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Copyright of Acta Agriculturae Slovenica is the property of Biotechnical Faculty of the University of Ljubljana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study aims to prepare emulsifiable concentrate (EC) and nanoemulsion formulations from the plant essential oils of Lavandula angustifolia (Mill.), Ambrosia maritima (L.), Commiphora myrrha (Nees) Engl., Juniperus virginiana (L.), Rheum palmatum (L.) and Tagetes minuta (L.). The efficiency of these essential oils along with their formulations were compared against the bean aphid, Aphis fabae (Scopoli). Results disclosed that all EC preparations passed the emulsion stability and foam formation tests. The particle droplet size of the nanoemulsions varied from 64.3 to 264.7 nm. The toxicity of EC formulations was slightly higher than the corresponding nanoemulsion formulations. Both EC and nanoemulsion of R. palmatum were the most efficient (LC50 = 1003.60 and 1105.34 mg L−1, respectively). EC preparations had no adverse effects on seed beans. The absence of organic solvents and the high aphicidal activity of EC formulations might make these preparations suitable for controlling A. fabae. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eichhornia crassipes were evaluated in order to investigate the insecticidal activity towards Aphis craccivora adults. The LC50 values were promising and reflected the bio-efficacy of the tested extracts (39 and 42 mg/L), respectively, and reduced the fecundity markedly. Using GC/MS analysis, the major components were n-hexadecanoic, linolenic, hexadecenoic, myristic, stearic acids, linolelaidic acid, methyl ester and some terpenoids, alkaloids, and hydrocarbons. A safety assessment of non-target organisms is essential for the development of new pesticides. In order to guide the rational use of the most potential insecticidal extracts AcF and EtF, the effect of these extracts on body weight, hematological indices, biochemical indicators, and histopathology of some relevant organs of albino rats (as a model for mammals) was investigated. The research outcomes revealed that the LC50 of AcF and EtF extracts had gradually raised body weight for 14 days (p > 0.05). Similarly, there were no remarkable alternations in the complete blood count (CBC); only a slight decrease in the monocytes count (612 ± 159.80 × 103 µL) in the EtF-treated group. There was a notable increase in alanine transferase (ALT) activity (36.73 ± 1.44 IU/L) in the AcF-treated group. No destructive changes were noted with the remaining biochemical parameters. Cholesterol and triglycerides non-significantly increased in the EtF group, whereas, cholesterol levels decreased significantly in the AcF group. In addition, histopathological examination reflected minor changes in AcF and EtF groups in the form of mild inflammation in the lungs and mild vacuolar degeneration in the kidneys, while no lesions were detected in the heart and liver in the same groups. Thus, the present research suggested that AcF and EtF extracts of E. crassipes are safe green insecticides for insect control strategies. [ABSTRACT FROM AUTHOR]

The black bean aphid Aphis fabae constitutes a dangerous pest. The use of pesticides provokes undesirable effect on the environment and the human health. Thus, the research for methods with low negative secondary effect becomes very important. The purpose of this study is the screening of the aphicidal activity of extracts from Marrubium deserti and Hertia cheirifolia. Moreover, the effect of the same treatments was tested on the orientation of A. fabae. Through our study, ANOVA revealed significant differences between the studied essential oils. Those of H. cheirifolia with a concentration of 10000 ppm were the most effective with 96.67% of corrected mortality rate after 6 hours. Whereas for aqueous extracts, the mortality rate were less important and it reached only 30% after 24 h for H. cheirifolia 30% extracted by maceration. For the test of orientation, the results showed that after 24 hours, the essential oils of H. cheirifolia with a concentration of 10000 ppm and the extracts obtained by maceration of the two plants had an important repellency rate superior than 70%. [ABSTRACT FROM AUTHOR]

Based on data from available scientific publications, a review of the insects, trophically related to Impatiens glandulifera in its European invasion zone has been made. As a result, nine insect species (Pristerognatha fuligana, Deilephila elpenor, Xanthorhoe biriviata, Chrysolina herbacea, Siobla sturmi, Impatientinum asiaticum, Aphis fabae, Aphis nasturtii, Phytoliriomyza melampyga) were found on the invasive plant. Of the identified insects, seven species (D. elpenor, X. biriviata, A. fabae, A. nasturtii, C. herbacea, P. fuligana, P. melampyga) are widespread in the country, of which only two – C. herbacea and P. fuligana are associated with I. glandulifera. The remaining two (I. asiaticum and S. sturmi) are not presented in the Bulgarian entomofauna. Тhe potential role of these insects as agents of biological control of populations of I. glandulifera in Bulgaria has been assessed. [ABSTRACT FROM AUTHOR]

Eichhornia crassipes were evaluated in order to investigate the insecticidal activity towards Aphis craccivora adults. The LC50 values were promising and reflected the bio-efficacy of the tested extracts (39 and 42 mg/L), respectively, and reduced the fecundity markedly. Using GC/MS analysis, the major components were n-hexadecanoic, linolenic, hexadecenoic, myristic, stearic acids, linolelaidic acid, methyl ester and some terpenoids, alkaloids, and hydrocarbons. A safety assessment of non-target organisms is essential for the development of new pesticides. In order to guide the rational use of the most potential insecticidal extracts AcF and EtF, the effect of these extracts on body weight, hematological indices, biochemical indicators, and histopathology of some relevant organs of albino rats (as a model for mammals) was investigated. The research outcomes revealed that the LC50 of AcF and EtF extracts had gradually raised body weight for 14 days (p > 0.05). Similarly, there were no remarkable alternations in the complete blood count (CBC); only a slight decrease in the monocytes count (612 ± 159.80 × 103 µL) in the EtF-treated group. There was a notable increase in alanine transferase (ALT) activity (36.73 ± 1.44 IU/L) in the AcF-treated group. No destructive changes were noted with the remaining biochemical parameters. Cholesterol and triglycerides non-significantly increased in the EtF group, whereas, cholesterol levels decreased significantly in the AcF group. In addition, histopathological examination reflected minor changes in AcF and EtF groups in the form of mild inflammation in the lungs and mild vacuolar degeneration in the kidneys, while no lesions were detected in the heart and liver in the same groups. Thus, the present research suggested that AcF and EtF extracts of E. crassipes are safe green insecticides for insect control strategies.

Bioefficacy of insecticidal formulations namely acetamiprid 20 per cent SP (0.4g L-1) of water), imidacloprid 17.8 per cent SL (0.33 mL L-1), quinalphos 25 per cent EC (2.0 mL L-1)), thiamethoxam 25 per cent WG (0.5g L-1)), neem oil 2 per cent (20 mL L-1)), karanj oil 2 per cent (20 mL L-1)) against the aphid, Aphis cracivora Koch in clusterbean is reported. The most effective insecticides were imidacloprid, thiamethoxam and acetamiprid respectively. During the year 2015, maximum population reduction over control was found after 7 d of application of second spray of imidacloprid and thiamethoxam (75.97 and 72.92%) respectively. A similar trend was observed in 2016 and 2017. Thus, imidacloprid was the most effective against Aphis cracivora. [ABSTRACT FROM AUTHOR]

Prey preference of natural enemies is an important parameter used in studies on their efficiency. Feeding preferences of individuals of Coccinella septempunctata (L.) (Coleoptera: Coccinellidae) for the essential prey items, winged and wingless Aphis fabae (Scopoli) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) were evaluated in the laboratory using Manly's preference index. For the C. septempunctata prey preference experiment, equal number of winged and wingless A. fabae and M. persicae were offered to the predator adult stage. The experiment was conducted with 10 replicates. The number of aphids consumed was counted and recorded for every three hours. Two-way analysis of variance was performed to determine the interaction between the consumed aphid and time. In the statistical grouping, the highest consumption was in the first three hours in the wingless individuals, while the lowest consumption was in the 24th winged group. In addition, preferred prey experiments indicated that C. septempunctata consumed the wingless ones more than the winged ones. Index values > 0.5 represents preference for wingless while those < 0.5 represent non-preference for aphid species. [ABSTRACT FROM AUTHOR]

Highlights • Mating preferably occurred with individuals emerging from the same host species. • The males gave the olfactory response to the females reared on the same host species. • Conditional mate choice by host aphid species increased fitness of the progeny. Abstract We used the aphid parasitoid wasp, Lysiphlebus fabarum (Hymenoptera: Braconidae) reared on host aphids Aphis fabae (Hemiptera: Aphididae) and Aphis gossypii to examine whether or not mating preference can be conditioned by the host species on which the wasps were reared. The effect of the parental hosts on the fitness of the progeny was also examined. The results revealed that male and female wasps reared on one host species preferred each other as mates than those individuals reared on a different species. This was demonstrated by counting the number of mating successes and the olfactory response of males to the odor of females that developed in Aphis fabae or A. gossypii. The results also revealed that conditional mate choice mediated by a host species increased the fitness of the female progeny (i.e. larger bodies, shorter developmental time and higher egg load with larger eggs), and led to a higher female sex ratio. Because the particular host species confers fitness on the developed wasps, the fitness traits appear in the progeny when both parents are reared on one host species, but not in the progeny of two parents reared on different host species. [ABSTRACT FROM AUTHOR]

Background: Since larval cannibalism is frequently observed in intensive rearing systems, the regeneration of lost legs is common for the beneficial species Coccinella septempunctata (Coccinella: Coccinellidae) to adapt to the competitive environment, but whether functional recovery occurs in the leg‐regenerated coccinellids remains unknown. To evaluate the functional recovery of regenerated right foreleg after being damaged, the behaviors of leg‐regenerated ladybugs containing predation, attachment, intraspecific competition, prey preference and fecundity were studied in the laboratory. Results: The prey consumption and searching rate of leg‐regenerated ladybugs decreased, and their handling time extended. A significantly reduced attachment coefficient was detected in leg‐regenerated coccinellids. Because of the competitive inferiority, leg‐regenerated ladybugs were greatly hampered in competition with normal opponents, and this inferiority led to a switch of prey preference from big‐sized adults to small‐sized first–second instar nymphs of Paratriozasinica. However, although reduced functional abilities were examined, the leg‐regenerated paternity had a higher reproductive output compared to the normal paternity. Conclusion: Leg‐regenerated ladybugs caused by cannibalism may make an investment tradeoff between egg fecundity and functional recovery. Thus, larval cannibalism potentially improves the offspring production of the biological control agent in complex environments. © 2018 Society of Chemical Industry Since larval cannibalism is common under intensive rearing systems, the leg‐regenerated beneficial species Coccinella septempunctata may make an investment tradeoff between egg fecundity and functional self‐repair to improve progeny production. [ABSTRACT FROM AUTHOR]

We examined the life history consequences of cornicle secretion by Aphis fabae Scopoli in second and fourth instars, and its effects on host suitability for its parasitoid, Lysiphlebus fabarum (Marshall). Cornicle secretion did not affect aphid fecundity, but secretion in the second instar enhanced life table parameters, whereas secretion in the fourth instar affected them negatively, suggesting a higher cost of secretion in later instars. Secretion in either instar improved host suitability for L. fabarum. Although control and treated aphids were parasitized at similar rates, and with similar success, wasps developed faster and emerged as larger adults in aphids that had secreted, regardless of instar. Transgenerational effects were also evident. Progeny emergence was higher when parental wasps developed in fourth instars than in seconds, whether aphids secreted or not, and progeny were larger when parental hosts secreted in the second instar, but not in the fourth. Secreting fourth instars were preferred to controls by L. fabarum females in choice tests, but not secreting second instars, and fourth-instar secretion improved wasp emergence. When control aphids were attacked, second instars were more likely to secrete than fourth instars, whereas the latter were more likely to kick the parasitoid. Cornicle secretion reduced the probability of subsequent secretion events and the frequency of other aphid defensive behaviors, indicating energetic tradeoffs among defensive tactics. Overall, our results revealed that cornicle secretion by immature A. fabae exacts both physiological and behavioral costs and results in improved host suitability for its parasitoid. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Slovenica is the property of Biotechnical Faculty of the University of Ljubljana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Urbanization can alter the composition of arthropod communities. However, little is known about how urbanization affects ecological interactions. Using experimental colonies of the black bean aphid Aphis fabae Scopoli reared on Vicia faba L, we asked if patterns of predator-prey, host-parasitoid and ant-aphid mutualisms varied along an urbanization gradient across a large town in southern England. We recorded the presence of naturally occurring predators, parasitoid wasps and mutualistic ants together with aphid abundance. We examined how biotic (green areas and plant richness) and abiotic features (impervious surfaces and distance to town center) affected (1) aphid colony size, (2) the likelihood of finding predators, mutualistic ants and aphid mummies (indicating the presence of parasitoids), and (3) how the interplay among these factors affected patterns of parasitoid attack, predator abundance, mutualistic interactions and aphid abundance. Aphid abundance was best explained by the number of mutualistic ants attending the colonies. Aphid predators responded negatively to both the proportion of impervious surfaces and to the number of mutualistic ants farming the colonies, and positively to aphid population size, whereas parasitized aphids were found in colonies with higher numbers of aphids and ants. The number of mutualistic ants attending was positively associated with aphid colony size and negatively with the number of aphid predators. Our findings suggest that for insect-natural enemy interactions, urbanization may affect some groups, while not influencing others, and that local effects (mutualists, host plant presence) will also be key determinants of how urban ecological communities are formed. [ABSTRACT FROM AUTHOR]

Four plant extracts: Eucalyptus (Eucalyptus sp), Onion (Allium cepa Linn), Garlic (Allium sativum) and Cinnamon (Cinnamomum sp) with three extraction rates (0, 1 and 3) % in 2016 and 2017 seasons were used against aphid population in broad bean (Vicia faba). Some plants characteristic; Plant Height (cm), Fresh Weight.Plant-1 (g), Dry Weight.Plant-1 (g), Number of Pods.Plant-1, and aphid's dead number after 6 hours and 24 hours were taken. Eucalyptus affected significantly on Number of Pods.Plant-1compared with the other extraction (7.416). As the extraction rate increased, all parameters increased. Pearson's correlation test for traits in 2017 season indicated that there were a significant strong correlate and better than 2016 season among Number of Pods .Plant-1, Fresh Weight.Plant-1 (r = 0.770**), Dry Weight .Plant-1 (r = 0.816**), and M24 (r = 871**). Based on Number of Pods.Plant-1, the best interaction between the season, extraction types, and extraction rates, was a combination of the 2017 season x Eucalyptus extraction x 1% Extraction rate. [ABSTRACT FROM AUTHOR]

Fourteen 1H-pyrazole-5-carboxylic acid derivatives containing oxazole and thiazole rings were synthesized and characterized by ¹H NMR, mass spectrometry and elemental analysis. Most target compounds were obtained in overall yields in the range of 30-50%. The insecticidal activities of these new compounds against Aphis fabae were evaluated. The bioassays' results indicate that some of these compounds exhibit good activities, especially compound 7h which shows 85.7% mortality against A. fabae at a concentration of 12.5 mg/L. This activity is comparable to that of the commercial insecticide imidacloprid. [ABSTRACT FROM AUTHOR]

Reciprocal selection between aphids, their protective endosymbionts, and the parasitoid wasps that prey upon them offers an opportunity to study the basis of their coevolution. We investigated adaptation to symbiont-conferred defense by rearing the parasitoid wasp Lysiphlebus fabarum on aphids ( Aphis fabae) possessing different defensive symbiont strains ( Hamiltonella defensa). After ten generations of experimental evolution, wasps showed increased abilities to parasitize aphids possessing the H. defensa strain they evolved with, but not aphids possessing the other strain. We show that the two symbiont strains encode different toxins, potentially creating different targets for counter-adaptation. Phenotypic and behavioral comparisons suggest that neither life-history traits nor oviposition behavior differed among evolved parasitoid lineages. In contrast, comparative transcriptomics of adult female wasps identified a suite of differentially expressed genes among lineages, even when reared in a common, symbiont-free, aphid host. In concurrence with the specificity of each parasitoid lineages' infectivity, most differentially expressed parasitoid transcripts were also lineage-specific. These transcripts are enriched with putative venom toxins and contain highly expressed, potentially defensive viral particles. Together, these results suggest that wild populations of L. fabarum employ a complicated offensive arsenal with sufficient genetic variation for wasps to adapt rapidly and specifically to their hosts' microbial defenses. [ABSTRACT FROM AUTHOR]

Background: Aphids are major vectors of plant viruses. Common bean (Phaseolus vulgaris L.) and maize (Zea mays L.) are important crops that are vulnerable to aphid herbivory and aphid-transmitted viruses. In East and Central Africa, common bean is frequently intercropped by smallholder farmers to provide fixed nitrogen for cultivation of starch crops such as maize. We used a PCR-based technique to identify aphids prevalent in smallholder bean farms and next generation sequencing shotgun metagenomics to examine the diversity of viruses present in aphids and in maize leaf samples. Samples were collected from farms in Kenya in a range of agro-ecological zones. Results: Cytochrome oxidase 1 (CO1) gene sequencing showed that Aphis fabae was the sole aphid species present in bean plots in the farms visited. Sequencing of total RNA from aphids using the Illumina platform detected three dicistroviruses. Maize leaf RNA was also analysed. Identification of Aphid lethal paralysis virus (ALPV), Rhopalosiphum padi virus (RhPV), and a novel Big Sioux River virus (BSRV)-like dicistrovirus in aphid and maize samples was confirmed using reverse transcription-polymerase chain reactions and sequencing of amplified DNA products. Phylogenetic, nucleotide and protein sequence analyses of eight ALPV genomes revealed evidence of intra-species recombination, with the data suggesting there may be two ALPV lineages. Analysis of BSRV-like virus genomic RNA sequences revealed features that are consistent with other dicistroviruses and that it is phylogenetically closely related to dicistroviruses of the genus Cripavirus. Conclusions: The discovery of ALPV and RhPV in aphids and maize further demonstrates the broad occurrence of these dicistroviruses. Dicistroviruses are remarkable in that they use plants as reservoirs that facilitate infection of their insect replicative hosts, such as aphids. This is the first report of these viruses being isolated from either organism. The BSRV-like sequences represent a potentially novel dicistrovirus infecting A. fabae. [ABSTRACT FROM AUTHOR]

Aphid species can be polyphagous, feeding on multiple host plants across genera. As host plant species can have large variation in their phloem composition, this can affect aphid fitness and honeydew composition. Previous research showed significant intraspecific genotype variation in the composition of the honeydew carbohydrates of the black bean aphid Aphis fabae, with the ant attractant trisaccharide melezitose showing especially large variation across different genotypes. In this study, we test if variation in melezitose and carbohydrate composition of aphid honeydew could be linked to the adaptation of specific aphid genotypes to particular host plants. To this end, 4 high and 5 low melezitose secreting genotypes of the black bean aphid Aphis fabae were reared on 4 common host plants: broad bean, goosefoot, beet, and poppy. The carbohydrate composition, and in particular melezitose secretion, showed important aphid genotype and host plant interactions, with some genotypes being high melezitose secreting on 1 host plant but not on another. However, the interaction effects were not paralleled in the fitness measurements, even though there were significant differences in the average fitness across the different host plants. On the whole, this study demonstrates that aphid honeydew composition is influenced by complex herbivore-plant interactions. We discuss the relevance of these findings in the context of ant-aphid mutualisms and adaptive specialization in aphids. [ABSTRACT FROM AUTHOR]

Dorsal and ventral sides of the forewing of Aphis fabae (Scopoli 1763) (Sternorrhyncha, Hemiptera) were examined by scanning electron microscopy. Reinforcement elements on their surface as well as scale-like elements were described. Using histological methods, cross-sections of the material were done. They showed a two-layered membrane with a circular foramen inside. The course of veins and places of their bifurcation were followed. Common stem of radius (R), media (M), and cubitus anterior (CuA) veins were composed of separate tracheae, which ran separately at the beginning, then continued in a single tunnel, and finally disappeared. Nerves were not observed. Neither were tracheae visible on the further course of those veins. The presence of a devoid-of-trachea costal vein was confirmed. Under scanning electron microscope, convex reinforcements on dorsal side of the wing turned out to be more sclerotized parts of chitin, not giving a zigzag-like profile of the wing on sections. In this paper, we show for the first time a cross-section of a very delicate wing of an aphid representative. [ABSTRACT FROM AUTHOR]

Life history parameters of the ladybird populations, Propylea quatuordecimpunctata (L.) (Coleoptera: Coccinellidae), collected at two locations in Iran (Karaj and Sari) were recorded on two prey species, Aphis fabae Scopoli, 1763 and Aphis gossypii Glover, 1877 (Homoptera: Aphididae). The duration of most developmental stages (egg, first, second and third instar larvae) of two local populations of P. quatuordecimpunctata differed significantly, except for the fourth instar and pupal periods. A comparison of life table parameters between the two populations with different preys, showed that the net reproductive rate (R0) was not significantly different (P > 0.05). The intrinsic rate of increase (r), the mean generation time (T) and the finite rate of increase (λ) of the population from Sari on A. gossypii, differed significantly from the same population fed on A. fabae (P < 0.05). Our results demonstrated that reproductive traits of two populations of P. quatuordecimpunctata were affected by the geographic conditions and the prey species. [ABSTRACT FROM AUTHOR]

1. Aphid-tending ants that feed on honeydew have evolved strategies against aphidophagous insects and tune their aggressive behaviour according to the level of danger for their trophobionts. Here we investigate how Lasius niger Linnaeus ( Hymenoptera: Formicidae) ants react to different instars of Episyrphus balteatus De Geer ( Diptera: Syrphidae) hoverflies which vary in their voracity and defensive abilities. 2. During pairwise encounters, early syrphid instars (eggs, L1, and L2 larvae) elicited lower aggression scores compared to third larval instars ( L3), which was intensively bitten by ants. L3 tried to escape from ants by releasing a sticky and toxic secretion over biting ants that died or underwent severe morbidity. 3. In a standardised system including the host plant, aphid, tending ant, and hoverfly, the ability of ants to protect an Aphis fabae Scopoli ( Hemiptera: Aphididae) colony was evaluated. Early E. balteatus instars placed onto the plant elicited no mobilisation of ants, which often removed the hoverfly successfully. Eggs and early instars appeared as the weak links for integrated pest management by hoverfly auxiliaries. 4. In contrast, L3 induced the number of ant patrollers to increase at a local scale without any further recruitment from inside the ant nest. L3 syrphids were quite efficient at gluing ants with defensive secretions and at resisting to removal attempts by ants. 5. While supporting the assumption that ants tune their defensive response to the aphidophagous predator, the present results also showed a lack of efficient protection of their trophobionts from the most voracious late syrphid instar. [ABSTRACT FROM AUTHOR]

The facultative endosymbionts Hamiltonella defensa and Regiella insecticola are commonly found in aphids. They are linked with various ecological benefits but generally occur at low prevalence, which indicates a possible harbouring cost. Little is known about how the presence of facultative endosymbionts is reflected in honeydew composition. Honeydew is the key mediator of the mutualism between aphids and their tending ants. The present study examines whether endosymbionts have an influence on aphid honeydew quality by comparing the amino acid and carbohydrate concentrations between infected and uninfected aphids. To this end, two genetic lines of the aphid Aphis fabae Scopoli are experimentally infected with different strains of Hamiltonella and Regiella. Infected aphids are shown to have reduced concentrations of amino acids in the honeydew compared with uninfected aphids. However, the presence of endosymbionts has no effect on the absolute amount of carbohydrates produced. Nevertheless, interclonal variation in honeydew composition between aphid genotypes is observed for both carbohydrate and amino acid production. These results imply that the nutritional value of honeydew depends on aphid genotype, as well as on the presence of secondary bacterial endosymbionts, which suggests that there is a physiological cost of harbouring endosymbionts and which could also impact aphid attractiveness to tending ants. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effect of aqueous extracts of dried chamomille (Matricaria chamomilla L.), in concentrations of 2%, 5% and 10%, and fresh parts of this plant, in concentrations of 10%, 20% and 30% on survival of black bean aphid (Aphis fabae Scop.) on the leaves of broad bean (Vicia faba L.) variety "Bartek" and on feeding of Colorado potato beetle (Leptinotarsa decemlineata Say.) on the leaves of potato (Solanum tuberosum L.) variety "Bellarosa". In these researches on impact of water extracts from chamomille on mortality of wingless females and larvae of black bean aphid, 15 laboratory's observations in the 8-hour intervals was made. In the studies of the effects of aqueous extracts of chamomille on the dynamics of Leptinotarsa decemlineata feeding on the potato leaves, 4 laboratory's observations in 12-hour intervals was made. Observations were carried out in 6 replicates divided into L2 and L4 larvae stages. Aquatic extracts of chamomile limited the survival of black bean aphid larvae and wingless females - the higher the concentration, the stronger the effects of the extract, where young insects were found to be more susceptible. Extracts of the dried plant whose concentration was below 5% and extracts of the fresh plant whose concentration was below 20% were found to be ineffective against black bean aphids. In all the analysed concentrations the aquatic extracts of chamomile were found to be ineffective against L2 and L4 larvae of Colorado potato beetle. [ABSTRACT FROM AUTHOR]

1. Insects are commonly infected with bacterial endosymbionts. In addition to the costs and benefits associated with harbouring these symbionts, their rates of vertical and horizontal transmission are important determinants of symbiont prevalence. 2. Aphids are cyclical parthenogens and show virtually perfect maternal transmission of endosymbionts during asexual reproduction. Less clear is the role of the annual sexual generation, during which overwintering eggs are produced. Data from pea aphids ( Acyrthosiphon pisum Harris) suggest that maternal transmission failures and horizontal transmission via males may occur under sexual reproduction at least occasionally. No such data exist for other aphid species. 3. In the present study, the rates of maternal and paternal transmission of facultative endosymbionts during sexual reproduction in the black bean aphid, Aphis fabae (Scopoli) were examined. Crosses were performed between clones infected with Hamiltonella defensa, clones infected with Regiella insecticola and clones without facultative endosymbionts, and eggs were overwintered under three different conditions. 4. Only one of 205 offspring from crosses testing for maternal transmission failed to inherit the symbiont present in the maternal clone, and in crosses testing for horizontal transmission, only one of 412 offspring acquired a facultative symbiont from the father. 5. These results show that in A. fabae, maternal transmission of H. defensa and R. insecticola is extremely reliable also during sexual reproduction, indicating that maternal transmission failures are unlikely to exert a significant influence on frequencies of infection in the field. Paternal transmission of endosymbionts was exceedingly rare, suggesting that this route of horizontal transmission may be less important than hitherto assumed. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effects of various petroleum-derived substances, namely petrol, diesel fuel and spent engine oil, on life history traits and population dynamics of the black bean aphid Aphis fabae Scop. and on growth and chemical composition of its host plant Vicia faba L. Each substance was tested separately, using two concentrations (9 g kg and 18 g kg). The experiment was conducted in four replications (four pots with five plants in each pot per treatment). Plants were cultivated in both control and contaminated soils. After six weeks from soil contamination and five weeks from sowing the seeds, observations of the effect of petroleum-derived substances on traits of three successive generations of aphids were conducted. Aphids were inoculated separately on leaves using cylindrical cages hermetically closed on both sides. Contamination of aphid occurred through its host plant. Results showed that all tested substances adversely affected A. fabae life history traits and population dynamics: extension of the prereproductive period, reduction of fecundity and life span, reduction of the population intrinsic growth rate. In broad bean, leaf, roots, and shoot growth was also impaired in most conditions, whereas nutrient and heavy metal content varied according to substances, their concentration, as well as plant part analysed. Results indicate that soil contamination with petroleum-derived substances entails far-reaching changes not only in organisms directly exposed to these pollutants (plants), but also indirectly in herbivores (aphids) and consequently provides information about potential negative effects on further links of the food chain, i.e., for predators and parasitoids. [ABSTRACT FROM AUTHOR]

Plants are the nature's biochemical factories. They bio-synthesize a diverse array of different natural products, such as alkaloids, terpenes and terpenoids, phenolic compounds, flavonoids and coumarins through their structural mechanisms to reduce insect attacks, both constitutive and inducible, while insects have evolved strategies to overcome these plant defenses. There is a widespread effort to find new pesticides, and currently it is focused on natural compounds such as flavonoids, coumarins, terpenoids, and phenolics from diverse botanical families from arid and semi-arid lands. Algeria by the diversity of its habitats has a very diverse flora. Some of these plants have very interesting insecticidal properties. The aim of this study is to evaluate the insecticidal effect of the plant Artemisia judaica L. (Asteraceae). The crude ethanol extract of the plant A. judaica was tested on the black bean aphid Aphis fabae Scop. Four doses (12.5, 6.25, 3.12 and 1.56 mg mL-1) were tested on contact wingless adults. The results have showed that the tested extract has been very powerful to aphids. At the highest dose 12.5 mgmL-1, the 100% of mortality were recorded 2 hours after treatment, and for the lowest dose (1.56 mgmL-1) it was after 96 hours. The LD50 calculated 2 hours after treatment from the regression lines Probit = £ (doses) shows that it is 2.75 mgmL-1. This powerful insecticidal activity of the tested crude extract could be due to the richness of the plant on phenolics compounds known for their bio-insecticide action. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effect of aqueous extracts of dried mint (Mentha piperita L.) in concentrations of 2%, 5% and 10%, and fresh parts of this plant, in concentrations of 10%, 20% and 30% on feeding of pea leaf weevil (Sitona lineatus L.) and survival of black bean aphid (Aphis fabae Scop.) on the leaves of broad bean (Vicia faba L.), variety "Bartek". In the studies of the effects of aqueous extracts of mint on the dynamics of Sitona lineatus feeding on the beans leaves, 9 laboratory's observations in 12-hour intervals was made. Leaves injuries on their edge surface caused by adult individuals were measured. Observations were carried out in 6 replicates divided into males and females. In these researches on impact of water extracts from mint on mortality of wingless females and larvae of black bean aphids, 14 laboratory's observations in the 8-hour intervals was made. Aqueous extracts of dry and fresh peppermint significantly limited the feeding of pea leaf weevil females, and the extracts from dried material were more effective. Extracts from peppermint caused mortality of black bean aphid larvae compared to wingless females to a greater extent, and the higher the concentration of the extract, the more beneficial effect was observed. An extract from dried material at a concentration of 2% was too weak to effectively combat the larvae of A. fabae, while in the case of aphid females, an effectiveness was only demonstrated for the extracts at the highest concentrations, i.e., 10% of dried and 30% of fresh peppermint. [ABSTRACT FROM AUTHOR]

Background: Insect parasitoids are under strong selection to overcome their hosts' defences. In aphids, resistance to parasitoids is largely determined by the presence or absence of protective endosymbionts such as Hamiltonella defensa. Hence, parasitoids may become locally adapted to the prevalence of this endosymbiont in their host populations. To address this, we collected isofemale lines of the aphid parasitoid Lysiphlebus fabarum from 17 sites in Switzerland and France, at which we also estimated the frequency of infection with H. defensa as well as other bacterial endosymbionts in five important aphid host species. The parasitoids' ability to overcome H. defensa-mediated resistance was then quantified by estimating their parasitism success on a single aphid clone (Aphis fabae fabae) that was either uninfected or experimentally infected with one of three different isolates of H. defensa. Results: The five aphid species (Aphis fabae fabae, A. f. cirsiiacanthoides, A. hederae, A. ruborum, A. urticata) differed strongly in the relative frequencies of infection with different bacterial endosymbionts, but there was also geographic variation in symbiont prevalence. Specifically, the frequency of infection with H. defensa ranged from 22 to 47 % when averaged across species. Parasitoids from sites with a high prevalence of H. defensa tended to be more infective on aphids possessing H. defensa, but this relationship was not significant, thus providing no conclusive evidence that L. fabarum is locally adapted to the occurrence of H. defensa. On the other hand, we observed a strong interaction between parasitoid line and H. defensa isolate on parasitism success, indicative of a high specificity of symbiont-conferred resistance. Conclusions: This study is the first, to our knowledge, to test for local adaptation of parasitoids to the frequency of defensive symbionts in their hosts. While it yielded useful information on the occurrence of facultative endosymbionts in several important host species of L. fabarum, it provided no clear evidence that parasitoids from sites with a high prevalence of H. defensa are better able to overcome H. defensa-conferred resistance. The strong genetic specificity in their interaction suggests that it may be more important for parasitoids to adapt to the particular strains of H. defensa in their host populations than to the general prevalence of this symbiont, and it highlights the important role symbionts can play in mediating host-parasitoid coevolution. [ABSTRACT FROM AUTHOR]

The effects of methanolic and aqueous leaf extracts of the aphid resistant cultivar, CV-12 of broad bean (Vicia faba) on the behavior and mortality of the black bean aphid, Aphis fabae were compared. The main objective of the study was to assess the effects of extracts of V. faba leaves an available insecticide against A. fabae. The results showed that the aqueous leaf extracts of the cultivar CV-12 had a repulsive effect against A. fabae (aver. 1.3 adults / leaf) compared to methanolic leaf extracts of the same cultivar (aver. 3.7 adults / leaf). The results revealed that the methanolic extracts had a toxic effect induced a high A. fabae mortality that reached up to 65.71% compared to the aqueous leaf extracts (mortality rate = 1.43%). The present study suggests that extracts from leaves of resistant cultivar CV-12 have insecticidal and repellent properties against A. fabae and could be used as an alternative of chemical insecticides in an integrated pest management program to A. fabae. [ABSTRACT FROM AUTHOR]

Laboratory experiments were carried out to study some biological aspects of the seven spotted ladybird beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae) reared on four different artificial diets and two natural prey species (Aphis fabae and Rhopalosiphum padi) under laboratory conditions of 25±2 °C and 65±5 % R.H. Data indicated a positive correlation between food type (artificial ornatural) and biological characteristics of the predator. A. fabae was the best prey for C. septempunctata, as the incubation periods of eggs was (4.58 days), the hatchability percentage (93.6%), eggs mortality (6.4%) and shortest total larval period (15.15 days) were recorded. The total larval mortality was the lowest (4%) when larvae were fed on 4th instar larvae of A. fabae. Feeding on natural preys, specially, on A. fabae, led to longer longevity periods (57.06 days for females and 40.96 days for males) of adults than those fed on the artificial diets. Also, females resulted from feeding on A. fabae deposited highest numbers of eggs (565.67 eggs/ female). R. padi, followed A. fabae as a good diet for rearing C. septempunctata. Among four artificial diets, diet (B; dried eggs yolk) was the best; as the incubation period of egg recorded (5.7 days), hatchability percentage (77.20%), mortality percentage of eggs (22.8%), total larval period (19.08 days), total larval mortality (24%) and longevity periods were (57.37 days for females and 33.81 days for males). Females resulted from feeding on diet (B) deposited (212.13 eggs/ female). [ABSTRACT FROM AUTHOR]

It has become increasingly evident that many organisms rely on microbial symbionts for defense against natural enemies, but the ecological importance of defensive symbionts for natural communities still needs to be investigated. A well-known example is Hamiltonella defensa, a heritable endosymbiotic bacterium commonly found in aphids. Laboratory experiments have shown that H. defensa strongly protects aphids against parasitic wasps (parasitoids), although this protection is not equally effective against different species of parasitoids, or even different genotypes of the same species. These results suggest that H. defensa plays an important role in reducing aphid mortality by parasitoids and presumably affects the community composition of parasitoids relying on aphids as a resource. However, there is little evidence that this is indeed the case under natural conditions. We tested this in a field experiment with black bean aphids ( Aphis fabae) by setting up replicated field plots with genetically identical aphids that did or did not harbor H. defensa and following their colonization by natural enemies over a growing season. We observed a clear reduction in parasitism of symbiont-protected aphids, particularly by the parasitoids posing the highest risk. However, protected aphids did not develop larger populations than unprotected ones, possibly reflecting the balancing effect of costs associated with harboring H. defensa. We also observed shifts in the parasitoid species composition on aphids protected by H. defensa, showing that defensive symbionts have the potential to alter the diversity and structure of food webs, with likely consequences for their function and stability. [ABSTRACT FROM AUTHOR]

Five degree of temperatures was tested from 10 to 30°C, Aphis craccivora, was reared on two statuses of bean leaves young and old (Nbrasca variety). Aphid insects were developed faster and had a higher mean relative growth rate and higher intrinsic rate of increase on young than on old leaves of bean, respectively. At temperature 25°C, it was more performance for aphid's development and rearing comparing by other degrees. The intrinsic rate of increase is strongly correlated with the mean relative growth rate during development for Aphis craccivora reared on both young and old leaves of bean plants from 10 to 25°C. [ABSTRACT FROM AUTHOR]

1. The aphid Aphis fabae ( Scopoli) is facultatively tended by Lasius niger ( Linnaeus) ants. Previously, we found that A. fabae colonies can be made up of several clones, and that clones display significant differences in the composition of their honeydew sugars, especially in the amount of the ant attractant sugar melezitose that they produce. 2. These clonal differences could greatly impact the strength of the mutualistic interaction with ants as well as the aphids' fitness. 3. Hence, the aim of this study was to compare the fitness of different A. fabae clones that differed in their melezitose secretion, and whether or not they were tended by ants. 4. Individual fitness indices, colony growth, and alate production of single-clone aphid colonies were analysed. 5. The results demonstrate that the fitness consequences of ant attendance critically depend on an interaction between levels of melezitose production. In particular, we show that high-melezitose secreting clones produce fewer alates and hence might have a lower dispersal ability in the presence of ants. 6. Furthermore, these data confirm previous evidence that ant attendance is costly and results in the production of fewer apterae. [ABSTRACT FROM AUTHOR]

Parasitoid host selection behaviour has been extensively studied in experimentally simplified tritrophic systems formed by one single food chain (one plant, one herbivore and one parasitoid species). The "Mother knows best" hypothesis predicts that the preference for a plant-host complex should be positively correlated with plant quality for offspring performance. We studied the host selection behaviour of the generalist endoparasitoid Aphidius matricariae towards the black bean aphid Aphis fabae in the intercrop system including Vicia faba as a focal plant and its companion plant Camelina sativa. Dual-choice laboratory bioassays revealed that parasitoid females preferred to orientate towards (1) the plant-aphid complex over the non-infested plant whatever the complex (2) the C. sativa-A. fabae complex over the V. faba-A. fabae complex. In dual choice attack rate bioassays, parasitoid females showed more interest towards the aphids on C. sativa but paradoxically chose to oviposit more in aphids on V. faba. Ultimately, parasitoids that had developed on the V. faba-A. fabae complex exhibited better fitness parameters. By demonstrating that parasitoid females were able to discriminate the aphid host that offered the highest fitness to their offspring but selected beforehand the least suitable plant-aphid complex, we provide key insight into the disruption in their host selection behaviour potentially triggered by diverse habitats. This suggests that the "Mother knows best" hypothesis could be thwarted by increasing the complexity of the studied systems. [ABSTRACT FROM AUTHOR]

We collected developmental, survival, and reproduction data for Aphis fabae Scopoli (Hemiptera: Aphididae) reared on faba bean, Vicia faba L. 'Sevilla' at four constant temperatures (15, 20, 25, and 30°C), 70% relative humidity, and a photoperiod of 16:8 (L:D) h. The highest intrinsic rate of increase (r = 0.4347 d-1) and finite rate (λ = 1.5445 d-1) were observed at 25°C. The population projection based on the age-stage, two-sex life table quantitatively revealed the growth potential and stage structure of the aphid. We have included the following suggestions to aid researchers in life table studies: 1) The bootstrap method should be used to estimate the variance and SEs of developmental time, survival rate, fecundity, and population parameters. 2) The required number of bootstraps is dependent on the life table data--the higher the variation among individuals, the higher the number of bootstraps should be. In most cases, we suggest that 100,000 bootstraps should be used to obtain a stable estimate of variance and SEs. 3) Computer projection based on the age-stage, two-sex life table should be used to reveal the stage structure during population growth. 4) We used a simple equation based on the total fecundity, survival rate to adult stage, and first reproductive age to detect possible errors in life table parameters. 5) To assist readers in comprehending results, life table studies should include the cohort size, preadult survival rate, number of emerged female adults, mean fecundity, survival and fecundity curves, and population parameters. [ABSTRACT FROM AUTHOR]

Prey preference of natural enemies is an important parameter used in studies on their efficiency. Feeding preferences of individuals from two populations of Propylea quatuordecimpunctata (L.) (Coleoptera: Coccinellidae) for the essential prey items, Aphis fabae Scopoli, 1763 andAphis gossypii Glover, 1877 (Homoptera: Aphididae) were evaluated in the laboratory using Manly's β preference index (β). For the predator preference experiment, equal numbers of A. fabae and A. gossypii were offered to the predator. The experiment was conducted on a broad bean leaf disc with 20 replicates. After 24 h, the unconsumed aphids were counted. Individuals of P. quatuordecimpunctata from both populations consumed more A. gossypii [Karaj population (mean ± SE): 28.15 ± 1.04 and Sari population 34.35 ± 0.51] than A. fabae (Karaj population: 17.95 ± 0.64 and Sari population: 17.7 ± 1.01). The values of Manly's β preference index (β) for A. gossypii were 0.73 ± 0.01 and 0.77 ± 0.01 for the Karaj and Sari populations, respectively and for A. fabae were 0.26 ± 0.01 and 0.22 ± 0.01 for the Karaj and Sari populations, respectively. Comparison of the preference indices using a t-test revealed significant differences between the prey preferences of those from the Sari population (t = 22.53, df = 38, P < 0.0001) and the Karaj population (t = 26, df = 38, P < 0.0001). These results reveal that P. quatuordecimpunctata from the two populations prefer A. gossypii over A. fabae. [ABSTRACT FROM AUTHOR]

This study was on the effect of three species of aphids (Aphis fabae, Macrosiphoniella sanborni, Brevicoryne brassicae) on the survival, growth and development of the immature stages of the aphidophagous coccinellids Coccinella septempunctata, Ceratomegilla undecimnotata, Propylea quatuordecimpunctata and Oenopia conglobata. The percentage survival was lowest, immature development most prolonged and the adults the lightest when these predators were fed on B. brassicae. In addition, C. septempunctata and C. undecimnotata performed better when fed on M. sanborni (74.1 and 72.0% total immature survival, respectively) than P. quatuordecimpunctata and O. conglobata (25.0 and 13.8% total immature survival, respectively). In addition, the host plant of A. fabae also had a significant effect on the performance of the predators. These coccinellids survived best, had shorter developmental times and were heavier as adults when fed on A. fabae reared on Vicia faba than on Phaseolus vulgaris. These results may be useful for improving the effectiveness of biological control practice and the production of coccinellids in an insectary. [ABSTRACT FROM AUTHOR]

In this research, the estimation of adult and nymph stages and adult of Aphis fabae was investigated using artificial neural network. Determining A. fabae nymph stages is difficult. Morphometric study of different parts of an insect's body is needed to obtain an index to distinguish between different immature stages. The study was aimed to develop a model of A. fabae nymph stages and adult using length of hind tibia, antenna and body length. It was found that the constructed artificial neural network (ANN) exhibited high performance for predicting A. fabae nymph stages. Correlation was 99% and the estimation of the best ANN model was determined to be 0.016289 at epoch 18. Software computing techniques are very useful tools for precision agriculture and also determining which method gives the most accurate result. [ABSTRACT FROM AUTHOR]

This study evaluated the use of Lecanicillium muscarium and Simplicillium lamellicola isolates, the commercial bioinsecticide Verticillium lecanii and two different insecticides against Aphis fabae at 20°C and 25°C. Dead and live individuals were counted daily following treatment, and Lethal time (LT)50 and LT90 values of entomopathogenic fungi (L. muscarium, S. lamellicola and V. lecanii) and insecticides (azadirachtin and imidacloprid) were calculated. LT50 values for L. muscarium, S. lamellicola, V. lecanii, azadirachtin and imidacloprid at 20°C were 1.77, 2.13, 2.33, 1.46 and 0.90/day, respectively. LT50 values at 25°C were 1.93, 1.96, 2.03, 1.28 and 0.86/day, respectively. LT90 values at 20°C were 4.49, 5.28, 5.13, 3.61 and 2.37, and LT90 values at 25°C were 4.46, 5.11, 5.03, 3.43 and 2.21, respectively. At the end of Day 7, death ratios were approximately 100% for all treatment groups at both temperatures. Comparisons of the fiducial limits showed that LT values did not vary significantly between temperatures. [ABSTRACT FROM AUTHOR]

Camelina sativa is a Brassicaceae that was commonly cultivated in Europe until the nineteenth century. Recently, it has received much interest as an alternative oil seed crop because of its particular oil composition and low requirements in terms of agronomic inputs and its resistance to some Brassicaceae-chewing insects. However, little is known about the consequences of its reintroduction on piercing-sucking insect pests that are not Brassicaceae specialists but that are likely to transmit phytoviruses. In this context, laboratory experiments were conducted to investigate the potential colonization of camelina by four major aphid species of northern France. Orientation tests, feeding behavior assessed by electrical penetration graph, and demographic bioassays showed that the polyphagous species Aphis fabae (Scop) and Myzus persicae (Sulzer) were able to land, feed, and reproduce on the plant. They even fed and performed better on camelina than the Brassicaceae specialist Brevicoryne brassicae (L.). Surprisingly, to a lesser extent, C. sativa could also be a suitable host for the cereal specialist Rhopalosiphum padi (L.). The colonization ability of camelina by the different aphids is discussed in terms of the degree of specialization and physicochemical characteristics of the plant. Camelina may therefore constitute a reservoir for aphid species issued from surrounding crops and their associated pathogens. [ABSTRACT FROM AUTHOR]

1. Hosts are often targeted by multiple species of parasites, leading to a confluence of selective pressures on them. In response, hosts may either evolve defences that act very generally, or specific defences against particular parasites. Aphids are attacked by multiple species of endoparasitoid wasps, and there is clear evidence that heritable endosymbionts can confer resistance against some of these wasps. Less clear is how symbiont-conferred resistance in a single host acts against multiple parasitoid species. 2. This question was addressed in the black bean aphid, Aphis fabae (Scopoli). Unprotected aphids and aphids protected by three different strains of the defensive endosymbiont Hamiltonella defensa were exposed to four species of parasitic wasps: the parthenogenetic species Lysiphlebus fabarum (Marshall), which was represented by three different asexual lines, and the sexual species Aphidius colemani (Viereck), Binodoxys angelicae (Halliday), and Aphelinus chaonia (Walker). 3. Hamiltonella defensa provided strong protection against L. fabarum and Aphidius colemani, but there was no evidence that H. defensa-infected aphids were more resistant to the other parasitoid species. While Aphidius colemani was virtually unable to parasitise any aphids harbouring H. defensa, there was variation among the three asexual lines of L. fabarum in how susceptible they were to the defence provided by the different symbiont strains, resulting in a significant genotype-by-genotype interaction. 4. The present results suggest that symbiosis with H. defensa does not provide aphids with a general defence against parasitoid wasps, possibly because some species have evolved specific counter adaptations or because biological differences preclude the symbiont's effectiveness against these species. [ABSTRACT FROM AUTHOR]

Determination of attractive and avoidance behavior of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) is very important in the concomitant use of Beauveria bassiana for control of Aphis fabae (Hemiptera: Aphididae). We investigated the olfactory response of the predatory insect H. variegata when receiving odors pertaining to Aphis fabae infected by B. bassiana EUT116 at 0-, 24-, 48-, and 72-h intervals in a Y-tube olfactometer set-up. Behavioral assays were conducted to assess the ability of adult H. variegata to avoid A. fabae infected with B. bassiana conidia on plants. In these experiments, H. variegata exhibited significant attraction towards the control when the predator alternative option was B. bassiana with 24-h intervals (P = 0.04) and 48- and 72-h intervals (P < 0.01 in both cases). We suggest that under laboratory conditions H. variegata could detect and avoid B. bassiana conidia; thus, B. bassiana would be a negligible threat to this predator. [ABSTRACT FROM AUTHOR]

Host-parasitoid interactions may lead to strong reciprocal selection for traits involved in host defense and parasitoid counterdefense. In aphids, individuals harboring the facultative bacterial endosymbiont, Hamiltonella defensa, exhibit enhanced resistance to parasitoid wasps. We used an experimental evolution approach to investigate the ability of the parasitoid wasp, Lysiphlebus fabarum, to adapt to the presence of H. defensa in its aphid host Aphis fabae. Sexual populations of the parasitoid were exposed for 11 generations to a single clone of A. fabae, either free of H. defensa or harboring artificial infections with three different isolates of H. defensa. Parasitoids adapted rapidly to the presence of H. defensa in their hosts, but this adaptation was in part specific to the symbiont isolate they were evolving against and did not result in an improved infectivity on all symbiont-protected hosts. Comparisons of life-history traits among the evolved lines of parasitoids did not reveal any evidence for costs of adaptation to H. defensa in terms of correlated responses that could constrain such adaptation. These results show that parasitoids readily evolve counter-adaptations to heritable defensive symbionts of their hosts, but that different symbiont strains impose different evolutionary challenges. The symbionts thus mediate the host-parasite interaction by inducing line-by-line genetic specificity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Invasive water hyacinth in Lake Victoria is being converted to compost formulations for crops. [•] Some water hyacinth compost formulations promote plant growth and nodulation. [•] Rhizobium and water hyacinth compost formulations affect plant infestation by aphids and anthracnose. [•] Synthetic fertilizer affects plant growth, nodulation, and pest infestation. [Copyright &y& Elsevier]

We identify and characterise α-amylases of the two aphid species, A. fabae and A. gossypi. To do this, α-amylases of the two insect species were extracted and their activities were determined using 1% soluble starch. Results showed that α-amylase, which hydrolyses starch, is present in both aphids. Also, it was shown that optimum pH and temperature for the α-amylases of both species is 7.0 and 40°C, respectively. Gel assays using zymogram analysis showed that in both aphid species more than one isoform (two isoforms) of α-amylases hydrolyszing carbohydrates are present. [ABSTRACT FROM AUTHOR]

The dynamics of predator-prey systems are strongly affected by the predators feeding rate on increasing prey density, that is, its functional response. Holling's assumptions concerning the biological process of handling time, that is, the time a predator spends on pursuing, subduing, eating, and digesting its prey, have been debated, as digestion represents a background component of predation. Therefore, predators are characterized either as digestion or handling limited. A study was initiated to identify the mechanism that limits the coccinellids' predation ability. The 14-spotted ladybird beetle, Propylea quatuordecimpunctata (L.) (Coleoptera: Coccinellidae), and its prey, Aphis fabae Scopoli (Hemiptera: Aphididae), were used in long- and short-term functional response experiments. Results showed that P. quatuordecimpunctata adults exhibit a type II functional response. The estimated attack rates and handling times differed significantly between long- and short-term experiments, indicating that the digestion process limits predation ability of P. quatuordecimpunctata. [ABSTRACT FROM AUTHOR]

This paper presents data referring the morphological characteristics and biometrical measurements of Aphis fabae, species captured from potato, carrots and tomatoes cultivations for a period of three years, from Didactic Station Timisoara and Varfurile, Arad county. The aphids have been collected with the yellow vessel traps on a two days. At Aphis fabae apterous adult have green-brown or black ovoid body and big marginal tubercles on prothorax and on abdominal segments I and VII; body length varies from 1.8 to 2.4 mm. Alatae aphid are more elongate with head and thorax shiny black; oviparous females with distinctly swollen hind tibiae and abdomen is black-green. The smallest length of the body established for aphids captured in West Zone of Romania was 1.40 mm, while the biggest was 2.20 mm. The average body length was 1.83 ± 0.20 mm. Regarding the length of the head and thorax, it may be noticed that the maximum length of these parts was 0.95 mm and minimum length was 0.50 mm. The average value calculated for the length of these parts was 0.77 ± 0.12 mm. The minimum width of head was 0.20 mm and the maximum width of head was 0.45 mm. The average value calculated for head width was 0.32 ± 0.05 mm. As far as the thorax width is concerned, this was minimum 0.40 mm and maximum 0.80 mm. Mean thorax width was 0.61 ± 0.02 mm the minimum length of the abdomen was 0.80 mm and minimum width was 0.50 mm, the maximum length of the abdomen was 1.40 mm and the maximum width was 1 mm. The mean length of the abdomen was 1.06 ± 0.12 mm, while the average value calculated for abdomen width was 0.79 ± 0.14 mm. In the existent literature, there is little information referring to biometric measurement and for these reasons, knowing the following aspect is of paramount importance. [ABSTRACT FROM AUTHOR]

Aphis fabaeScopoli (Hemiptera: Aphididae) is heteroecious and polyphagous that is harmful on secondary hosts such as many important agricultural products like beet, common bean, faba bean, potato and other products. This aphid is the cause of more than 33 viral transition. One of the mechanisms of plant resistance is antixenosis. This mechanism influences on placement and nutrition of pests that result in less damage. In this study, antixenosis resistance mechanism of 12 varieties of bean was tested. Experiment was on completely randomised design with 12 treatments and 6 replications. Bean varieties include of white bean, kidney bean and wax bean, and each replication includes one pot, and then, pots were placed under the isolated room that were filled with winged adult aphids in circular form. After 24 and 48 h, aphids and level of nymph production were counted. The lowest number of adult aphids was observed on Sayad variety among 12 varieties (during 24 h). The least number of produced nymphs was in Daneshkade variety. In Sayad variety, the frequency of matured insects and produced nymphs was minimum. [ABSTRACT FROM AUTHOR]