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The black soldier fly (BSF) Hermetia illucens (L.) (Diptera: Stratiomyidae) has been recognized as a promising insect species for sustainable management of organic waste and by-products. Indoor breeding of BSF with artificial lighting has been proved successful, but efforts are still needed to optimize BSF reproductive output. Increasing adult density seems an option to exploit space, whereas decreasing artificial lighting duration may reduce unnecessary power consumption. This study aimed at investigating the effects of adult density (10, 25, and 50 pairs per 30 × 30 × 30 cm cage; i.e., 370, 926, and 1,852 pairs/m3), light regime (8:16, 12:12, and 16:8 [L:D] h), and their possible interactions, on some BSF life history traits relevant to reproduction. The results show that the overall BSF reproductive output increased with increasing adult density but was not affected by light regimes per se. With the highest BSF adult density tested, an average of more than 20,000 neonate larvae were produced from a cage within 10 d. At this density, increasing photoperiod increased neonate production, but also decreased the number of neonates per watt used for artificial illumination. The temporal oviposition patterns, mean individual female reproductive output, mating success, egg hatching rate, and insect survival rate were not affected by adult density or light regime as simple effects. However, the interaction between adult density and light regime was significant for the first oviposition peak, mean individual female reproductive output, and insect survival rate. The possible mechanisms behind our results are discussed.

The sap-sucking lace bug Gargaphia decoris Drake (Hemiptera: Tingidae) is a biological control agent released in New Zealand to control the invasive small tree or shrub Solanum mauritianum Scopoli (Solanaceae). The aim of this study was to investigate the effect of temperature, photoperiod and humidity on selected G. decoris life history traits. The selected traits were measured at six different temperatures (10, 15, 20, 25, 27.5 and 30 °C), three photoperiods (L:D 6:16, 14:10 and 16:8) and two relative humidity (RH) levels (50 and 70 ± 10%). Eggs and nymphs did not survive in the 10 °C and 30 °C treatments. The net reproductive rate (R0) resulted in population growth at all temperatures, but was highest at 25 °C. Egg hatch rate was highest at L:D 8:16, and nymphal and adult survival was better at L:D 16:8. Egg hatch was higher at 50 ± 10% RH and adult survival and population growth were higher at 70 ± 10% RH. These results will help to predict the persistence of established G. decoris populations and the potential for establishment at new release sites.

This study aimed to determine the suitability of several organic waste substrates to be processed by the larvae of the black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) (BSFL) in a value-added bioconversion system. Three types of organic waste (brewer's waste, solid phase of pig manure, and semidigested grass) were tested and compared with a standard larval diet, broll (wheat middling). Larval survival and growth, chemical composition of the resulting prepupae, conversion ratios of nutrients and waste dry matter, and waste reduction rate were measured. Larval survival was high in all tested substrates. Compared with the larvae fed pig manure or semidigested grass, those fed standard diet or brewer's waste showed shorter development time, higher weight gain, and higher prepupal crude protein and crude fat content. BSFL also reduce more dry matter in the standard diet or in brewer's waste than in the other two substrates. On the other hand, larvae fed semidigested grass took 70 d to complete development and suffered fat loss. Thus, we suggest that brewer's waste is the most suitable substrate among the selected wastes for being processed by BSFL, whereas semidigested grass is an unsuitable substrate. We found that lignin had a significantly negative effect on larval growth, and emphasized the importance of applying lignin-digesting microorganisms to lignin-rich substrates being converted by BSFL. Moreover, a protein:fat:digestible carbohydrate ratio of 2:1:2 was hypothesized to benefit larval development.

Phosphine (PH3) is used as an in-transit phytosanitary treatment (10-d fumigation period) for pine (Pinus radiata D.Don) logs exported from New Zealand to China. The ability of PH3 to penetrate through the bark of the logs is not well known. We designed equipment to accurately quantify PH3 penetration into the bark of wooden blocks (100 × 100 × 50 mm; n = 12) cut from the upper and lower trunk of recently harvested pine trees fumigated at 15 or 25 °C. Fumigations simulated commercial conditions consisting of two phases; phase I with 2.0 g m−3 of PH3 for the first 5 days (1–120 h) and 1.5 g m−3 of PH3 in phase II for the next 5 days (121–240 h). During the 10-d schedule, we achieved the required commercial CT (concentration × time) of ≥48,000 ppm h at both temperatures. Bark thickness (i.e., trunk location) did not significantly affect fumigant penetration. Phosphine penetration through the bark of the wooden blocks was greatest after each application, then the penetrated concentrations diminished over time. Greater penetration occurred at 15 °C than at 25 °C. Further studies are required to better understand the dynamics of PH3 penetration particularly at lower temperatures and through insect-infested blocks.

Background The Stakeholders in Methyl Bromide Reduction (STIMBR) are evaluating ethanedinitrile (EDN) as an alternative fumigant to methyl bromide for use as a phytosanitary treatment for pine logs (Pinus radiata D.Don). Ethanedinitrile is hypothesised to decompose into hydrogen cyanide (HCN) in the presence of water. This process, if it occurs, is of particular interest because it may influence the efficacy and emissions data needed for commercialisation. Methods The concentrations of EDN and HCN were measured in the treated space (28 L fumigation chambers) without (n = 1) and with pine log sections (n = 3; 46 ± 1.4% load factor) at 10 or 20 °C in a simulated commercial fumigation. Results On average, the cylinder of EDN tested contained 34.6 g m− 3 HCN (or 3.1%), which corresponds to a concentration of 0.8 g m− 3 (or 0.07%) in the treated space for a 50 g m− 3 EDN dose (commercial rate in Australia). This level of HCN is likely a result of the manufacturing process, whereby HCN is oxidised to produce EDN. During fumigation, HCN was detected in the treated space at relatively low concentrations, which did not significantly change over time. This indicates that HCN is not produced in substantial amounts during fumigation and that, as a result, insect efficacy is unlikely to be affected by low unchanging (P = 0.055) concentrations of this compound in the treated space. Conclusions The results of this work support the statement that EDN is not significantly converted to HCN during the treatment of recently harvested pine logs.

The lace bug, Gargaphia decoris Drake (Hemiptera: Tingidae) is a biological control agent of the South American invasive tree Solanum mauritianum Scopoli (Solanaceae). Gargaphia decoris has been established with some success in New Zealand and South Africa. In this study, we used the climatic modelling software CLIMEX (Hearne Scientific Software Pty Ltd, Australia) to assess how current and future climatic conditions might influence the geographic distribution of the biocontrol agent in these countries and worldwide. CLIMEX parameters were based on experimental data and calibrated with distribution records from the insect’s native and non-native range. In its native range, our model predicts that G. decoris could expand its distribution into northern coastal regions of Brazil, with tropical dry summer or monsoon climate. It could also expand beyond its native range into other countries with temperate and subtropical climates, as well as several regions with tropical savanna, equatorial and monsoon climate in coastal regions. In New Zealand the greatest potential for further expansion is within the North Island, and in South Africa the expansion is limited to mostly coastal areas. In a future climate change scenario (A1B, CSIRO Mk3 2090), there is a predicted reduced distribution globally, especially for Asia, Africa, and the Americas. In Europe the climatic suitability for G. decoris will increase, with an expanded potential distribution. In South Africa the potential distribution is predicted to slightly reduce, while an expansion is predicted into the colder regions of New Zealand. These models provide a useful tool to inform future releases of G. decoris and to guide monitoring efforts within and beyond release areas.

Larvae of the black soldier fly (BSF) Hermetia illucens (L.) (Diptera: Stratiomyidae) are promising organisms to be used for organic waste bioconversion. Breeding BSF indoors has been suggested as a cost-effective approach for countries with long winters or low sunlight levels through the year. As the BSF mating is visually mediated, artificial illumination conditions are critical to a successful indoor breeding system. In this study, we tested four different types of artificial light sources for their effects on BSF mating success. They included: (1) a halogen lamp; (2) a combination of a white light-emitting diode (LED) lamp and a fluorescent ultra violet lamp; (3) a metal halide lamp, and (4) a specially designed light-emitting diode (BSFLED) lamp, whose design was based on the specific BSF adult visual spectral sensitivity. We determined the spectra of four artificial light sources, compared their spectral composition in relation to the BSF-visible spectrum, and compared their effects on the mating success of two different BSF colonies. BSFLED was the most energy efficient light source in spectral composition and led to the highest mating success in terms of the percentage of inseminated females and fertile clutches. Thus, BSFLED is the most suitable light source tested in our experiment for breeding BSF indoors. The colony effect and possible light flickering effect on BSF mating success were also detected. The implications of these findings are discussed.

We report here the results of three successive toxicity studies against a selection of forest insect pests, conducted in New Zealand to determine the efficacy of reduced methyl bromide (MB) rates, i.e. rates lower than those currently used, to disinfest export pine logs. First, the relative tolerance to MB among the naked life stages of the golden-haired bark beetle, Hylurgus ligniperda, the black pine bark beetle, Hylastes ater (Coleoptera: Curculionidae) and burnt pine longhorn beetle, Arhopalus ferus (Coleoptera: Cerambycidae) was determined in the laboratory. Then, the most MB-tolerant species and life stage(s) in pine logs was subjected to selected fumigation schedules using reduced concentrations of MB. Finally, the results of the laboratory studies were validated under commercial conditions at the Port of Tauranga, New Zealand, using logs infested with the most tolerant life stage, and log stacks. Our results indicated that either 30 g/m3 MB at >15 °C or 40 g/m3 MB at ≤ 15 °C for 16 h would ensure quarantine security against forest insects in New Zealand export logs. These reduced MB concentrations are approximately 70% and 65%, respectively, lower than 80 g/m3 at >15 °C or 120 g/m3 at ≤15 °C. If implemented by regulatory agencies and accepted by trading partners, these concentrations will provide significant environmental and economic benefits to the New Zealand forest industry and will pave the way for other countries to implement similar approaches to reduce MB usage in accordance to the Montreal Protocol.

BACKGROUND The sorption and desorption characteristics of methyl bromide (MB) were determined during and after fumigation of recently harvested pine (Pinus radiata D. Don) logs. The effects of dose (48 or 120 g m-3 ), degree of bark cover (0, 50 or 100%) and end-grain sealing (sealed or unsealed) on sorption and desorption were determined over time. RESULTS Sorption of MB was proportional to the dose applied and dependent on the amount of end-grain sealed. After 16 h, an average of 70.7 ± 2.5% of the initial concentration remained in the treated space when end-grains were sealed, whereas only 47.3 ± 2.5% remained when unsealed. During aeration, MB was released from logs, initially ranging from 2.8 to 8.8 g · h m-3 , depending on the treatment. The rate of desorption quickly decreased during aeration. CONCLUSION The surface area of a log is the most important factor influencing MB sorption and desorption rates, with greater surface area resulting in greater (de)sorption rates. Sorption data can now be combined with insect toxicity data to estimate a minimum effective dose of MB for further evaluation, while desorption data can be combined with fumigant plume modelling to assess worker safety. © 2016 Society of Chemical Industry.

Sown flower strips are increasingly implemented within agri-environment schemes (AES) to increase functional biodiversity and ecosystem services such as pollination or natural pest control, but their effectiveness in achieving these goals remains poorly studied. We tested the performance of experimentally sown annual flower strips specifically designed to promote natural enemies of aphids and their pest control services (tailored flower strips) in adjacent potato crops (n = 8) compared with control fields (n = 10). Flower strips consisted of 11 plant species providing abundant floral and extra-floral resources. The abundance of key natural enemies of aphids (hoverflies, lacewings and ladybirds) and hoverfly species richness was greatly enhanced in tailored flower strips compared with potato control strips. This resulted in an average increase in the number of eggs deposited by hoverflies and lacewings by 127% and 48%, respectively, and a reduction in the number of aphids by 75% in adjacent potato crops. Synthesis and applications. We conclude that tailored flower strips can be an effective agri-environmental measure to enhance natural enemies and aphid control in nearby crops. Indeed, tailored flower strips may help to reduce insecticide input in potato production as they significantly decrease the probability that action thresholds are reached. Promoting natural enemy abundance and diversity, as observed for hoverflies, may increase the stability of pest control and provide additional benefits to agro-ecosystems in terms of natural enemy conservation. We thus recommend establishing tailored flower strips as a promising management option to reconcile the objectives of ecological intensification and biodiversity conservation.

We tested the efficacy of ethanedinitrile (EDN), a new fumigant considered as a potential methyl bromide (MB) replacement for the quarantine treatment of New Zealand pine, Pinus radiata D. Don, export logs. Firstly, toxicity trials were conducted in the laboratory with pine logs infested with the larvae, pupae, or adults of pine bark beetles, Hylurgus ligniperda and Hylastes ater, at 10 and 20 °C in 28-L chambers, to identify the most tolerant species and life stages. Then, logs infested with the most tolerant species and life stage were fumigated in 500-L laboratory chambers to determine whether the increase in the volume of the fumigated space and logs that will occur when scaling up from laboratory to commercial fumigations would affect EDN efficacy. Finally, confirmatory fumigation trials using commercial or semi-commercial sized log stacks, were conducted in a deforested commercial plantation area in Tokoroa, New Zealand, to demonstrate the efficacy of EDN in the field. Our results suggest EDN could be an effective alternative fumigant to MB for the phytosanitary treatment of logs exported from New Zealand. A phytosanitary fumigation schedule with EDN for P. radiata export logs that uses a concentration of 100 g/m3 for 20 h across a range of temperatures from 10 to 20 °C is recommended. Future efforts should focus on implementing the recommended schedule, under commercial practices, to provide quarantine security for export logs using EDN as a replacement for MB.

Brown marmorated stinkbug (BMSB), Halyomorpha halys (Stal), is an insect pest of concern to certain countries that import vehicles and shipping containers from the USA. Adult BMSB contained in gas-permeable cages were fumigated with sulfuryl fluoride in laboratory-scale chambers at 10.0 ± 0.5 °C ( x ¯ ± 2 s ), across a range of applied doses and treatment durations. Sulfuryl fluoride exposures, expressed as concentration (C) × time (t) products (Ct), were calculated, exposure-mortality regressions were modeled, and the relative contribution of C versus t toward treatment efficacy was evaluated relative to Haber’s Rule, specifically Czt = ω. The induction of diapause, to simulate overwintering physiology, resulted in an ∼ 2-fold increase in tolerance of adults toward sulfuryl fluoride, and this effect is more pronounced as the fumigation duration is shortened from 12 h. Results of this study identify how the applied dose and/or treatment duration can be modulated (i.e., tuned) to ensure adequate toxicological efficacy toward adult BMSB following a sulfuryl fluoride fumigation at air temperature ≥ 10.0 ± 0.5 °C ( x ¯ ± 2 s ). An assimilation of these technical results with labeling, environmental, and logistical considerations can be used to guide a fumigation schedule for operational implementation in the USA and beyond.

Planta, 237 (1), ISSN:0032-0935, ISSN:1432-2048

Journal of Chemical Ecology, 39 (5), ISSN:0098-0331, ISSN:1573-1561

Ethanedinitrile (EDN) has been identified as a possible alternative fumigant to methyl bromide (MB) as a phytosanitary treatment for New Zealand export logs A review of MB phytosanitary schedules has indicated that the treatment rates used in New Zealand may be able to be significantly reduced The toxicity of EDN was compared in the laboratory to that of reduced rates of MB using different life stages of the burnt pine longhorn beetle Arhopalus ferus Naked insects were fumigated with MB at 10C and 20C for 4 h or with EDN at the same temperatures for 3 h The mortalities achieved and the CT products calculated indicate that (1) a reduction in MB usage may be possible for the treatment of logs exported from New Zealand and that (2) EDN has potential as a phytosanitary alternative to MB for the treatment of logs

High sorption by Pinus radiata (D Don) logs may limit insecticidal efficacy of a fumigant by rapidly removing it from the treated headspace The sorption characteristics of a new fumigant ethanedinitrile (EDN) were quantified for recently harvested pine logs and the robustness of a proposed EDN sorption model developed for sawn timber was tested Over a 10h period average concentrations were 173 plusmn;1048724; 07 of the initial dose for logs with sealed ends and 94 1048724;plusmn; 04 for unsealed ends This is a high rate of sorption compared with other fumigants such as methyl bromide A proportional drop in headspace concentration over time was consistent for the two doses (20 and 50 g/m3) evaluated confirming that EDN sorption is influenced by the dose applied Bark cover did not significantly influence EDN sorption A revised sorption model for EDN is proposed here

The efficacy of ethanedinitrile (EDN, syn. cyanogen, EDN Fumigas®) for the control of burnt pine longhorn beetle (Arhopalus ferus (Mulsant)) adults was tested using a range of ethanedinitrile concentrations. The LD 99 for adults after a 3 h exposure at 15°C was 12.6 g/m 3 . The results demonstrate that ethanedinitrile is a potential phytosanitary alternative to methyl bromide for disinfesting burnt pine longhorn adults from sawn timber exported from New Zealand.

Elevated concentrations of atmospheric carbon dioxide (CO 2 ), a consequence of anthropogenic global change, may profoundly interfere with tritrophic interactions. Such effects with a focus on parasitoids as natural antagonists of herbivores have rarely been investigated. In particular, studies on effects of secondary metabolites induced by crop plant acclimation to elevated CO 2 on higher trophic levels were yet missing. We used the system composed of Brassica plants, the aphid Brevicoryne brassicae and the endoparasitoid Diaeretiella rapae , which is specialized on aphids feeding on brassicacean plants, to compare effects of elevated CO 2 (800 ppm) versus ambient CO 2 (400 ppm). Plants were exposed to the CO 2 concentrations for up to 10 weeks, aphids for 2–3 generations, and parasitoids for 1 generation, to allow for acclimation. Concomitant bioassays with herbivore-infested plants and parasitoids showed a significantly lower proportion of hosts parasitized under elevated compared to ambient CO 2 after a 10-week plant exposure. Parasitoid progeny emerged earlier but offspring adults were shorter lived. Plant glucosinolate concentrations were higher under elevated compared to ambient CO 2 , whereas, contrary to expectation, aphid glucosinolate concentrations were significantly lower. Likewise aphid body mass remained approximately 20% lower under elevated compared to ambient CO 2 . Thus, elevated CO 2 seems to have enhanced plant direct defense by an increase of natural plant defense compounds, however, it led to a decrease in indirect defense, likely due to the reduced host size. Our results point, for the first time, to a conflict between bottom-up and top-down control under elevated CO 2 .

A common characteristic of many invasive herbivorous insects is their ability to utilize a broad range of host plants. By using various hosts in phenological succession, multivoltine herbivores may increase the number of successful annual generations, at the same time as potentially increasing their overall fitness. To achieve such success, herbivores must be able to develop efficiently on the nutritional resources offered by their hosts. The oriental fruit moth Cydia (=Grapholita) molesta (Busck) (Lepidoptera: Tortricidae) is one of the most damaging invasive insect species. Peach (Prunus persica) is its primary host, whereas the pome fruits apple (Malus ×domestica Borkh) and pear (Pyrus communis) are considered as secondary hosts. In many parts of its geographical range, including southern Europe, populations of the moth switch from peach to apple or pear orchards during the growing season. The present study tests whether this temporal switch is supported by the physiological capability of the larvae with respect to developing efficiently on fruits of these taxonomically- related host plants. Larvae are reared on peach, apple or pear fruits; several life- history traits are measured; and correlations between the traits are calculated. The results obtained show that larvae do not have the same physiological capability with respect to using apple or pear fruits as hosts compared with using peach fruit. Pear fruit in particular is a sub-optimal diet. These findings suggest that, in the case of continuous geographical expansion, concomitantly with global warming, apple orchards might support oriental fruit moth populations better than pear orchards, and that the switch onto novel hosts might be accompanied by restricted population growth.

Journal of Chemical Ecology, 39 (3), ISSN:0098-0331, ISSN:1573-1561

Behavior genetics, 42 (4), ISSN:0001-8244, ISSN:1573-3297

The golden-haired bark beetle, Hylurgus ligniperda, is one of the most common insects normally associated with New Zealand export logs. Here we tested the dose-mortality responses of H. ligniperda adults, from two different origins (field vs laboratory), to methyl bromide (MB) — the most widely used fumigant worldwide and ethanedinitrile (EDN), a new fumigant currently being considered as very promising for MB replacement. Naked insects were fumigated with either MB or EDN at 10˚C for 4 and 3 hours, respectively. Adults from the laboratory had been reared on an arti cial diet and under controlled conditions for over 10 generations at the time of the experiments. Field adults, on the other hand, had been recently collected from Lindgren funnel traps with lures of alpha-pinene and ethanol. Our results showed that there is a significant difference in the tolerance to the two fumigants tested according to the origin of the insects, with field-collected adults being less tolerant to MB and EDN than laboratory-reared ones. The implications of our results for the development of disinfestation schedules for New Zealand export logs will be discussed.

Ethanedinitrile (EDN) is a potential alternative fumigant to methyl bromide for the phytosanitary treatment of timber and logs. Previously, adult golden-haired bark beetles (Hylurgus ligniperda) have shown high rates of tolerance to EDN, while all life stages of burnt-pine longhorn beetles (Arhopalus ferus) were highly susceptible. These results suggest that the fumigant mode of action might be species-specific and more complex than previously thought. Therefore, the anatomy of these beetles was examined to investigate potential differences in EDN toxicity related to these insect traits. The mesothoracic and fourth abdominal cuticles of 20 individuals were measured and compared across the two species. Spiracle sizes of 20 adult insects were also measured and compared across and within species. Of the two species, A. ferus had the thicker dorsal thoracic and abdominal cuticle. Adults of A. ferus had also the larger total spiracle area. These results provide important information to help explain the observed differences in EDN tolerance across the two species. Further work will test the main route of entry of EDN into the bodies of target insects and additional effects on EDN on insect behaviour.

The cotton aphid (Aphis gossypii Glover) is a cosmopolitan pest species consisting of various host plant-associated lineages that appear to have different patterns of insecticide resistance, electrophoretic banding, and reproductive output across alternative host species. Debate continues as to whether these differences represent intraspecific variation or indicate a complex of cryptic or sibling species. We studied the host plant-related ecology of two asexual lineages of A. gossypii associated with the families Malvaceae and Cucurbitaceae, respectively, in particular the host plant finding and acceptance processes of the alate forms. The two lineages proved to be differentiated across host plants in terms of: (1) their landing and settling behaviour, nymphal production rate, and subsequent colony establishment (i.e. nymphal survival and development) and (2) their sensory abilities in relation to host plant-derived odours. Furthermore, genetic structuring according to host plant type was detected using the gene for elongation factor 1-α. The magnitude of the genetic differentiation across lineages was low, perhaps indicating a relatively recent divergence. The results demonstrate: (1) the presence of (at least) two cryptic species within the current definition of A. gossypii, as anticipated in previous studies, and (2) the practicalities of using a multidisciplinary approach to understanding the 'limits' of asexual species. If sexuals can be generated from each of these lineages, this conclusion will be open to further testing.

We tested the most widely held theory about the mode of action of petroleum spray oils (PSOs) on insects (i.e. anoxia). An nC24 petroleum oil was applied topically to cotton aphids (Aphis gossypii) and cluster caterpillars (Spodoptera litura), which then showed signs of mortality that are inconsistent with anoxia. The insects died soon after treatment, with most of the mortality occurring within the first 10min. Toxicity symptoms included loss of locomotory ability, unusual abdominal contractions associated with spiracular fluttering, and ultimately dehydration and necrosis within 24h. We therefore investigated the main mechanism(s) by which the nC24 petroleum oil interacts with the insects' cells and organs, and ultimately kills the insects. The results suggest a mode of action that relates to the liphophylic properties of the oil. This includes rapid penetration through the insect cuticle followed by accumulation in the lipid-containing tissues, mainly those of the CNS, and finally penetration into the nerve cells themselves. In vitro tests with isolated insect cells further revealed that the oil penetrates the cytoplasm and induces 100% mortality of these cells within 2min of application. No signs of oil accumulation within the tracheae were observed, so it is unlikely that anoxia is taking place at any stage of the intoxication process. Electrophysiological studies confirm that oil accumulation in the nerve ganglia has the direct effect of suppressing synaptic transmission in insect ganglia as well as in the neuromuscular junctions of vertebrates (toads and rats). These results demonstrate conclusively that at least some modern PSOs do not kill insects by anoxia, but by a range of cellular disruptions that lead to rapid insect death. The implications of our findings for the development of oil-based integrated pest management strategies are discussed.

1. The common blossom thrips, Frankliniella schultzei, is a polyphagous anthophilic species that colonises a wide range of host-plant species across different plant taxa. The environmental cues used by these polyphagous insects to recognise and locate host plants are not known. We therefore determined if colour is an important environmental signal used by F. schultzei to recognise flowers of eight of its more significant host-plant species. 2. The effect of flower colour on the colonisation of different host plant species by F. schultzei was investigated by collecting and analysing the following: (a) numbers of thrips from different heights and aspects of the primary host plant Malvaviscus arboreus, (b) thrips distribution within flowers of Hibiscus rosasinensis, (c) colour reflectance from flowers of eight different host-plant species, and (d) reflectance from different coloured sticky traps and the number of thrips trapped on them at different times of the day and on different dates. 3. The results indicate that: (a) the thrips (both sexes) concentrate towards the top of the primary host plant M. arboreus and are not distributed differentially according to sunny or shady aspect of the plant, (b) the number of female thrips on H. rosasinensis was higher in anthers compared to petals (corolla) and the basal parts of the flower, and males were as numerous on the petals as were females, and (c) there is a common floral reflectance pattern (but with different intensities) across the eight host plant species, mainly in the red part of the spectrum (600-700 nm). 4. Results of colour sticky trapping show that red attracts more female thrips compared to any other colour and that most were caught between 09.00 and 11.00 hours. By contrast, more male thrips were trapped between 07.00 and 09.00 hours. Males were more evenly distributed across the different colours but the highest numbers were associated with the yellow traps. 5. The higher densities of thrips at the top of their host plant may be related to the early morning (07.00-11.00 hours) activity of the thrips, when the top portions of the plant are more exposed to sunlight. The sex-related distributions of F. schultzei thrips across time, coloured sticky traps, and various parts of the flowers seem to be related to mating swarm formation by the males, on the one hand, and the relative frequency and intensity of the use of M. arboreus by the females, on the other, as a feeding and oviposition site. Frankliniella schultzei females respond more strongly to red than to any other colours, so it is predicted that the spectral properties of colour recognition by this species will correlate with the predominant red reflectance of its primary host, M. arboreus, and that there may well be a sex-related difference in colour recognition within this species.

The primary mode of action of petroleum spray oils (PSOs) on pest insects is through direct contact. Indirect effects are, however, also possible, and deposits of the oils may influence pest populations by killing insects and/or by influencing their behaviour. The indirect effects of deposits of a new nC24 oil against the cotton aphid, Aphis gossypii Glover, were therefore determined. The effects of oil deposits on the acceptance of cotton as host plant by the aphids were assessed, as well as aphid mortality rates and their success in the establishment of colonies. The efficacy of deposits of a heavier oil (nC27) was also evaluated. Deposits of PSO were toxic to A. gossypii and remained effective until 8 days after spraying. Mortality decreased with time, so that, the older the deposit, the lower was the mortality. Significantly higher aphid mortalities were achieved on younger leaves than on mature ones. Thus, leaf age proved a significant factor in the efficacy of the deposits. Consecutive prophylactic applications (at 9 day intervals) did not have a cumulative effect, and their killing power proved to be independent of one another. Thus, applying the oil prior to aphid infestations would confer only minimal protection. The mortality inflicted by the deposits was not improved by increasing the molecular mass of the oil used (nC27 oil), but the toxic life of the oil deposit was increased. Oil deposits did not deter alates from landing on oil-sprayed plants. Oil deposits did, however, affect subsequent alate and nymphal survival, and thus the establishment of aphid colonies. The impact that the oils could have on the longer-term development of aphid populations in the field was thus demonstrated. First- and second-instar nymphs were the most susceptible life stages, with > 50% mortality compared with < 10% for the other stages. These nymphs did not show the typical signs of oil-induced mortality observed in aphids killed by direct oil applications, which suggests an alternative mode of action to that of the directly applied oil. Anoxia does not seem to be involved in either process, and alternative modes of action of the oil deposits are discussed. The implications of these findings for cotton aphid control are also considered, primarily in relation to the timing and frequency of oil application. (c) 2007 Society of Chemical Industry.

Petroleum spray oils (PSOs) kill insect pests on contact, and the composition of modern PSOs is substantially different from the ones introduced earlier. The effects of direct application of a new nC24 PSO on the cotton aphid, Aphis gossypii Glover, were therefore determined. This covered not only aphid mortality rates but also the way in which the oils affected aphid behaviour at the time of contact with the oil. Direct application of the nC24 oil proved to be highly effective in controlling A. gossypii at a range of concentrations between 1 and 10% v/v. The oil killed cotton aphids quickly, with most of the mortality occurring within the first 10 min of spraying. The fast killing action of the oils prevented any behavioural responses by the aphids. Aphids killed by the oils became flaccid and their legs and antennae extended horizontally relative to the body axis. With time, their cuticle became very shiny and began to darken. The quick death of the aphids suggested a contact mode of action of the oils, an interpretation supported by the lack of any negative effect on aphids not initially reached by the oils. However, those aphids not hit by the oils, but that subsequently encountered oil-treated areas when they moved elsewhere, also died, indicating that the oil deposits are also toxic to the aphids. The mode of action of the oil thus seems to be versatile, and the means by which it kills the aphids may be more complex than anoxia, which is the widely claimed mechanism attributed to PSOs. This oil now needs to be tested for any possible indirect effects on the cotton aphid (e.g. through its host-plant acceptance behaviour). The implications of the present findings for cotton aphid control and assessment of PSO efficacy in the field are discussed.

Compensation growth and chemical defense are two components of plant defense strategy against herbivores. In this study, compensation growth and the response of primary and secondary metabolites were investigated in Brassica rapa plants subjected to infestation by two herbivores from contrasting feeding guilds, the phloem-feeding aphid Brevicoryne brassicae and the leaf-feeding caterpillar Pieris brassicae. These specialist herbivores were used at two different densities and allowed to feed for seven days on a young caged leaf. Changes in growth rates were assessed for total leaf area and bulb mass, whereas changes in primary and secondary metabolites were evaluated in young and mature leaves, roots, and bulbs. Mild stress by caterpillars on young plants enhanced mean bulb mass and elicited a contrasting regulation of aliphatic and indolic glucosinolates in the leaves. In contrast, mild stress by aphids enhanced leaf growth and increased glucosinolate concentrations in the bulb, the most important storage organ of B. rapa. A similar mild stress by either herbivore to older plants did not alter plant growth parameters or concentrations of the metabolites analyzed. In conclusion, Brassica plant growth was either maintained or enhanced under mild herbivore stress, and defense patterns differed strongly in response to herbivore type and plant development stage. These results have implications for the understanding of plasticity in plant defenses against herbivores and for the management of Brassica rapa in agroecosystems., Journal of Chemical Ecology, 40 (2), ISSN:0098-0331, ISSN:1573-1561

Development of sciencebased fumigation schedules for phytosanitary treatments relies on an understanding of the factors which influence the effectiveness of a fumigant under different conditions Understanding the sorption characteristics of a fumigant is a critical step in establishing commercial treatment schedules as this process which involves adsorption and absorption of fumigant molecules influences the concentration of the fumigant remaining in the treated space after fumigation and hence the amount of fumigant available to kill insects We monitored the concentration of methyl bromide during commercial fumigation of three log stacks (average volume 4078 m3) with 120 g/m3 methyl bromide for 13 h under a tarpaulin Pine (Pinus radiata D Don) logs were fumigated at South Port Bluff (New Zealand) during April 2015 Gas samples from the treated space were taken at 05 1 2 3 the treated space indicating that the rest of the fumigant was sorbed These data can now be combined with insect toxicity studies to guide the development of improved commercial treatment schedules to treat log exports from New Zealand

Plants growing under elevated CO₂ concentration may acclimatize to this environmental change by modification of chemical, physiological, and/or morphological traits. As a consequence, not only plant functioning but also plant-insect interactions might be altered, with important consequences particularly for agricultural systems. Whereas most studies have focused on the plant acclimation effects of elevated CO₂ with regard to crop growth and productivity, acclimation effects on the behavioral response of insects associated with these plants have been largely neglected. In this study, we used a model system comprised of Brussels sprout Brassica oleraceae var. gemmifera and a specialized herbivorous insect, the cabbage aphid Brevicoryne brassicae, to test for the effects of various periods of exposure to an elevated (2× ambient) CO₂ concentration on key plant functional traits and on host plant location behavior by the insect, assessed as plant colonization rates. Elevated CO₂ had no measurable effect on colonization rates or total plant volatile emissions after a 2-week exposure, but it led to 15 and 26 % reductions in plant colonization rates after 6- and 10-week exposures, respectively. This reduction in plant colonization was associated with significant decreases in leaf stomatal conductance and plant volatile emission. Terpene emission, in particular, exhibited a great reduction after the 10-week exposure to elevated CO₂. Our results provide empirical evidence that plants might acclimatize to a future increase in CO₂, and that these acclimation responses might affect host plant choice and colonization behavior by herbivorous insects, which might be advantageous from the plant's perspective.

SUMMARY Ratios of compounds in host plant odors fluctuate with the phenological stage of the plant. In the present study, we investigated the effect of changing ratios of host plant volatile constituents on herbivore insect attraction and olfactory information processing. We tested a synthetic mixture of bioactive peach shoot volatiles with different concentrations of one of the mixture constituents, benzonitrile, on oriental fruit moth Cydia (=Grapholita) molesta females. Y-tube olfactometer bioassays showed that female attraction to the mixture was maintained while increasing the benzonitrile level up to 100 times. Further increases led to behaviorally ineffective mixtures. Then, we recorded odor-evoked neural activity patterns in the antennal lobes, the main olfactory center of the brain, using calcium imaging. Benzonitrile-containing mixtures elicited strong activation in two glomeruli, which were found to process mixture-related information in specific ways. Activation in one glomerulus directly paralleled behavioral effects of the different ratios tested whereas a deviating pattern was noted in the other glomerulus. Our results indicate that the ratio of constituents in a volatile mixture can be varied to a certain degree without reducing female attraction. Thus, volatile blends in nature might vary quantitatively within a certain range without affecting odor-guided host location. Neurophysiological results showed that the processing of mixture-related information inside the antennal lobes is not uniform across glomeruli. Thus, final processing of this information probably takes place in higher-order brain centers.

The cotton aphid, Aphis gossypii, has a worldwide distribution and causes damage to numerous economically important crops. The bacterial symbionts associated with cotton aphids, sampled mainly from malvaceous and cucurbitaceous plants within Japan and Australia, were characterised using molecular profiling approaches. The goal was to document the aphid symbionts present and determine if patterns of microbial diversity are consistent with the existence of host plant related cryptic species in A. gossypii. The bacterial profiles of the aphids are diverse and reflect local geography more than host plant use.