Rate of consumption,biological parameters,and population growth capacity of <Emphasis Type="Italic">Orius laevigatus</Emphasis> fed on <Emphasis Type="Italic">Spodoptera exigua</Emphasis>

Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is already successfully used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in protected crops. In the present work, the predatory capacity of O. laevigatus on the eggs and larvae of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) as well as the population growth capacity of O. laevigatus fed on eggs of the noctuid were determined. Fourth and 5th instar nymphs had a greater consumption of eggs than younger ones. Females consumed more eggs than males. Only 5th instar nymphs and adults preyed on the neonatal larvae of S. exigua. The intrinsic rate of natural increase did not differ between O. laevigatus fed with S. exigua eggs and those offered eggs of the substitute host Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). Thus, O. laevigatus is a good candidate for the biological control of S. exigua, a cosmopolitan pest of many crops.     

Reproductive tables of predatory phytoseiid mites (<Emphasis Type="Italic">Phytoseiulus persimilis,Galendromus occidentalis</Emphasis>, and <Emphasis Type="Italic">Neoseiulus cucumeris</Emphasis>)

Feeding of predatory mites (Phytoseiulus persimilis, Galendromus occidentalis, and Neoseiulus cucumeris) on different life stages of Tetranychus atlanticus under optimal conditions was studied. Daily and total consumption of prey by predators and selection of prey of different life stages were studied for 5 days and for the entire feeding period. Average daily food consumption [number of individuals] for the entire life period of mature mite females constituted 0.43 females + 5.0 [nymphs and males] + 3.4 eggs of Tetranychus atlanticus in P. persimilis; 0.12 females + 3.70 [nymphs and males] + 3.10 eggs in G. occidentalis; and 0.19 females + 4.10 [nymphs and males] + 3.50 eggs in N. cucumeris. During the entire period of feeding, P. persimilis preferred large individuals and at the postembryonic stages selected prey to a greater extent than G. occidentalis and N. cucumeris (61.8 and 55.1%, respectively). The use of a 5-day express-method is possible for estimation of some biological characteristics of phytoseiids that previously consumed the same food for a long period. In other cases, analysis of characteristics for the entire life period is necessary.     

Biology of a Neotropical Harlequin Stink Bug, <Emphasis Type="Italic">Runibia perspicua</Emphasis> (F.)

Laboratory and field studies were conducted with nymphs and adults of the Neotropical stink bug Runibia perspicua (F.) to evaluate their biology on plants. Total nymph mortality was ca. 13% on immature fruits of Brunfelsia australis Benth. (IFBA) and 90% on raw shelled peanuts, Arachis hypogaea L. (RSP); no nymphs survived on immature pods of green bean, Phaseolus vulgaris L., or on immature fruits of privet, Ligustrum lucidum Ait. Nymph developmental time was ca. 36 on IFBA and 55 days on RSP. Body weight was significantly greater when nymphs were raised isolated compared to those raised in groups. Adult feeding activity was greater than third instars on IFBA. Adult longevity on IFBA + cherry tomato, Solanum lycopersicum L. fruit, reached ca. 150 days. On IFBA, fecundity was 2.5 egg masses/female and 48.3 eggs/female; 25.6% of the eggs hatched. Adults did not reproduce on tomato. Body weight gain did not increase significantly for both sexes during the first four weeks of adult life on IFBA. In the field, plants of B. australis were surveyed in Passo Fundo, RS (28°15′S; 52°24′W). The majority of egg masses were deposited on the lower (abaxial) surface of leaves. Nymphs aggregated on immature fruits, and adults were seldom found on the plants. These are the first data on the performance of R. perspicua on B. australis indicating that this plant species is suitable to the bug’s biology.     

Host suitability of the Mediterranean flour moth for rearing <Emphasis Type="Italic">Meteorus pulchricornis</Emphasis> (Hymenoptera: Braconidae), a polyphagous endoparasitoid of pest lepidopteran larvae

We investigated the host suitability of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) for a polyphagous koinobiont endoparasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), a common natural enemy of various pest lepidopteran larvae. The estimated probability of adult wasp emergence was 80% or higher when eggs were laid in nearly fully grown larvae of E. kuehniella (fresh weight, >?20.0 mg). The body size of emerged adult wasps increased with the initial weight of the host larvae at oviposition. The fresh weight of adult wasps reared on E. kuehniella was approximately 60% of that when reared on a natural host Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), and the lifetime fecundity of wasps reared on E. kuehniella was approximately half of that when reared on S. litura. Ephestia kuehniella was shown to be a positive host candidate for the mass rearing of M. pulchricornis, but further investigation is needed to increase the body size of wasps for more practical use of this species as a biocontrol agent.     

The brine shrimp Artemia sp. as alternative prey for rearing the predatory bug Macrolophus caliginosus

The predatory bug Macrolophus caliginosus, which is widely used in greenhouse crops, is limited in its application by its high price. An important factor in the cost is the high price of Ephestia kuehniella eggs, the prey used in their mass rearing. In order to reduce their price, alternatives to moth eggs are currently being investigated. The brine shrimp Artemia sp. is produced in large quantities in saline lakes and is fed as live food source to the larvae of a variety of marine and freshwater organisms. In this study, we tested Artemia sp. as prey for rearing M. caliginosus from two strains. We evaluated developmental and reproduction parameters of the predator when fed nauplii, enriched nauplii with a fatty acid, dry cysts and hydrated cysts, and were compared with those obtained when the predator was fed with E. kuehniella eggs. Nauplii had a significant reduction in survivorship, a delay in development of nymphs and a low reproduction of adults. Nauplii enriched with docosahexaenoic acid (DHA, 22:6n − 3), a common practice for larviculture of some marine fish species, resulted toxic to M. caliginosus nymphs and survival was quite low. On the contrary, either dry or hydrated cysts from the two strains tested of the brine shrimp produced the same nymphal survivorship, nymphal development time and weight and fecundity of adults as those obtained with E. kuehniella eggs. Demographic parameters of the eighth generation of the predator reared with cysts of the two strains, either dry or hydrated, were as good as those of moth eggs. We concluded that Artemia sp. cysts were a good substitution prey for the mass rearing of M. caliginosus.     

Effects of crop type on persistence and control efficacy of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> against the two spotted spider mite

The influence of five different crops (beans, cucumber, eggplant, maize, and tomato) on persistence and the control efficacy of Beauveria bassiana (Balsamo) Vuillemin to Tetranychus urticae Koch was investigated. Plants were artificially infested with T. urticae. B. bassiana conidia were suspended in Break-thru^® solution (0.01%) at three different concentrations (0.5, 1, 2 g l^?1) and sprayed once onto plants. Plants in the control treatment were sprayed with Break-thru^® solution alone. The number of conidia and levels of mite mortality were evaluated. Colony forming unit counts of conidia recovered from plant leaves declined over time regardless of the concentrations of B. bassiana applied. The rate of decline was different among crops and significantly higher on maize. However, more than 50% of the initial population of conidia were still viable on crops three weeks after application. The longer persistence of B. bassiana on crops did not result in better control of mites. Rather, mortality was positively correlated to the amount of inoculum deposited on leaves immediately after spraying. Mortality of mites was concentration-dependent and influenced by the host crop, with less control observed on maize and tomato than eggplant, beans and cucumber. Results were consistent between trials conducted and confirmed the hypothesis that the type of crop can influence the efficacy of B. bassiana against T. urticae.     

Experience of plant infestation by the omnivorous arthropod <Emphasis Type="Italic">Nesidiocoris tenuis</Emphasis> affects its subsequent responses to prey-infested plant volatiles

Nesidiocoris tenuis, an omnivorous arthropod, infests plants in either the absence or presence of prey arthropods. We studied whether plant-infestation experience of N. tenuis affected its subsequent prey-finding behavior. We used sesame plants and eggplants as food plants for N. tenuis, and common cutworm (CCW) (Spodoptera litura larvae) as prey. We focused on their olfactory response to CCW-infested sesame plants versus CCW-infested eggplants in a Y-tube olfactometer. When N. tenuis adults experienced the infestation of sesame plants for one day, they preferred volatiles from CCW-infested sesame plants to those from CCW-infested eggplants. By contrast, when N. tenuis experienced the infestation of eggplants for one day, they showed no difference in their preference between the two odor sources. When the duration of the infestation of plants was increased to four days, N. tenuis that had experienced sesame plants showed a reversed response: they preferred CCW-infested eggplant volatiles, while those that had infested eggplants again showed no difference in their preference. Next, we studied the olfactory preference of N. tenuis that had previously infested plants with moth (Ephestia kuehniella) eggs. We found that irrespective of plant species and of duration of experience (either one or four days), N. tenuis adults that had previously experienced one plant species showed a significant preference for volatiles from CCW-infested plants of the same species. The blends of the volatiles emitted from CCW-infested sesame plants and those from CCW-infested eggplants were qualitatively different. Possibility to control the olfactory response of N. tenuis to certain prey-infested plant volatiles by adjusting their feeding history is discussed.     

Immature stages of <Emphasis Type="Italic">Molipteryx fuliginosa</Emphasis> (Uhler) (Heteroptera,Coreidae) in the South of the Russian Far East

The morphology of the egg and the I-V-instar nymphs of Molipteryx fuliginosa (Uhler) was studied based on the observations made under near-natural conditions in Primorskii Territory since the emergence of over-wintered adults till the appearance of adults of the new generation, including egg production, maturation and molt at each nymphal instar. The egg and the nymphal instars are described and the distinguishing characters of Molipteryx fuliginosa and Coreus marginatus (Linnaeus) are given.     

Functional characterization of the powdery mildew susceptibility gene <Emphasis Type="Italic">SmMLO1</Emphasis> in eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis> L.)

Eggplant (Solanum melongena L.) is one of the most important vegetables among the Solanaceae and can be a host to fungal species causing powdery mildew (PM) disease. Specific homologs of the plant Mildew Locus O (MLO) gene family are PM susceptibility factors, as their loss of function results in a recessive form of resistance known as mlo resistance. In a previous work, we isolated the eggplant MLO homolog SmMLO1. SmMLO1 is closely related to MLO susceptibility genes characterized in other plant species. However, it displays a peculiar non-synonymous substitution that leads to a T → M amino acid change at protein position 422, in correspondence of the MLO calmodulin-binding domain. In this study, we performed the functional characterization of SmMLO1. Transgenic overexpression of SmMLO1 in a tomato mlo mutant compromised resistance to the tomato PM pathogen Oidium neolycopersici, thus indicating that SmMLO1 is a PM susceptibility factor in eggplant. PM susceptibility was also restored by the transgenic expression of a synthetic gene, named s-SmMLO1, encoding a protein identical to SmMLO1, except for the presence of T at position 422. This indicates that the T → M polymorphism does not affect the protein role as PM susceptibility factor. Overall, the results of this work are of interest for the functional characterization of MLO proteins and the introduction of PM resistance in eggplant using reverse genetics.     

Impact of Chemical,Organic and Bio-Fertilizers Application on Bell Pepper, <Emphasis Type="Italic">Capsicum annuum</Emphasis> L. and Biological Parameters of <Emphasis Type="Italic">Myzus persicae</Emphasis> (Sulzer) (Hem.: Aphididae)

Myzus persicae (Sulzer) is a polyphagous aphid that causes chlorosis, necrosis, stunting, and reduce growth rate of the host plants. In this research, the effects of Zinc sulfate and vermicompost (30%), Bacillus subtilis, Pseudomonas fluorescens, Glomus intraradices, G. intraradices × B. subtilis, and G. intraradices × P. fluorescens compared to control was investigated on the growth characters of Capsicum annuum L. and biological parameters of M. persicae. Different fertilizers caused a significant effect on growth characters of C. annuum and biological parameters of M. persicae. The highest plant growth was observed on Zinc sulfate and B. subtilis treated plants, and the lowest was on control. Increase in the amount of specific leaf area (SLA) (0.502 mm² mg^?1) was significantly higher in the B. subtilis than other fertilizer treatments. The longest (10.3 days) and the shortest (5.3 days) developmental times of M. persicae nymphs were observed on 30% vermicompost and Zinc sulfate treatments, respectively. The lowest adult longevity periods of M. persicae (11.2 and 11.3 days) were observed on G. intraradices × B. subtilis and 30% vermicompost treatments, respectively, and the longest ones (16.4 days) on Zinc sulfate. The highest rate of nymphal mortality and the lowest amount of nymphal growth index (NGI) were recorded on 30% vermicompost. The nymphs reared on Zinc sulfate treatment had the lowest rate of nymphal mortality and the highest amount of NGI. Thus, amending the soil with 30% vermicompost had a significantly negative effect on the biological parameters of M. persicae that can be used as an ecological control tactic for this pest.     

Development,Reproduction, Survival,and Demographic Patterns of <Emphasis Type="Italic">Tuta absoluta</Emphasis> (Meyrick) (Lepidoptera: Gelechiidae) on Different Commercial Tomato Cultivars

The increase in the production of tomato, Solanum lycopersicon Mill. (Solanaceae), has favored the proliferation of pests, especially Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). In this study, the development, reproduction, survival, and demographic parameters of T. absoluta reared on six commercial tomato cultivars (Cherry, Cordilheira, Giuliana, Nemoneta, Paron, and Santa Clara) were evaluated. Tuta absoluta completed its development in all tomato cultivars. Development from newly hatched caterpillar to newly emerged adult varied between 24.8 and 28.2 days. Female fecundity ranged from 126.3 to 166.9 eggs, with fertility from 54.2 to 84.1%. Mortality during egg-adult development varied between 21.4 and 46.4% for insects reared on cultivars Cherry and Giuliana, respectively. The cultivars Cordilheira, Giuliana, and Santa Clara are promising options to tomato producers in order to decrease the attack and proliferation of T. absoluta. However, the development and population growth of T. absoluta is faster on the tomato cultivar Cherry.     

Identification of extremely halophilic archaea associated with adult <Emphasis Type="Italic">Artemia urmiana</Emphasis>

The brine shrimp, Artemia is the dominant macrozooplankton present in many hypersaline environments. Artemia urmiana is the only macroscopic organism in Urmia Salt Lake (Iran), and the high salinity of the lake makes it a suitable environment for halophilic archaea too. Because of common environment for Artemia and extreme halophiles; this investigation is concentrated on studying the relationship between Artemia and halophilic archaea in Urmia Lake. In this study first the procedure of arhaea isolation was done. Then, isolated strains were sub-cultured and DNA was extracted and amplified by PCR using specific primers for amplifying archaeal 16S rRNA. The amplified archeal DNA fragments were purified, and sequenced. 16S rRNA sequences were compared to known sequences using the NCBI BLAST program. Sequences relating to Halorubrum, Haloarcula and Halobacterium species were identified in Urmia Salt Lake water and Artemia adults and the phylogenetic tree of different species was constructed. Only Halorubrum species were present in association with Artemia. They belong to Halobacteriaceae family of archeae which are isolated from different salt lakes in different parts of world and we could show their existence in adult Artemia, another organism living in hypersaline enviroments.     

Population development of the predatory mite <Emphasis Type="Italic">Amblydromalus limonicus</Emphasis> is modulated by habitat dispersion,diet and density of conspecifics

Habitat dispersion, diet and density can influence the per capita population growth of predators, and dispersed habitat can provide a spatial refuge that reduces the possibility of cannibalism among predators, thereby increasing their realized population growth rate. We tested the influence of variable habitat dispersion (dispersed patches, general patches and aggregated patches), two diets (Typha orientalis pollen and Ephestia kuehniella eggs) and initial predator density—one or two Amblydromalus limonicus (Garman and McGregor) (Acari: Phytoseiidae) founder females—on the population growth of A. limonicus in 7 days. Dispersed patches resulted in a higher total number of A. limonicus than the other two types of habitat dispersion from days 3–7 when fed on either of the diets, and started with either one or two A. limonicus females. Compared with E. kuehniella eggs, T. orientalis pollen resulted in more A. limonicus regardless of one or two founder females. Compared with two founder females, beginning with one founder female on pollen produced significantly more predatory mite females in dispersed and aggregated patches. A four-way ANOVA showed that the main effects indicated that habitat, diet, density, and time significantly influenced the number of immature and female A. limonicus. Significant interactions between habitat dispersion and diet were detected on immature and female A. limonicus. Our findings suggest that increasing the dispersion of artificial shelters on crop leaves may stimulate the control efficiency of predators in greenhouses. Furthermore, T. orientalis pollen provides a high nutritional quality supplemental diet that could enhance the ability of A. limonicus to control pests.     

Humic Fertilizer and Vermicompost Applied to the Soil Can Positively Affect Population Growth Parameters of <Emphasis Type="Italic">Trichogramma brassicae</Emphasis> (Hymenoptera: Trichogrammatidae) on Eggs of <Emphasis Type="Italic">Tuta absoluta</Emphasis> (Lepidoptera: Gelechiidae)

The tomato leaf miner, Tuta absoluta (Meyrick), is a devastating pest of tomato worldwide. One of the control measures of T. absoluta is the use of biological control agents, such as Trichogramma wasps. Interactions between natural enemies and insect pests may be affected by application of fertilizers, because changes in plant quality through the fertilizer application may therefore affect herbivore characteristics and suitability of them to parasitism. Laboratory tests were carried out to evaluate the life table parameters of Trichogramma brassicae Bezdenko on T. absoluta eggs reared on tomato plants treated either with vermicompost (40%), humic fertilizer (2 g/kg soil), or control (suitable mixture of field soil and sand). Population growth parameters of T. brassicae were affected by fertilizer treatments. Significant differences were found for immature life period and total fecundity of T. brassicae on the treatments. Differences of intrinsic rate of natural increase (r _m), finite rate of increase (λ), net reproductive rate (R ₀), mean generation time (T), and doubling time (DT) of T. brassicae among treatments were also significant. The lowest values of r _m, λ, and R ₀ were recorded for T. brassicae developed on T. absoluta eggs on control treatment, whereas the highest values of these parameters were observed on 2 g/kg humic fertilizer. Furthermore, T. brassicae had the shortest T and DT values on 2 g/kg humic fertilizer and 40% vermicompost treatments. Our results showed that application of humic fertilizer and vermicompost could positively affect population growth parameters of T. brassicae on eggs of T. absoluta fed on tomato plants.     

Development of <Emphasis Type="Italic">Cleruchoides noackae</Emphasis>, an egg-parasitoid of <Emphasis Type="Italic">Thaumastocoris peregrinus</Emphasis>, in eggs laid on different substrates,with different ages and post-cold storage

Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae) is an egg parasitoid of Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae). The parasitism and development of C. noackae was studied in T. peregrinus eggs of different ages, laid on eucalyptus leaves or paper towel and stored at 5 °C. The emergence, sex ratio and development of C. noackae and hatched nymphs of T. peregrinus were evaluated. This parasitoid had an emergence rate higher than 60% from zero to one, one to two, and two to three-day old eggs and lower than 10% for those 3–4 and 4–5 days old. The female proportion was 78% and the egg-adult period for C. noackae was 19.5 days. The use of T. peregrinus eggs up to three days old, laid on paper towel and stored at 5 °C for 14 days did not affect the biological parameters of C. nockae and should be used for mass rearing of this parasitoid.     

Ticks collected on birds in the state of São Paulo,Brazil

The present study reports a collection of Amblyomma spp. ticks in birds from several areas of the state of São Paulo, Brazil. A total of 568 tick specimens (404 larvae, 164 nymphs) were collected from 261 bird specimens. From these ticks, 204 (36%) specimens (94 larvae, 110 nymphs) were reared to the adult stage, being identified as Amblyomma longirostre (94 larvae, 90 nymphs), Amblyomma calcaratum (13 nymphs), Amblyomma nodosum (2 nymphs), and Amblyomma cajennense (5 nymphs). Additionally, 39 larvae reared to the nymphal stage and 8 nymphs that died before reaching the adult stage were identified as A. longirostre according to peculiar characters inherent to the nymphal stage of this species: scutum elongate, and hypostome pointed. The remaining 271 larvae and 46 nymphs were identified as Amblyomma sp. Ticks were collected from 51 species of birds distributed in 22 bird families and 6 orders. The order Passeriformes constituted the vast majority of the records, comprising 253 (97%) out of the 261 infested birds. Subadults of A. longirostre were identified from 35 species of Passeriformes, comprising 11 families (Cardinalidae, Dendrocolaptidae, Fringillidae, Furnariidae, Parulidae, Pipridae, Thamnophilidae, Thraupidae, Turdidae, Tyrannidae, and Vireonidae), and from 1 species of a non-passerine bird, a puffbird (Bucconidae). Subadults of A. calcaratum were identified from 5 species of Passeriformes, comprising 5 families (Cardinalinae, Conopophagidae, Pipridae, Thamnophilidae and Turdidae). Subadults of A. nodosum were identified from 2 species of Passeriformes, comprising two bird families (Thamnophilidae and Pipridae). Subadults of A. cajennense were identified from 2 species of non-passerine birds, belonging to 2 different orders (Ciconiiformes: Threskiornithidae, and Gruiformes: Cariamidae). Birds were usually infested by few ticks (mean infestation of 2.2 ticks per bird; range: 1–16). Currently, 82 bird species are known to be infested by immature stages of A. longirostre, with the vast majority [74 (90%)] being Passeriformes. Our results showed that Passeriformes seems to be primary hosts for subadult stages of A. longirostre, A. calcaratum, and A. nodosum. However, arboreal passerine birds seem to be the most important hosts for A. longirostre whereas ground-feeding passerine birds seem to be the most important for both A. calcaratum and A. nodosum. In contrast, the parasitism of birds by subadults of A. cajennense has been restricted to non-passerine birds.     

MiR395 Overexpression Increases Eggplant Sensibility to <Emphasis Type="Italic">Verticillium dahliae</Emphasis> Infection

Verticillium wilt (V. wilt), a notorious wilt disease caused by Verticillium dahliae, often leads to the reduction of eggplant (Solanum melongena L.) production. MiRNAs, as a class of small RNAs, can regulate gene expression and then affect growth and development in plants. MiR395 has been proven to respond to sulfate-deficient stress in Arabidopsis thaliana and sulfate is well known to have a close relationship with plant disease resistance. To explore the function of eggplant miR395, we examined its expression in V. dahliae-infected eggplant by qRT-PCR and found miR395 exhibited a gradual reduction trend with time after infection. We then expressed pre-miR395 from Arabidopsis thaliana in Suqi eggplant and resistance analysis showed that miR395 overexpressed plants were hypersensitive to V. dahliae infection. We further measured the content of GSH and activities of POD and SOD and the results indicated that the index of GSH/POD/SOD in the overexpressed plants was lower than that of the wild-type control under V. dahliae infection. These results suggest that miR395 plays a negative role in eggplant response to V. dahliae infection.     

Soybean aphid, <Emphasis Type="Italic">Aphis glycines</Emphasis> (Hemiptera: Aphididae), developmental and reproductive capacity on white clover, <Emphasis Type="Italic">Trifolium repens</Emphasis> (Rosales: Leguminosae), in northeast China

Nymphs of Aphis glycines Matsumura were individually reared to adults in the laboratory on detached leaf discs of Trifolium repens L. (white clover) mounted on agar medium. Adults of A. glycines were fed T. repens within small clip cages in the field. Development, reproduction and intrinsic rates of increase of A. glycines were studied. These data were compared to those of controls fed known host plants including cultivated soybean Glycine max (L.) Merr. and the wild soybean species Glycine soja Sieb & Zucc. The results demonstrated that nymphs of A. glycines successfully developed into adults and reproduced efficiently when reared on T. repens in the laboratory. The lower development temperature threshold for nymphs fed T. repens was estimated as 8.27 °C, and the effective cumulative temperature for A. glycines development from nymph to adult was 90.91 degree-days. Adults of A. glycines could also survive on T. repens in the field, but only a few nymphs were produced.     

Aseptic rearing procedure for the stinkbug <Emphasis Type="Italic">Plautia stali</Emphasis> (Hemiptera: Pentatomidae) by sterilizing food-derived bacterial contaminants

The stinkbug Plautia stali Scott is a notorious agricultural pest whose posterior midgut hosts specific bacteria essential for its growth and survival, highlighted as an experimental model for symbiosis studies. Some symbiotic bacteria of P. stali are cultivable, found free-living in and acquired from the environment, and, furthermore, some free-living environmental bacteria are potentially capable of establishing symbiotic association with P. stali. In this context, it is expected that such environmental bacteria may occasionally contaminate and infect the experimental insects maintained in the laboratory, which could potentially affect the functional analyses of the symbiosis. Here we report that such contamination events do occur under a laboratory rearing conditions for P. stali. When symbiont-deprived newborn nymphs from surface-sterilized eggs were reared in sterilized plastic containers with autoclaved water, most of them died as nymphs presumably as a result of aposymbiosis, but only a small fraction could attain adulthood and the adult insects were all infected with γ-proteobacteria allied to Pantoea and Enterobacter. A variety of bacteria, mainly Bacillus and also Pantoea and Enterobacter, were detected from peanuts and soybeans provided as food for P. stali. Autoclaving of peanuts and soybeans eradicated these bacteria but negatively affected the host survival, whereas ethanol sterilization of peanuts and soybeans removed Pantoea and Enterobacter, but not Bacillus, without negative effects on the host survival. On the basis of these results, we established a practical procedure for aseptic rearing of P. stali, which will enable reliable and strict analyses of host–symbiont interactions in the model symbiotic system.