Psyllid Research Articles

Distribution and genetic diversity of five invasive pests of Eucalyptus in sub-Saharan Africa

Eucalyptus is one of the most planted tree genera across the world, but is heavily challenged by invasive insect pests originating from the native range of these trees. The rate of introduction of non-native Eucalyptus-feeding insects has increased globally, including in sub-Saharan Africa where Eucalyptus trees have an important socio-economic role. In this study, we mapped the distribution and examined the genetic diversity of non-native Eucalyptus insect pests in 14 countries across sub-Saharan Africa. We focused on five foliage-feeding insect pests of Eucalyptus which are known to be present in the region, namely the bluegum chalcid wasp, Leptocybe invasa; the redgum lerp psyllid, Glycaspis brimblecombei; the bronze bug, Thaumastocoris peregrinus; the Eucalyptus weevil, Gonipterus sp.n.2; and the Eucalyptus gall wasp, Ophelimus maskelli. Insect samples were collected through structured surveys and small-scale sampling which were both combined with published literature to determine the distribution of these insect pests. Genetic diversity of each of these insect pests was estimated/assessed based on mitochondrial cytochrome oxidase I (COI) or cytochrome b (Cyt b) sequence data. Except O. maskelli, which is a relatively recent arrival, the other insect pests were found broadly distributed across the sampled countries, with first reports in many countries. Analysis of genetic diversity confirmed a common origin of geographically distant populations for G. brimblecombei and O. maskelli, moderate diversity for T. peregrinus and Gonipterus sp.n.2 and at least two distinct lineages for L. invasa. Two divergent haplogroups of L. invasa, with overlapping geographic range were confirmed in Ghana, Malawi, Sierra Leone, South Africa and Zimbabwe. Compared to published literature, new haplotypes were detected for T. peregrinus, Gonipterus sp.n.2 and L. invasa, suggesting multiple introduction of those pests in the region. Results of this study will have implications for quarantine, management and future research of Eucalyptus insect pests in the region and beyond.

Plants Mineral Nutrition on the Preference of Glycaspis brimblecombei (Hemiptera: Aphalaridae) in Eucalyptus sp.

The plants nutritional maintenance is a support to their natural defense in relation to the insects attack of economic importance. The mineral nutrition arises as an alternative, since it provides the plants silvicultural conditions necessary to express all their productive potential, with the power of resistance to biotic constraints. Thus this study had as objective to evaluate the effect of different formulations of mineral fertilization in the eucalyptus plantations in relation to occurrence of Glycaspis brimblecombei (Moore), in the field. The experiment was carried out in the field from December 2015 to December 2016. The experimental arrangement was planned provided in the factorial design, with three origins of Eucalyptus sp. (Eucalyptus camaldulensis Dehn; hybrids (Eucalyptus urophylla S.T. Blake) x Eucalyptus grandis (Hill ex Maiden) and E. urophylla x E. camaldulensis); and seven nutritional formulations. The research data were subjected to analysis of variance (ANOVA), under a randomized block design in a factorial scheme (3 x 7), and the means compared by the Tukey test at 5% probability of error. The response variable used in the analysis was the occurrence of eggs and lerps, being transformed, in order to become suitable for parametric tests. The population fluctuation was carried out in the planting annual cycle. For the correlation analysis between the dependent and the independent variables, the data were analyzed by Pearson correlation (r) and their values were analyzed by using the Student's T-Test. The omissions influenced on the preference of the red gum lerp psyllid to Eucalyptus sp. In E. camaldulensis the omission of nitrogen and potassium influence on the preference and the absence of silicon causes the favoring of the pest oviposition. In the hybrid E. urophylla x E. grandis the absence of fertilization and the absence of nitrogen, phosphorus, potassium, individually, are less preferred.

PRELIMINARY RESULTS ON THE SPATIO-TEMPORAL VARIABILITY OF GLYCASPIS BRIMBLECOMBEI (HEMIPTERA PSYLLIDAE) POPULATIONS FROM A THREE-YEAR MONITORING PROGRAM IN SARDINIA (ITALY)

The red gum lerp psyllid Glycaspis brimblecombeiis an invasive insect species worldwide. Prolonged attacksby this psyllid may cause both direct and indirect damages to Eucalyptustrees, such as plant weakening, developmentalreductions and phylloptosis, resulting in death within 2-3 years. After the first report in Campania (Italy) in 2010 onEucalyptus camaldulensis trees, it quickly spread to all surrounding central-southern regions of Italy. In Sardinia, G.brimblecombeiwas first recorded in 2011, and is currently found throughout the island. From 2013 to 2015 amonitoring program was carried out in 11 locations throughout Sardinia in order to estimate the density pattern of bothits adults and preimaginal stages, as well as the general population trend of G. brimblecombeiover the years. Ananalysis of G. brimblecombei population abundance showed an almost stable level of infestation over the years, and aseasonal pattern with a population peak in the summer. However, an earlier peak of population abundance was detectedin 2015 compared to the previous years. A spatial heterogeneity of the level of infestation was observed throughout theisland, highlighting the potential effects of environmental conditions in regulating the populations of both G.brimblecombeiand its natural enemies.

ENVIRONMENTAL FACTORS IMPACT AND INCIDENCE OF PARASITISM OF PSYLLAEPHAGUS BLITEUS RIEK (HYMENOPTERA ENCYRTIDAE) ON POPULATIONS OF GLYCASPIS BRIMBLECOMBEI MOORE (HEMIPTERA APHALARIDAE) IN MEDITERRANEAN CLIMATIC AREAS

The red gum lerp psyllid, Glycaspis brimblecombeiMoore (Hemiptera, Aphalaridae), is an Australian native sap-sucking insect pest of eucalypts that has been first reported for the West Palaearctic Region in 2008 and, in 2010, it hasbeen found also in Italy. Subsequently its primary parasitoid, Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae),was also detected within the main European and North African infested areas, where no release of the parasitoid was everperformed. This study, carried out in 30 Eucalyptus camaldulensis plantations located along the coast, on the hills andthe mountains in Mediterranean climatic areas of Sicily (Italy), aimed to determine the influence of environmentalparameters on the incidence of both, the psyllid infestation level and the parasitization activity. P. bliteusreached high-est average levels in summer samplings and resulted widespread in Sicily at all detected altitudes without statisticallysignificant differences. P. bliteus parasitization is the main factor lowering G. brimblecombei infestation; this result,together with the accidental and contemporaneous arrival of the host and its parasitoid, could explain the absence of highdamage level on eucalypts in Sicily. The most significant metric factors positively influencing G. brimblecombei infes-tation are the percentage of daily hours above 80% of relative humidity and the average maximum temperature, obvi-ously related to other, but less significant climatic factors. The altitude affects both infestation and parasitization, but sin-gle sites could explain significantly more, so that the local conditions where the samplings were carried out have to beconsidered as the main responsibles for the variability in the obtained results. In any sampled Sicilian site, from sea levelto 540 m a.s.l., both the psyllid and its parasitoids show a good adaptation to climatic conditions, confirming that areasfitting for E. camaldulensisgrowth fit also for P. bliteus activity, and proving that Mediterranean climate, differently fromsome inland areas of California, does not obstacle its parasitic activity.

Effect of the eucalypt lerp psyllid Glycaspis brimblecombei on adult feeding, oviposition‐site selection, and offspring performance of the bronze bug, Thaumastocoris peregrinus

AbstractOviposition‐site selection may be greatly affected by competitive plant‐mediated interactions between phytophagous insects but these interactions have been poorly investigated on trees. Here, we evaluated the potential interaction between two invasive pests of Eucalyptus trees, the red gum lerp psyllid, Glycaspis brimblecombeiMoore (Hemiptera, Sternorrhyncha: Aphalaridae), and the bronze bug, Thaumastocoris peregrinusCarpintero et Dellapé (Heteroptera: Thaumastocoridae). We assessed the effect of the co‐occurrence of G. brimblecombei on the selection of feeding and oviposition sites by T. peregrinus females using dual‐choice bioassays. We compared developmental time and survival of the first instar of nymphs reared on healthy Eucalyptus tereticornisSmith (Myrtaceae) leaves and on leaves infested with the lerp psyllid, either with or without lerps (i.e., white conical sweet‐tasting structures, secreted during the nymphal stage). Bronze bug females prefer to oviposit on lerp‐carrying leaves but we found no difference in feeding preference when compared to healthy leaves. Infestation with the lerp psyllid hampered nymphal performance in terms of developmental time and survival, although the presence of lerps reverted the effect in survival and shortened the duration of the initial instar. These results display an interaction between these two insect species that affects both the oviposition preference of T. peregrinus females and the nymphal performance. Although there seems to be a discrepancy between mother preference and offspring performance, feeding on the lerps may prove beneficial to the offspring under long‐term conditions and multiple infestation by other pests and diseases.

Glycaspis brimblecombei (Hemiptera: Psyllidae) attack patterns on different Eucalyptus genotypes

BackgroundThe red gum lerp psyllid, Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), an eucalypt insect pest from Australia, was reported in Brazil in 2003. This study evaluated damage patterns of this pest on Eucalyptus camaldulensis Dehn (Myrtaceae) and its hybrids E. urophylla X E. camaldulensis (urocam) and E. urophylla X E. grandis (urograndis). In addition, parasitism rates of Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) on G. brimblecombei collected on different eucalypt genotypes are reported.MethodsPlantation plots of three eucalypt genotypes were evaluated over one year. The eucalypt leaves were collected and examined for attack by G. brimblecombei. Nymph parasitism of G. brimblecombei by P. bliteus was recorded.ResultsDamage by G. brimblecombei was lower on the hybrid genotypes and on the adaxial surface of the eucalypt leaves. G. brimblecombei egg and nymph density were negatively correlated with monthly rainfall. Nymph parasitism of G. brimblecombei by P. bliteus was low (2.9%) independent of genotype and did not vary throughout the year.DiscussionOur data indicate the use of less susceptible eucalypt genotypes (e.g., hybrids) as an alternative to G. brimblecombei management. Because of the current low mortality rates for G. brimblecombei resulting from P. bliteus parasitism, biological control with this natural enemy is not recommended as a management strategy for G. brimblecombei.

Development of Glycaspis brimblecombeiMoore (Hemiptera: Aphalaridae) on Eucalyptus camaldulensisDehnh. and Eucalyptus dunniiMaiden

Abstract The red gum lerp psyllid Glycaspis brimblecombei is an invasive insect species, native from Australia, that specifically feeds on Eucalyptus trees. It has invaded several countries throughout the world. In Argentina, it was first recorded in 2005, although little is known about its ecology in the region. We assessed G. brimblecombei population development on Eucalypus camaldulensis and Eucalyptus dunnii using samples of branches for the immature stages and yellow sticky traps for the adults. We also identified the meteorological variables associated with changes in the red gum lerp psyllid abundance. The abundance of eggs, nymphs and adults stages of G. brimblecombei was significantly greater on E. camaldulensis than on E. dunnii in the 2 years of the survey. Glycaspis brimblecombei development was complete on E. camaldulensis where all instars were present, even in the unfavourable seasons. The full development of the psyllid population was not observed in E. dunnii where a high mortality of the first and second nymphal instars was detected. Temperature and relative humidity were the variables that mostly affected red gum lerp psyllid abundance, whereas no effect of rainfall was detected.

Eucalypt-feeding psyllids use colour to locate the choicest leaves: what looks good must also be good

Eucalypt-feeding psyllids use colour to locate the choicest leaves: what looks good must also be good

APPLE PROLIFERATION DISEASE IN CROATIAN ORCHARDS: A MOLECULAR CHARACTERIZATION OF ‘CANDIDATUS PHYTOPLASMA MALI’

Apple proliferation (AP) causes major economic losses to the European apple industry. The causal agent associated with AP is ‘Candidatus Phytoplasma mali’ which belongs to the same phylogenetic cluster as two other fruit tree phytoplasmas: ‘Ca. P. pyri’ and ‘Ca. P. prunorum’. ‘Ca. P. pyri’ and ‘Ca. P. solani’ have sporadically been associated with symptomatic apples in Croatia in previous surveys. There was no molecular evidence of ‘Ca. P. mali’ presence until the start of this study, when it was confirmed for the first time. In this four-year survey (2011-2014), the detection and characterization of ‘Ca. P. mali’ from apples and psyllid vectors was carried out. Detection was based on PCR-RFLP analysis of the 16S rRNA gene. Real-time PCR was also used for amplifying ‘Ca. P. mali’ 16S rDNA and Malus domestica chloroplast tRNA leucine gene. Phylogenetic analysis of 16S rDNA and aceF gene sequences confirmed the identification of selected phytoplasma strains. Considerable aceF variability among the strains was detected, and a new, yet unrecorded aceF genotype was found. ‘Ca. P. mali’ has consistently been identified with high incidence in apple samples from Croatian continental region orchards, whereas it occurred sporadically in the coastal areas. This is the first molecular detection and characterization of ‘Ca. P. mali’ strains from both apple (Malus domestica Burkh.) and psyllid vector Cacopsylla picta (Forster) in Croatia.

Emerging pests and diseases threaten Eucalyptus camaldulensis plantations in Sardinia, Italy

The rapid growth and environmental adaptability of Eucalyptus species has favored their global cultivation for pulpwood production. On the island of Sardinia, Italy, eucalypt plantations were established in the 20th century primarily in areas reclaimed from marshland, but the trees are now grown all over the island as ornamentals or windbreaks, and for timber, pulp and honey production. In recent years, an unusual decline and mortality of unknown etiology has been observed in Eucalyptus camaldulensis (river red gum) plantations throughout the island. Given the ecological and economic importance of eucalypt ecosystems in Sardinia, a survey was carried out in 2013 to determine which insect pests and fungal pathogens are directly involved in these phenomena. Field surveys throughout the island revealed severe infestations with the red gum lerp psyllid (Glycaspis brimblecombei) at all 12 surveyed sites, with the greatest numbers of pre-imaginal stages and adults occurring between May and July. The adult population reached its peak in July, followed 2 months later by the peak population of its specific parasitoid, Psyllaephagus bliteus. Symptoms of leaf chlorosis, crown thinning, shoot and branch dieback, sunken cankers, epicormic shoots and exudations of kino gum were also observed at the 12 field sites. Symptomatic woody samples yielded fungal isolates representing three distinct families: Botryosphaeriaceae, Diaporthaceae and Valsaceae. Morphological and DNA sequence data revealed seven distinct fungal species, namely Diaporthe foeniculina, Neofusicoccum australe, N. luteum, N. mediterraneum, N. parvum, N. vitifusiforme and Valsa fabianae. Two putative new species of Cytospora were also identified. Neofusicoccum australe was the only species recovered from all 12 sites, with isolation frequencies of 51-95%. Pathogenicity trials revealed that all Neofusicoccum species except N. vitifusiforme are directly involved in the etiology of the observed decline in the E. camaldulensis population on Sardinia.

Effect of silicon application to Eucalyptus camaldulensis on the population of Glycaspis brimblecombei (Hemiptera: Aphalaridae)

The use of silicon in forestry has increased recently as it is directly related to improved resistance to insect pests. The red gum lerp psyllid, Glycaspis brimblecombei , occurs in all eucalypt producing regions in Brazil. Two field experiments were conducted to study the effect of silicon applied to Eucalyptus camaldulensis on the psyllid population. In the first experiment, the applications were made via soil (calcium silicate) and leaves (potassium silicate) in a nine months old E . camaldulensis plantation. In the second experiment, we evaluated silicon on seedlings, incorporating it into the substrate (soil) or applying it on leaves (foliar). Monthly, for 24 months, the number of psyllid eggs and immatures were counted on leaf samples. The plant height was measured at 9, 12, 16 and 24 months (experiment 1) and at 4, 8, 12 and 24 months (experiment 2) after application. The numbers of eggs and immatures were lower in periods of higher precipitation, indicating less psyllid attack during the rainy season. The psyllid population was lower in treatments with application of silicon both foliar and via soil compared to control. No significant differences were found in the height of E . camaldulensis plants.

Contrasting effects of habitat management on different feeding guilds of herbivorous insects in cacao agroforestry systems

Human pressure on natural habitats increases the importance of agroforests for biodiversity conservation. The objective of this study was to evaluate the role of cacao traditional cultivation system (CTCS) on the conservation of the herbivorous insect community when compared with a monodominant rubber agroforest, a type of agricultural system for cacao cultivation. The insects were sampled in three habitats in Southeastern Bahia, Brazil: native forests, CTCS and rubber agroforests. In each habitat, 18 plots of 10 m2 were established, and the structural measures were collected and herbivorous insects were sampled with a Malaise/window trap. The diversity of folivorous decreased with the simplification of vegetation structure, but species composition was similar among habitats. In addition to a decrease in the availability of resources in monodominant rubber agroforests, the latex present in these systems have limited the occurrence of species that cannot circumvent latex toxicity. The diversity of sap-sucking insects was similar among habitats, but species composition was similar only in the CTCS and native forest, and it was different in the rubber agroforest. We observed turnover and a higher frequency of individuals of the family Psyllidae in the rubber agroforest. The biology and behavior of Psyllids and absence of natural enemies enable their diversity to increase when they are adapted to a new host. We observed a shift in the composition of xylophagous insects in the rubber agroforest compared to that in other habitats. Moreover, this agroforest has low species richness, but high individual abundance. Latex extraction is likely an important additional source of volatile compounds discharged into the environment, and it increases the attraction and recruitment of coleoborers to these sites. We concluded that CTCS has an herbivorous insect community with a structure similar to the community found in native forests of the region, and they present a more interesting conservation strategy when compared to rubber agroforests. We also emphasized the potential risk of local pest outbreaks in rubber agroforests for both the rubber and associated cacao trees.

First report of the presence of haplotypes A and B of Candidatus Liberibacter solanacearum in chili (Capsicum annuum L.) in the central region of Mexico.

Candidatus Liberibacter solanacearum (Lso) is a vector-borne Gram negative bacterium, limited to the phloem of infected plants of the families Solanaceae in America and New Zealand and Apiaceae in Europe. This bacterium has genetic variants denominated as five haplotypes A, B, C, D and E in different crops and regions. In Mexico, it is reported that haplotype B is associated with potato whereas only Lso A infects chili pepper in the northern region of Mexico. Due to this pathogen’s potential to cause damage in crops of economic importance in Mexico, the objective of this study was to check whether different Lso variants could be found in chili infected by this bacterium. In 2012 and 2013, psyllids (vector) and chili (cv. Rivera) samples were collected from commercial production fields in Yurecuaro, Michoacan (central Mexico). Samples were also collected of psyllids and symptomatic potato plants in Toluca, Mexico. DNA was extracted from tissues of the plants and the psyllids with appropriate protocols. The DNA samples were tested for the presence of Lso by PCR using 16-23S rDNA primers and for Lso haplotypes using SSR (LSO- SSR- 1F and LSO- SSR- 1R). We found that in natural environments haplotype A occurred more frequently in chili than in potato. To our knowledge, this is the first report of haplotypes A and B from Lso associated with variegated chili in Mexico.

CRYPTIC HAPLOTYPES OF “CANDIDATUS LIBERIBACTER AFRICANUS”

“Candidatus Liberibacter africanus” (Laf) has long been recognised as a causal agent of the devastating citrus disease huanglongbing (HLB) or citrus greening. This species is currently restricted to Africa, the Arabian Peninsula and some Indian Ocean islands and is vectored by the African citrus psyllid, Trioza erytreae. Blotchy mottle on citrus leaves is characteristic of the disease. Somewhat similar symptoms in the rutaceous tree Calodendrum capensis (Cape chestnut) resulted in the discovery of Laf outside commercial citrus crops in South Africa. This was classed as a subspecies of Laf (capensis, hence LafC). In subsequent surveys of commercial citrus crops and Calodendrum, both natural and ornamental specimens, LafC was not found in citrus, nor has Laf been found in C. capensis. HLB was reported from Madagascar in 1968 but no sequences from this source have so far been published. Until fairly recently, only the reference 16S rRNA gene sequences of Laf (L22533) and LafC (AF137368) had been deposited in GenBank. Both of these reference sequences contain a number of unresolved nucleotides. When these nucleotide positions are invstigated by aligning against more recently available sequences, it becomes evident that these unresolved positions represent one percentage point difference in similarity between Laf and LafC. The originally reported 97.4% similarity is therefore incorrect based on this new information. Recalculating the similarity on the full length 16S rDNA sequence results in 99.54% similarity, a value too high to justify a subspecies status. LafC should therefore be downgraded as a haplotype of Laf. Further, the six 16S rRNA gene sequences currently available in GenBank identified as Laf as a species separate into two haplotype groups. The three haplotypes of Laf are therefore: (i) LafA, designated as the first accession sequenced (L22533); (ii) LafC, i.e the former subspecies “capensis”, to recognise the priority in the use of this term; (iii) LafB, the third previously unrecognised haplotype. Thus the cryptic presence of three haplotypes is revealed by this review of the Laf 16S rDNA sequences.

First record of two invasive eucalypt psyllids (Hemiptera: Psylloidea) in Israel

Two eucalypt-feeding psyllids (Hemiptera: Psylloidea: Aphalaridae): the eucalypt shoot psyllid, Blastopsylla occidentalis Taylor and the red gum lerp psyllid, Glycaspis brimblecombei Moore are reported from Israel for the first time. Both species belong to Spondyliaspidinae, a subfamily of jumping plant lice that feed generally on Myrtaceae, mainly eucalypts. The psyllids were collected from Eucalyptus camaldulensis Dehnh., a dominant eucalypt species in Israel. A summary ofthe globaldistributionand the host trees of the two psyllids are provided and their potential threat to eucalypts in Israel is discussed. Diagnostic information to distinguish between the two psyllids is presented, with an identification key for the adults of six eucalypt-feeding psyllid species in the Western Palearc- tic region.

The jumping plant-lice (Hemiptera: Psylloidea) of Belarus

A checklist of the known psyllids of Belarus is given: 12 species (one of them doubtful) have been previously reported and 43 species are added here, bringing the number of confirmed species to 54. The psylloid fauna of the country remains poorly known. Based on information from surrounding countries, another 73 species can be expected. An illustrated identification key is provided for the 127 species whose occurence in Belarus has been confirmed or is likely.

First record of Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), in Turkey

In this study, the occurrence of Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) was recorded for the first time on Eucalyptus camaldulensis (Myrtaceae) leaves in Turkey. In addition the generalist predator Anthocoris nemoralis Fabricius (Hemiptera: Anthocoridae) and the parasitoid of the red gum lerp psyllid Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) were also found as natural enemies. P. bliteus is also for the first time recorded in Turkey.

Glycaspis brimblecombei Moore, 1964 (Hemiptera: Psyllidae) on eucalyptus: oviposition non-preference and antibiosis

Forest plantations with Eucalyptus spp. (L’ Her) in Brazil are highly yielding. However, this activity is more and more threatened due to interactions with phytophagous insects, especially by exotic species, such as the red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae). This study aimed to evaluate the resistance in eucalyptus against the psyllid in oviposition and biological development assays, attempting to identify potential genotypes resistant to the pest for forest plantations. In addition, we tested the hypothesis of that concentration of total phenolics and lignin, and amount of epicuticular wax were associated with the expression of resistance. Results showed that there was variation in the levels of resistance among the genotypes assessed. Oviposition non-preference was observed on Eucalyptus citriodora (Hook) in free-choice and no-choice tests, and Clone FP10 was least preferred in the no-choice test. The genotypes E. citriodora and Clone FP6 provided 100 % nymphal mortality, and Clones FP7 and FP9 also affected negatively the G. brimblecombei development by lengthening the duration of the nymphal stage and reducing adult emergence. Clone FP6 had higher concentration of total phenolics and larger contact angle formed between the water droplet and leaf surface, which may be associated with thicker layer of epicuticular wax on the leaves, and one of the causes of high nymphal mortality. Thus, the use of the resistant genotypes of eucalyptus screened against G. brimblecombei is a promising and viable alternative for forest plantations infested with this pest.

Biological control of Glycaspis brimblecombei (Hemiptera: Aphalaridae) in eucalyptus plantations

The genus Eucalyptus, native to Australia, is the host of psylloid insects such as the red gum lerp psyllid Glycaspis brimblecombei, a major Eucalyptus pest introduced into Brazil among other countries. The encyrtid Psyllaephagus bliteus is a primary parasitoid used in the biological control of G. brimblecombei .T his study aimed to determine the parasitism of G. brimblecombei by P. bliteus released in eucalyptus plantations. Investigations were carried out in a 19-ha eucalyptus plantation comprised of 9-year-old Eucalyptus camaldulensis (Myrtaceae) in the munici- pality of Luiz Antonio, Sao Paulo State, Brazil. Twenty P. bliteus pairs were released at five points in the study area between May and September 2006 and 2007 ap- proximatelyevery20days.Forevaluationofparasitism, ten leaves per twig were randomly selected and unpar- asitized nymphs of G. brimblecombei ,m ummies (parasitized nymphs of G. brimblecombei) and empty mummies (after emergence of P. bliteus adults) were counted on their abaxial and adaxial parts before and after each release of P. bliteus. The parasitism rates of G. brimblecombei in 2006 and 2007 were 0.21-5.92% and 0.28-7.03% in the control; these values rose to 28.28-78.57%and30.32-79.34%,respectively,inareas involved in parasitoid release. Parasitism levels of G. brimblecombei nymphs in areas with P. bliteus re- lease were affected by the environmental temperature, which is discussed as a potential limitation to the estab- lishment of this parasitoid and to its effectiveness as a biological control agent.

Use of FTA Technology to ExtractWheat streak mosaic virusandCandidatusLiberibacter Solanacearum from Single Vectors

Detection and quantification of plant pathogens is a fundamental component of plant disease epidemiology. For vector-borne diseases, pathogen detection and quantification within the vector is often necessary to understand development and spread of disease. However, extraction and testing of pathogens from a single vector can be expensive and tedious, especially with large numbers of samples. Therefore, to simplify sample collection and reduce cost of analysis, we used a new nucleic acid elution approach using existing Flinders Technology Associates (FTA) technology from Whatman GE Healthcare. We applied this method in two very distinct vector-borne pathogen systems for Wheat streak mosaic virus (Tritimovirus) (McKinney 1937) and Candidatus Liberibacter solanacearum (Liefting et al. 2009). Total DNA and RNA were extracted from adult and nymphal psyllids (family Psyllidae) and wheat curl mite, Aceria tosichella Keifer, respectively using FTA cards (Whatman GE Health care, Pittsburgh, PA), and results were compared to extraction with DNeasy/RNeasy® kits (Qiagen Inc., Valencia, CA). Additionally, composite samples of multiple mite and psyllid vectors were used to compare the efficiencies of both methods. FTA elution and kit extractions were significantly different (P < 0.001). Slightly lower cycle threshold (Ct) values of 27.8 ± 0.19 and 25.5 ± 0.17 and 29.8 ± 0.09 and 27.45 ± 0.05 were determined for the composite adult and nymphal psyllids for the FTA and kit extractions, respectively. Wheat curl mite Ct values averaged 32.5 ± 0.75 and 27.6 ± 1.5 for the FTA elution and kit extractions, respectively. Coefficient of variation values were found to be lower for the FTA elution method when compared to the kit extractions for both the adult and nymphal psyllid (0.7 and 0.9%) and wheat curl mite (2.3 and 5.5%). Despite lower Ct values the FTA elution method is more cost efficient, protects nucleic acid integrity, and proved to be a valuable and reliable tool for detection and comparative studies of both pathogens within a single-vector sample.