differences in the mean percentage colonization recorded at various post-inoculation periods among the fungal strains. The highest percent endophytic fungi recovery rate was recorded in the 3 months old seedlings, wher...
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The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) is a very destructive crucifer-specialized pest that has resulted in significant crop losses worldwide. DBM is well attracted to glucosinolates (which act as... more
The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) is a very destructive crucifer-specialized pest that has resulted in significant crop losses worldwide. DBM is well attracted to glucosinolates (which act as fingerprints and essential for herbivores in host plant recognition) containing crucifers such as wintercress, Barbarea vulgaris (Brassicaceae) despite poor larval survival on it due to high-to-low concentration of saponins and generally to other plants in the genus Barbarea. B. vulgaris build up resistance against DBM and other herbivorous insects using glucosinulates which are used in plant defense. Aside glucosinolates, Barbarea genus also contains triterpenoid saponins, which are toxic to insects and act as feeding deterrents for plant specialist herbivores (such as DBM). Previous studies have found interesting relationship between the host plant and secondary metabolite contents, which indicate that attraction or resistance to specialist herbivore D...
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Entomopathogenic fungi (EPF) can be established as endophytes in the host plants to offer a long-term preventive measure for pests and diseases. This practice serves as a better alternative to the common practice of periodic direct... more
Entomopathogenic fungi (EPF) can be established as endophytes in the host plants to offer a long-term preventive measure for pests and diseases. This practice serves as a better alternative to the common practice of periodic direct application of EPF on plants or the target pests as a short-term defense strategy against pests and diseases. These fungal endophytes, aside from their role in pests and diseases prevention, also act as plant growth promoters. Several fungal endophytes have been associated with improvement in plant height, dry and wet weight and other growth parameters. However, many limiting factors have been identified as mitigating the successful colonization of the host plants by EPF. The inoculation methods used have been identified as one, but sadly, this has received little or less attention. Some previous studies carried out comparison between various artificial inoculation methods; foliar application, seedling dipping, soil drenching, seed inoculation, direct inj...
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Entomopathogenic fungi (EPF) have primarily been applied as an inundative approach to manage pests. However, in recent decade multifunctional role of EPF have been documented which provide multiple benefits to host plants when colonized... more
Entomopathogenic fungi (EPF) have primarily been applied as an inundative approach to manage pests. However, in recent decade multifunctional role of EPF have been documented which provide multiple benefits to host plants when colonized as an endophyte. In this study five fungal isolates from the genus Beauveria (three), Isaria (one) and Lecanicillium (one) were evaluated for their ability to colonize common bean, Phaseolus vulgaris and to assess their effects in planta on plant growth promotion and possible negative effects on the two-spotted spider mites, Tetranychus urticae. All the tested isolates in this study were able to endophytically colonize root, stem and even leaves of inoculated plants examined at 7 and 14 days post inoculation, indicating the systemic colonization of EPF. Colonized plants showed increased plant heights, fresh shoot and root weights compared to plants without inoculation. Survivorship of T. urticae significantly differed among the treatments with higher...
Research Interests: Microbiology, Immunology, Medical Microbiology, Biology, Medicine, and 14 moreMicrobial Pathogenesis, Beauveria bassiana, Phaseolus, Endophytic Fungi, Biological control of insect pests, Acari, Phaseolus vulgaris, Fecundity, Biological Pest Control, Mites, Entomopathogenic Fungi, Lecanicillium, Tetranychus urticae, and Isaria fumosorosea
The incorporation of entomopathogenic fungi as biocontrol agents into Integrated Pest Management (IPM) programs without doubt, has been highly effective. The ability of these fungal pathogens such as and to exist as endophytes in plants... more
The incorporation of entomopathogenic fungi as biocontrol agents into Integrated Pest Management (IPM) programs without doubt, has been highly effective. The ability of these fungal pathogens such as and to exist as endophytes in plants and protect their colonized host plants against the primary herbivore pests has widely been reported. Aside this sole role of pest management that has been traditionally ascribed to fungal endophytes, recent findings provided evidence of other possible functions as plant yield promoter, soil nutrient distributor, abiotic stress and drought tolerance enhancer in plants. However, reports on these additional important effects of fungal endophytes on the colonized plants remain scanty. In this review, we discussed the various beneficial effects of endophytic fungi on the host plants and their primary herbivore pests; as well as some negative effects that are relatively unknown. We also highlighted the prospects of our findings in further increasing the a...
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Research Interests:
The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a devastating pest of Citrus spp. The aim of present study was to investigate the development and mortality of ACP on citrus (Citrus sinensis) (healthy... more
The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a devastating pest of Citrus spp. The aim of present study was to investigate the development and mortality of ACP on citrus (Citrus sinensis) (healthy and Huánglóngbìng- (HLB) diseased) and jasmine (Murraya paniculata) plants at various temperatures. Two new Isaria strains were collected from citrus orchards of Fuzhou (China), and HLB-diseased plants were verified by running PCR for 16S gene of Candidatus Liberibacter asiaticus (CLas). Development observations were recorded for egg, nymph and adult stages on all plants and three different temperatures (20, 25 and 30 °C) whereas mortality observations were recorded for the nymph (fifth instar) and adults on all plants at 25 °C. Field collected Isaria strains were belonged to previously reported Chinese strains under Maximum Parsimony (MP) and Maximum Likelihood methods, as well as, CLas isolates were belonged to previously reported Chinese isolates u...
Research Interests: Microbiology, Immunology, Medical Microbiology, Biology, Mortality, and 15 moreMedicine, Phylogeny, Animals, Microbial Pathogenesis, Hemiptera, PEST analysis, Nymph, Citrus Sinensis, Ascomycota, Entomopathogenic Fungi, Insect Development, Insect Vectors, Huanglongbing, Asian citrus psyllid, and Diaphorina citri
Some entomopathogenic fungi species, Isaria fumosorosea, and Hirsutella citriformis were found to be efficient against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). However, the susceptibility to these fungi... more
Some entomopathogenic fungi species, Isaria fumosorosea, and Hirsutella citriformis were found to be efficient against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). However, the susceptibility to these fungi increases when the psyllid infected with Candidatus Liberibacter asiaticus (Las), which is transmitted by D. citri and causes citrus greening disease. In this study, we examined the Las-infected and Las-uninfected D. citri susceptibility to entomopathogenic fungi at different temperature regimes (5-40°C). When D. citri adults exposed to cold temperature (5°C), they showed less susceptibility to entomopathogenic fungi as compared with control (27°C). Irrespective of infection with Las, a significantly positive correlation was observed between temperature and percentage mortality caused by different isolates of I. fumosorosea, 3A Ifr, 5F Ifr, PS Ifr, and H. citriformis isolates, HC3D and 2H. In contrast, a significantly negative correlation was found b...
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Entomopathogenic fungi are rich sources of bioactive secondary metabolites that possess insecticidal properties. The present study reported a novel approach for the identification of insecticidal compounds produced by Lecanicillium... more
Entomopathogenic fungi are rich sources of bioactive secondary metabolites that possess insecticidal properties. The present study reported a novel approach for the identification of insecticidal compounds produced by Lecanicillium lecanii 09 and to assess their toxicity against the diamondback moth Plutella xylostella L. The cyclic peptides groups of toxic substances were separated from L. lecanii 09 through submerged liquid state fermentation. The most abundant toxic metabolite, Bassianolide was purified by high-performance liquid chromatography (HPLC) and its molecular weight and purity were determined by Liquid chromatography - mass spectroscopy (LC-MS), Fourier transformed infrared spectroscopy (FT-IR), and Hnuclear magnetic resonance (NMR) respectively. Subsequently, the toxicity of bassianolide was tested against third instar larvae of P. xylostella at three different concentrations (0.01, 0.1, 0.5 mg/ml). The results showed that higher concentration of 0.5 mg/ml had signific...