Comparative demography of Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) on deciduous fruit.

Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann) are highly polyphagous fruit fly species and important pests of commercial fruit in regions of the world where they are present. In South Africa, B. dorsalis is now established in the north and northeastern parts of the country. B. dorsalis is currently absent in other parts of the country including the Western Cape Province which is an important area for the production of deciduous fruit. C. capitata is widespread in South Africa and is the dominant pest of deciduous fruit. The demographic parameters of B. dorsalis and C. capitata on four deciduous fruit types Prunus persica (L.) Batsch, Prunus domestica L., Malus domestica Borkh. and Pyrus communis L. were studied to aid in predicting the potential population establishment and growth of B. dorsalis in a deciduous fruit growing environment. All deciduous fruit types tested were suitable for population persistence of both B. dorsalis and C. capitata. Development was fastest and survival highest on nectarine for both species. B. dorsalis adults generally lived longer than those of C. capitata, irrespective of the fruit types that they developed from. B. dorsalis had a higher net reproductive rate (Ro) on all deciduous fruit tested compared to C. capitata. However, the intrinsic rate of population increase was estimated to be higher for C. capitata than for B. dorsalis on all fruit types tested primarily due to C. capitata's faster generation time. Provided abiotic conditions are optimal, B. dorsalis would be able to establish and grow in deciduous fruit growing areas.

Larval species composition and genetic structures of Carposina sasakii, Grapholita dimorpha, and Grapholita molesta from Korea.

Rapid determination of the larval species composition and understanding of their genetic structure is important to establish the appropriate management system for multiple species infesting in fruits. We established accurate and rapid diagnostic methods based on multiplex polymerase chain reaction (PCR) diagnostic techniques to discriminate the three major lepidopteran species in orchard, Carposina sasakii, Grapholita dimorpha, and Grapholita molesta. Each species was identified by amplifying species-specific PCR products (375 bp for C. sasakii, 125 and 234 bp for G. dimorpha, and 125 bp for G. molesta). Based on species composition analysis from six types of infested fruits, G. dimorpha constituted the highest proportion (47.8%), followed by 35.2 and 13.5% for G. molesta and C. sasakii, respectively. Interestingly, high prevalence was found in G. dimorpha and G. molesta for plum and peach, respectively. Based on genetic diversity analysis, the three insect species exhibited moderate or high haplotype diversity and low nucleotide diversity, ranging from 0.319 to 0.699 and 0.0006 to 0.0045, respectively. Demographic expansion was not detected according to either a neutrality test or mismatch distribution analysis. Moreover, no significant genetic structure corresponding to province, host plant, fruit type, or collection period was observed. These results suggest that the population of each species would have high dispersal ability following fruit-generating periods via intrinsic host adaptation ability regardless of the spatial and temporal conditions. Determination of larval composition on fruit is valuable for establishing appropriate management systems that take the species into consideration; additionally, population genetic approaches can be utilized to understand the effects of environmental factors (province, host fruit, fruit type, etc.) on population structures.

A new species of eriophyoid mite (Acari: Trombidiformes: Eriophyoidea) on Chaenomeles x superba (Frahm) Rehder (Rosaceae).

A new species, Epitrimerus chaenomeli n. sp., is described and illustrated in this paper. The description is based on the morphology of protogynes, deutogynes and nymphs. This new species was recorded on Chaenomeles x superba (Frahm) Rehder and its cultivar Crimson and Gold (Rosaceae) which have not previously been noted as a host for eriophyoid mites. Mites of this species caused slight rusting on the under-surfaces of infested leaf blades. In addition, a list of all known species of Epitrimerus found on Rosaceae is also provided.

Development of Anastrepha fraterculus (Diptera: Tephritidae) Related to the Phenology of Blueberry, Blackberry, Strawberry Guava, and Surinam Cherry Fruits.

Anastrepha fraterculus (Wiedemann, 1830) is the main pest of temperate climate orcharding. The study investigated the development of A. fraterculus related to phenological stage of blueberry, blackberry, strawberry guava, and Surinam cherry trees. The phenological stages I (green fruits), II (intermediate ripening stage of fruits), and III (fruits close to harvesting) were determined, and they are from 8th, 10th, and 11th week; 6th, 8th, and 9th week; 8th, 13th, and 16th week; and 5th, 6th, and 7th week after the first flowering of blueberry, blackberry, strawberry guava, and Surinam cherry trees, respectively. We collected fruits from orchards to determine the infestation index using the formula: number of pupa/fruit weight. To investigate the development of A. fraterculus, we determined the following biological parameters: egg-to-adult period, weight of pupae, oviposition period, fecundity, number of pupae, and number of infested fruits. The infestation index for the fruits collected in the field was greater in strawberry guava and Surinam cherry fruits. In the laboratory, the development of A. fraterculus occurred in stage III of blueberry. In blackberry, besides stage III, we also observed the development in stage II, however, at lower infestation. In strawberry guava, the development of A. fraterulus occurred in stages II and III, and the development in both stages was similar. For Surinam cherry, the development occurred in the three phenological stages with similar values for biological parameters. Overall, of the four hosts studied, the strawberry guava and Surinam cherry fruits allowed a better biological development of A. fraterculus, corroborating its preference for fruits native to Brazil.

A global phylogeny of leafmining Ectoedemia moths (Lepidoptera: Nepticulidae): exploring host plant family shifts and allopatry as drivers of speciation.

BACKGROUND: Host association patterns in Ectoedemia (Lepidoptera: Nepticulidae) are also encountered in other insect groups with intimate plant relationships, including a high degree of monophagy, a preference for ecologically dominant plant families (e.g. Fagaceae, Rosaceae, Salicaceae, and Betulaceae) and a tendency for related insect species to feed on related host plant species. The evolutionary processes underlying these patterns are only partly understood, we therefore assessed the role of allopatry and host plant family shifts in speciation within Ectoedemia. METHODOLOGY: Six nuclear and mitochondrial DNA markers with a total aligned length of 3692 base pairs were used to infer phylogenetic relationships among 92 species belonging to the subgenus Ectoedemia of the genus Ectoedemia, representing a thorough taxon sampling with a global coverage. The results support monophyletic species groups that are congruent with published findings based on morphology. We used the obtained phylogeny to explore host plant family association and geographical distribution to investigate if host shifts and allopatry have been instrumental in the speciation of these leafmining insects. SIGNIFICANCE: We found that, even though most species within species groups commonly feed on plants from one family, shifts to a distantly related host family have occasionally occurred throughout the phylogeny and such shifts are most commonly observed towards Betulaceae. The largest radiations have occurred within species groups that feed on Fagaceae, Rosaceae, and Salicaceae. Most species are restricted to one of the seven global biogeographic regions, but within species groups representatives are commonly found in different biogeographic regions. Although we find general patterns with regard to host use and biogeography, there are differences between clades that suggest that different drivers of speciation, and perhaps drivers that we did not examine, have shaped diversity patterns in different clades.

Control of pome and stone fruit virus diseases.

Many different systemic pathogens, including viruses, affect pome and stone fruits causing diseases with adverse effects in orchards worldwide. The significance of diseases caused by these pathogens on tree health and fruit shape and quality has resulted in the imposition of control measures both nationally and internationally. Control measures depend on the identification of diseases and their etiological agents. Diagnosis is the most important aspect of controlling fruit plant viruses. Early detection of viruses in fruit trees or in the propagative material is a prerequisite for their control and to guarantee a sustainable agriculture. Many quarantine programs are in place to reduce spread of viruses among countries during international exchange of germplasm. All these phytosanitary measures are overseen by governments based on agreements produced by international organizations. Also certification schemes applied to fruit trees allow the production of planting material of known variety and plant health status for local growers by controlling the propagation of pathogen-tested mother plants. They ensure to obtain propagative material not only free of "quarantine" organisms under the national legislation but also of important "nonquarantine" pathogens. The control of insect vectors plays an important role in the systemic diseases management, but it must be used together with other control measures as eradication of infected plants and use of certified propagation material. Apart from the control of the virus vector and the use of virus-free material, the development of virus-resistant cultivars appears to be the most effective approach to achieve control of plant viruses, especially for perennial crops that are more exposed to infection during their long life span. The use of resistant or tolerant cultivars and/or rootstocks could be potentially the most important aspect of virus disease management, especially in areas in which virus infections are endemic. The conventional breeding for virus-tolerant or resistant fruit tree cultivars using available germplasm is a long-term strategy, and the development and production of these cultivars may take decades, if successful. Genetic engineering allows the introduction of specific DNA sequences offering the opportunity to obtain existing fruit tree cultivars improved for the desired resistance trait. Unfortunately, genetic transformation of pome and stone fruits is still limited to few commercial genotypes. Research carried out and the new emerging biotechnological approaches to obtain fruit tree plants resistant or tolerant to viruses are discussed.

Development of a disease risk prediction model for downy mildew (Peronospora sparsa) in boysenberry.

Downy mildew caused by Peronospora sparsa has resulted in serious production losses in boysenberry (Rubus hybrid), blackberry (Rubus fruticosus), and rose (Rosa sp.) in New Zealand, Mexico, and the United States and the United Kingdom, respectively. Development of a model to predict downy mildew risk would facilitate development and implementation of a disease warning system for efficient fungicide spray application in the crops affected by this disease. Because detailed disease observation data were not available, a two-step approach was applied to develop an empirical risk prediction model for P. sparsa. To identify the weather patterns associated with a high incidence of downy mildew berry infections (dryberry disease) and derive parameters for the empirical model, classification and regression tree (CART) analysis was performed. Then, fuzzy sets were applied to develop a simple model to predict the disease risk based on the parameters derived from the CART analysis. High-risk seasons with a boysenberry downy mildew incidence >10% coincided with months when the number of hours per day with temperature of 15 to 20°C averaged >9.8 over the month and the number of days with rainfall in the month was >38.7%. The Fuzzy Peronospora Sparsa (FPS) model, developed using fuzzy sets, defined relationships among high-risk events, temperature, and rainfall conditions. In a validation study, the FPS model provided correct identification of both seasons with high downy mildew risk for boysenberry, blackberry, and rose and low risk in seasons when no disease was observed. As a result, the FPS model had a significant degree of agreement between predicted and observed risks of downy mildew for those crops (P = 0.002).

Herpetogramma bipunctalis (Lepidoptera: Crambidae) biology and techniques for rearing on leaves of the blackberry (Rubus spp., Rosaceae).

The larvae of the southern beet webworm Herpetogramma bipunctalis (Fabricius, 1794) damage the leaves of species in the plant genus Rubus. The present study investigated the biology of H. bipunctalis and developed a protocol for raising H. bipunctalis under laboratory conditions. On the basis of the biological data, we devised a life table. In order to develop the rearing procedures, we determined which oviposition substrate and blackberry cultivar were the most appropriate for larval development. The mean durations of the egg, larval, and pupal stages were 5.59 days, 26.37 days, and 13.37 days, respectively, and the corresponding survival rates were 80.83%, 49.07%, and 83.23%. The mean pupal weight was 0.0491 g for males and 0.0536 g for females. The mean life cycle (egg-to-adult) period was 45.33 days, and overall survival to adulthood was 33.01%. H. bipunctalis females laid a mean of 252.63 eggs over a mean of 13.60 days of oviposition; the mean pre-oviposition period was 2.67 days. Mean female and male life spans were 17.51 and 19.25 days, respectively, and the sex ratio was 0.51. The life-table data indicated that H. bipunctalis can reproduce 57.9 times per generation. Each cage contained one blackberry leaf placed on a paper towel. This method allowed us to obtain the greatest number of eggs. The larval stage was shorter for insects reared on leaves of the Guarani cultivar than for those reared on leaves of the Xavante cultivar (22.63 vs. 26.37 days). These basic data can aid in establishing strategies for the management of H. bipunctalis on blackberry farms.

Variation in selection and utilization of host crops in the field and laboratory by Drosophila suzukii Matsumara (Diptera: Drosophilidae), an invasive frugivore.

BACKGROUND: Drosophila suzukii, a pest of soft-skinned berries and stone fruits, has recently rapidly expanded its global range. The impacts of D. suzukii infestation and subsequent fruit damage in North America and Europe have been profound. The aim of the present work was to assess host selection of D. suzukii in the field and laboratory, with an emphasis on hosts commonly grown in the southeastern United States, where D. suzukii has been established since 2010. RESULTS: Raspberries were infested at a greater rate than blackberries in the field, and varieties within both species were infested at different rates. Primocane-fruiting blackberries were often the least heavily infested. Further, blackberries and raspberries grown under high tunnels were infested at lower rates than those grown outside. Fruit and artificial substrates with a lower surface penetration force were more heavily infested than firmer substrates in the laboratory; no eggs were laid in artificial substrates exceeding 52.00 cN surface penetration force. CONCLUSION: Infestation rates differ between species and varieties within species of Rubus in the southeastern United States. Fruit penetration force is one potential measure of host susceptibility, but host attractiveness will likely depend upon additional factors, such as soluble sugar content.

Herpetogramma bipunctalis (Lepidoptera: Crambidae) biology and techniques for rearing on leaves of the blackberry (Rubus spp., Rosaceae) / Biologia e técnica de criação de Herpetogramma bipunctalis (Lepidoptera: Crambidae) em folhas de amoreira-preta (Rubus spp., Rosaceae)

The larvae of the southern beet webworm Herpetogramma bipunctalis (Fabricius, 1794) damage the leaves of species in the plant genus Rubus. The present study investigated the biology of H. bipunctalis and developed a protocol for raising H. bipunctalis under laboratory conditions. On the basis of the biological data, we devised a life table. In order to develop the rearing procedures, we determined which oviposition substrate and blackberry cultivar were the most appropriate for larval development. The mean durations of the egg, larval, and pupal stages were 5.59 days, 26.37 days, and 13.37 days, respectively, and the corresponding survival rates were 80.83%, 49.07%, and 83.23%. The mean pupal weight was 0.0491 g for males and 0.0536 g for females. The mean life cycle (egg-to-adult) period was 45.33 days, and overall survival to adulthood was 33.01%. H. bipunctalis females laid a mean of 252.63 eggs over a mean of 13.60 days of oviposition; the mean pre-oviposition period was 2.67 days. Mean female and male life spans were 17.51 and 19.25 days, respectively, and the sex ratio was 0.51. The life-table data indicated that H. bipunctalis can reproduce 57.9 times per generation. Each cage contained one blackberry leaf placed on a paper towel. This method allowed us to obtain the greatest number of eggs. The larval stage was shorter for insects reared on leaves of the Guarani cultivar than for those reared on leaves of the Xavante cultivar (22.63 vs. 26.37 days). These basic data can aid in establishing strategies for the management of H. bipunctalis on blackberry farms.

Lagartas de Herpetogramma bipunctalis (Fabricius, 1794) causam danos nas folhas da amoreira-preta (Rubus spp.). O objetivo deste trabalho foi estudar sua biologia e desenvolver uma técnica de criação, em condições de laboratório. Com os dados de biologia, foi elaborada uma tabela de vida de fertilidade. Para o estudo da técnica de criação, foram determinados o substrato para obtenção de ovos e a cultivar de amoreira-preta mais adequada para o desenvolvimento larval. A duração dos estágios de ovo, lagarta e pupa foram de 5,59, 26,37 e 13,37 dias, com sobrevivência de 80,83, 49,07 e 83,23%, respectivamente. O peso das pupas foi 0,0491 g para machos e 0,0536 g para fêmeas. O ciclo biológico (ovo-adulto) foi de 45,33 dias, com sobrevivência total de 33,01%. As fêmeas colocaram, em média, 252,63 ovos durante 13,60 dias, com um período de pré-oviposição de 2,67 dias. A longevidade média de fêmeas e machos foi de 17,51 e 19,25 dias, respectivamente, e a razão sexual, de 0,51. Por meio da tabela de vida de fertilidade, determinou-se uma capacidade de aumento de 57,9 vezes a cada geração. Gaiolas revestidas com papel toalha e com a presença de folhas de amoreira-preta propiciaram a obtenção de uma maior quantidade de ovos. A duração do estágio larval para os insetos alimentados com folhas de amoreira-preta cv. Guarani (22,63 dias) foi menor do que aqueles alimentados com folhas da cv. Xavante (26,37 dias). Estas informações são básicas e auxiliarão em futuros estudos, visando ao estabelecimento de estratégias de manejo de H. bipunctalis em amoreira-preta.

Location of the mechanism of resistance to Amphorophora agathonica (Hemiptera: Aphididae) in red raspberry.

The aphid Amphorophora agathonica Hottes (Hemiptera: Aphididae) is an important virus vector in red (Rubus idaeus L.) and black (Rubus occidentalis L.) raspberries in North America. Raspberry resistance to A. agathonica in the form of a single dominant gene named Ag1 has been relied upon to help control aphid-transmitted plant viruses; however, the mechanism of resistance to the insect is poorly understood. Aphid feeding was monitored using an electrical penetration graph on the resistant red raspberry 'Tulameen' and compared with a susceptible control, 'Vintage'. There were no differences in pathway feeding behaviors of aphids as they moved toward the phloem. Once in the phloem, however, aphids feeding on resistant plants spent significantly more time salivating than on susceptible plants, and ingested significantly less phloem sap. This suggests that a mechanism for resistance to A. agathonica is located in the phloem. Reduced ingestion of phloem may result in inefficient acquisition of viruses and is a likely explanation for the lack of aphid-transmitted viruses in plantings of resistant cultivars.

Ability of the oriental fruit moth Grapholita molesta (Lepidoptera: Tortricidae) to detoxify juglone, the main secondary metabolite of the non-host plant walnut.

Many plant species produce toxic secondary metabolites that limit attacks by herbivorous insects, and may thereby constrain insect expansion to new hosts. Walnut is a host for the codling moth Cydia pomonella, which efficiently detoxifies the main walnut defensive compound juglone (5-hydroxy-1,4-naphthoquinone). The oriental fruit moth Grapholita molesta, which also belongs to the tribe Grapholitini, does not feed on walnut. We tested the performance of G. molesta, a highly invasive species, on artificial diets containing juglone at levels mimicking those found in walnut over the growing season. Juglone-fed G. molesta survived relatively well to adulthood, but larval and adult body weights were reduced, and larval developmental time was prolonged in a dose-dependent fashion. Chemical analysis of frass from larvae that had been fed a juglone-containing diet suggests that G. molesta reduces juglone to non-toxic 1,4,5-trihydroxynaphthalene in its gut. This unexpected tolerance of G. molesta to high levels of juglone may facilitate expansion of the host range beyond the current rosacean fruit trees used by this invasive pest.

The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens.

The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants.

Volatile organic compound emissions induced by the aphid Myzus persicae differ among resistant and susceptible peach cultivars and a wild relative.

Little is known on aphid-induced emissions of volatile organic compounds (VOCs) from trees and particularly on their intraspecific variability in association with resistance traits. We compared VOC emissions from five peach cultivars (Prunus persica (L.) Batsch) and a wild relative (Prunus davidiana (Carrière) Franch) that differ in their level (susceptible/resistant) and type (antixenosis, antibiosis) of resistance to the green peach aphid, Myzus persicae (Sulzer). Additionally, the kinetics of VOC induction in response to aphids was compared with that by mechanical wounding. Qualitative and overall quantitative differences among peach genotypes were found in VOC emissions that were mainly composed of methyl-salicylate, farnesenes, (E)-ß-ocimene and (E)-4,8-dimethyl-1,3,7-nonatriene. Irrespective of the type of resistance, all resistant genotypes had increased VOC emissions upon aphid attack, while in susceptible genotypes emissions remained low. Emission increases were highest in the genotypes that express increased aphid resistance during second infestations, which had also the highest proportions of methyl-salicylate in their emissions. VOC induction by aphids proceeded slowly with a delay of several hours. Artificial wounding of leaves did not result in emissions of aphid-induced VOCs but caused an immediate burst of green leaf volatiles and benzaldehyde. We conclude that VOC induction in resistant peach cultivars is part of a general defence syndrome that is being avoided or suppressed by M. persicae in the susceptible genotypes. The induction likely involves an aphid-specific elicitor and (methyl)-salicylate in the subsequent signalling and regulation processes that should include gene activation due to the marked delay in the emission response. The results are compared with those of the literature and discussed in view of their ecological and environmental significance.

Laboratory performance of two polyphagous invasive weevils on the predominant woody plant species of a northern hardwood community.

A complex of invasive weevils that consume roots as larvae and foliage as adults have become established in northern hardwood forests in North America. We evaluated adults of the two most prominent species, Phyllobius oblongus and Polydrusus sericeus, for longevity, foliage consumption, and egg production on several putative hosts commonly found in this ecosystem. Adult pairs were monitored in no-choice laboratory assays for the duration of their lifespans on basswood, Tilia americana, ironwood, Ostrya virginiana, sugar maple, Acer saccharum, raspberry, Rubus spp., or leatherwood, Dirca palustris. Overall, P. sericeus lived more than twice as long as P. oblongus and lived longer on all hosts. P. sericeus consumed more total leaf area than P. oblongus on basswood, ironwood, and raspberry, but P. oblongus had a higher leaf consumption rate on sugar maple. Basswood was a very good host for P. sericeus. Leatherwood was not a suitable host for either weevil species. The higher longevity and fecundity of P. sericeus than P. oblongus did not agree with that expected from population data, in that the latter species is substantially more abundant. This likely reflects P. oblongus ' superior performance on sugar maple, the dominant flora in the study area. These data provide a basis for estimating the broader impacts of adult weevil feeding.

Non-chemical control of leaf curling midges and sawflies in berries and currants.

The susceptibility of larvae of the leaf curling midge, Dasineura plicotrix, for entomopathogenic nematodes, predatory mites and rove beetles was studied in the laboratory. The results showed that the leaf curling midge larvae were unaffected by the nematodes Heterorhabditis bacteriophora, Steinernema carpocapsoe and S. feltiae. The predatory mite (Hypoaspis aculeifer) and the rove beetle (Atheta coriaria) were very effective in predating the larvae when continuously exposed. However, in a soil substrate the control of larvae was less successful. The vigorous burrowing behaviour of the larvae facilitates their escape from predators. This was enhanced by the formation of a cocoon consisting of soil and sand particles. The effects of the foliar fertilizer magnesium sulphate (bitter salt) were studied on gooseberry sawfty Nematus ribesii. The experiments showed that magnesium sulphate has a good residual action on eggs and neonate larvae. Also, an effect on the egg laying behaviour of the females was observed. The experiments showed that magnesium sulphate has a potential as a control agent for gooseberry sawflies.

Ecological studies on San José scale, Diaspidiotus perniciosus (Comstock) (Homoptera: Diaspididae) as a new insect pest on pear trees in Burg El-Arab area, Alexandria, Egypt.

The San José scale, D. perniciosus (Comstock) (Homoptera: Diaspididae) was noticed on pear trees all the year round in Burg El-Arab area (50 km West of Alexandria). Bio ecology and population fluctuations of this serious scale insect were carried out during the two subsequent seasons of September, 2004 until August, 2006. The calculated infestation rates (%) assured the presence of three peaks in both seasons. The estimated densities of fluctuating individuals of D. perniciosus on the inspected pear trees showed two distinctly prominent peaks, in addition to an overlapping one between them. It means, that the San Josè scale, D. perniciosus had three overlapping annual generations on pear trees in Burg El-Arab area under an irrigation system. The individuals of all stages could be found on trees all over the year. The population of the inspected immature stages; adult females and adult males were recorded and discussed as well as the parasitized individuals by the aphilinid parasitoid, Aphytis diaspidis (Howard) (Hymenoptera: Aphelinidae). The population density of the San José scale (SJS) reached its maximum during spring, folLowed by summer, winter, whereas the least percentage was recorded in autumn months. The obtained data showed also variable effects of the prevailing abiotic factors on the dynamical oscillation of (SJS) individuals. The daily mean temperature and the dew point were not the dominant efficient physical factors. On the contrary, it has been proved that there were either significant strong negative or positive relationships between daily relative humidity, wind speed, infestation rate, and population density of this studied insect pest.

Inheritance of Phytophthora root rot resistance in red raspberry determined by generation means and molecular linkage analysis.

Classical and molecular methodologies were used to determine the inheritance of Phytophthora root rot (PRR) resistance in red raspberry. The varieties 'Latham' and 'Titan,' resistant and susceptible, respectively, were used to create F(1), F(2), B(1), B(2), and S(1) populations for analysis. Generational means analysis was used to calculate the components of genetic variation and estimates of narrow and broad sense heritability for the plant disease index and the incidence of petiole lesions. The plant disease index showed additive genetic variation with additional significant interactions, but the incidence of petiole lesions was non-additive. A dominant, two-gene model was shown to be the best fit for the observed segregation ratios when classification for resistance was based on a combination of all criteria measured. Molecular linkage maps were generated from the segregating B(2) population. Linkage maps of both parents were constructed from amplified fragment length polymorphism (AFLP), Random amplified polymorphic DNA (RAPD), and uncharacterized resistant gene analog polymorphism (RGAP) markers with seven linkage groups each totaling 440 and 370 cM of genetic distance, respectively. An analysis of the distributional extremes of the B(2) population identified several RAPD markers clustered on two linkage groups associated with PRR resistance. QTL analysis identified two similar genomic regions on each map that explained significant percentages of phenotypic variation observed for the disease assessment criteria. Genetic mapping supports the dominant two-gene model developed from generational means analysis. The results reconcile conflicting reports on inheritance of PRR resistance, provide a basis for further investigation of durable resistance to Phytophthora caused diseases, and indicates that recurrent selection is the appropriate approach for the development of new resistant cultivars.

Mapping of A1 conferring resistance to the aphid Amphorophora idaei and dw (dwarfing habit) in red raspberry (Rubus idaeus L.) using AFLP and microsatellite markers.

BACKGROUND: Raspberry breeding programmes worldwide aim to produce improved cultivars to satisfy market demands and within these programmes there are many targets, including increased fruit quality, yield and season, and improved pest and disease resistance and plant habit. The large raspberry aphid, Amphorophora idaei, transmits four viruses and vector resistance is an objective in raspberry breeding. The development of molecular tools that discriminate between aphid resistance genes from different sources will allow the pyramiding of such genes and the development of raspberry varieties with superior pest resistance. We have raised a red raspberry (Rubus idaeus) F1 progeny from the cross 'Malling Jewel' x 'Malling Orion' (MJ x MO), which segregates for resistance to biotype 1 of the aphid Amphorophora idaei and for a second phenotypic trait, dwarf habit. These traits are controlled by single genes, denoted (A1) and (dw) respectively. RESULTS: The progeny of 94 seedlings was scored for the segregation of 95 AFLP and 22 SSR markers and a linkage map was constructed that covers a total genetic distance of 505 cM over seven linkage groups. The average linkage group length was 72.2 cM and there was an average of 17 markers per linkage group, of which at least two were codominant SSRs, allowing comparisons with previously published maps of raspberry. The two phenotypic traits, A1 and dw, mapped to linkage groups 3 and 6 respectively. CONCLUSION: The mapping of A1 will facilitate the discrimination of resistance genes from different sources and the pyramiding of aphid resistance genes in new raspberry cultivars; the mapping of dw will allow further investigations into the genetics of dwarfing habit in Rubus.

Counteracting selective regimes and host preference evolution in ecotypes of two species of walking-sticks.

The evolution of ecological specialization has been a central topic in ecology because specialized adaptations to divergent environments can result in reproductive isolation and facilitate speciation. However, the order in which different aspects of habitat adaptation and habitat preference evolve is unclear. Timema walking-stick insects feed and mate on the host plants on which they rest. Previous studies of T. cristinae ecotypes have documented divergent, host-specific selection from visual predators and the evolution of divergent host and mate preferences between populations using different host-plant species (Ceanothus or Adenostoma). Here we present new data that show that T. podura, a nonsister species of T. cristinae, has also formed ecotypes on these host genera and that in both species these ecotypes exhibit adaptive divergence in color-pattern and host preference. Color-pattern morphs exhibit survival trade-offs on different hosts due to differential predation. In contrast, fecundity trade-offs on different hosts do not occur in either species. Thus, host preference in both species has evolved before divergent physiological adaptation but in concert with morphological adaptations. Our results shed light onto which traits are involved in the initial stages of ecological specialization and ecologically based reproductive isolation.