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Walnut dusky-veined aphid Panaphis juglandis (Goeze) and walnut green aphid Chromaphis juglandicola (Kaltenbach) cause economic losses and co-occur on walnut trees, but they have separate niche. Panaphis juglandis feeds on the upper (adaxial) surface of leaves while C. juglandicola feeds on the lower (abaxial) surface. Field surveys and controlled experiments in the field and laboratory were conducted to determine microhabitat selection by P. juglandis and C. juglandicola and the factors associated with this behavior. In the field, the two aphid species colonized a leaflet as follows: P. juglandis only, 16.5%; C. juglandicola only, 44.5%; and both species on same leaflet, 39%. C. juglandicola settled on the abaxial surface earlier than P. juglandis settled on the adaxial surface. P. juglandis showed the highest reproduction rate when they were in the erect position on the adaxial surface. C. juglandicola exhibited the highest reproduction rate when they were inverted and on the abaxial surface. Under a light intensity of 50,000 lux, 60.5% of C. juglandicola remained on the illuminated surface, while P. juglandis did not move from the illuminated surface. Through field and laboratory experiments, we found that P. juglandis preferred to settle on the adaxial surface and C. juglandicola preferred to settle on the abaxial surface. Leaf surface, gravity, and light were three physical factors affecting microhabitat selection by the two aphid species but light intensity was the key factor. This information will help to better understand the habitats of two aphid species, which may be helpful for walnut aphids management strategies such as the usage of insecticides option and spraying.

The apple buprestid, Agrilus mali Matsumura, that was widespread in north-eastern China, was accidently introduced to the wild apple forest ecosystem in mountainous areas of Xinjiang, China. This invasive beetle feeds on domesticated apples and many species of Malus and presents a serious threat to ancestral apple germplasm sources and apple production worldwide. Estimating the potential area at risk of colonization by A. mali is crucial for instigating appropriate preventative management strategies, especially under global warming. We developed a CLIMEX model of A. mali to project this pest's potential distribution under current and future climatic scenarios in 2100 using CSIRO-Mk 3.0 GCM running the SRES A1B emissions scenario. Under current climate, A. mali could potentially invade neighbouring central Asia and eventually the mid-latitude temperate zone, and some subtropical areas and Pampas Steppe in the Southern Hemisphere. This potential distribution encompasses wild apples species, the ancestral germplasm for domesticated apples. With global warming, the potential distribution shifts to higher latitudes, with the potential range expanding slightly, though the overall suitability could decline in both hemispheres. In 2100, the length of the growing season of this pest in the mid-latitude temperature zone could increase by 1–2 weeks, with higher growth rates in most sites compared with current climate in mid-latitudes, at least in China. Our work highlights the need for strategies to prevent the spread of this pest, managing the threats to wild apples in Tian Shan Mountain forests in Central Asia, and commercial apple production globally. We discuss practical management tactics to reduce the spread of this pest and mitigate its impacts.

In 1993, the apple buprestid, Agrilus mali Matsumura (Coleoptera: Buprestidae) native to northeast Asia, invaded the Yili River valley, Xinjiang Uyghur Autonomous Region, China. It is now widespread across 95% of wild apple forests (Malus sieversii (Ledeb.) Roem) in the region. This invasive species poses a major threat to wild apple populations serving as the key germplasm refuge for the ancestor of domestic apples across 6 countries in Central Eurasia. We first described the symptoms and damage caused by A. mali to wild apple trees, and then assessed the abundance of A. mali and tree damage under four different management strategies in three consecutive years (2016–2018): release of commercial biocontrol agents, aerial spraying of insecticide, aerial spraying/pruning, and establishment of fenced areas aiming to preserve understory veg-etation and enhance natural pest control. The apple buprestid feeds on inner bark and preferentially damages the small branches (1–4 cm in diameter) located in the canopy 4–6 m above ground. The average fruit production declined from 90 kg to 10 kg per tree after the pest invasion. Pest abundance, as measured by counting damage scars, declined in sprayed areas. Fenced areas had higher pest abundance (damage). Fruit production in biological control and spraying/pruning areas increased slightly, while tree damage ranking declined over the years. Our results suggest that a combination of biological control and spraying/pruning may contribute to pest management of A. mali and resilience of wild apple forests in Central Eurasia.

Cuticle sclerotization is critical for insect survival.

The article provides new information on the phenology of a serious insect pest, the species of Archips rosana (Linnaeus, 1758) (Lepidoptera: Tortricidae), rendering fundamental harm to the Sievers apple trees, native to the Trans-Ili Alatau region (the North Tian Shan), which was not previously covered by studies. Material for research was obtained by the authors during two field seasons 2018-2019 by catching with an entomological net and making observations in nature at monitoring sites, as well as by growing all stages of development of the leafrollers in laboratory conditions of the Institute Zoology of Republic of Kazakhstan. The main objectives of the paper were set as follows: To establish the environmental factors behind the development stages of the A. rosana pest, to determine its phenological features and to identify the most vulnerable stage in its development in the given area. The paper describes in detail the study method and its outcome, workable in dealings against propagation of the pest and saving the indigenous Sievers apple tree. As a result, the most vulnerable stage convenient for combating the pest is the stage of the 1st - 3rd instar larvae which appear in the Trans-Ili Alatau during the period from the second decade of April to the second decade of May.

Wild apple Malus sieversii (Ledeb.) M. Roem. (Rosales: Rosaceae), the ancestor of cultivated apples, is widely distributed in Central Asia and is recognized as an important germplasm bank. Recently, the invasive pest Agrilus mali Matsumura (Coleoptera: Buprestidae), originally distributed in eastern Asia, has damaged endemic apple forests in the Yili River valley, Xinjiang, China, and has spread rapidly, infesting more than 80% of wild apple trees in this region. We investigated the life-history traits and native natural enemies in the recently invaded range during 2016 and 2017. Agrilus mali has a univoltine life cycle and overwinters as young larvae in galleries in the cambium. Adults emerged from early June to mid-August and their density peaked in mid-July. Several native natural enemies were identified from Agrilus mali larvae, including Atanycolus denigrator (L.) (Hymenoptera: Braconidae), the mite Pyemotes moseri Yu et Liang (Acari: Pyemotidae) and fungal entomopathogens. Combined, these natural enemies were responsible for mortality rates ranging from 20% to 80% during the summer and autumn. The most abundant and important natural enemy was A. denigrator, which was responsible for up to 15% mortality of A. mali. The results of the present study suggest that augmentation and conservation of A. denigrator and P. moseri should be considered with respect to biological control against this devastating pest.

Host plants indirectly affect parasitoid life-history traits via parasitoid hosts. Here, we evaluated the life-history traits of the parasitoid Aphelinus varipes emerging from the green peach aphid, Myzus persicae (Hemiptera: Aphididae), feeding on five commercially important vegetables. The results showed that A. varipes fed upon and parasitized maximum number of aphids grown on chili pepper, and least on cabbage. The emergence rate was the highest on chili pepper (100%) and lowest on crown daisy (71.1 ± 2.17%). Aphelinus varipes developed fastest on hosts reared on chili pepper (12.9 ± 0.02 d) and slowest on aphids reared on cabbage (14.1 ± 0.02 d). The body weight and body size of emerging wasp parasitoids and aphids were greatest on chili pepper and lowest on cabbage. Aphid body size positively affect parasitism, development time, and body size of the parasitoid. In conclusion, our results showed that the parasitoid A. varipes had variable life-history parameters, depending on the host plant species and host body size. The effects of host plant species on performance of M. persicae and its parasitoid A. varipes are discussed, along with the potential of using A. varipes to control M. persicae on different plants.

Walnut aphids are major pests of walnut production with few commercially available natural enemies. We conducted laboratory and field experiments to evaluate the potential of Orius sauteri Poppius (Anthocoridae), a predatory bug, as a biological control agent against two walnut aphid species: the dusky-veined aphid (Panaphis juglandis Goeze) and the walnut aphid (Chromaphis juglandicola Kaltenbach). Both species co-occur on walnut trees, P. juglandis is distributed on the upper surface (adaxial) of leaves while C. juglandicola is found on the lower surface (abaxial) of leaves. Based on functional response experiments, O sauteri had a strong capacity for consuming both aphid species. Biocontrol efficacy of O. sauteri for each species in the laboratory and field experiments was high, 77% for P. juglandis and 80% for C. juglandicola, regardless if one or two predators being present. However, biocontrol efficacy declined 15&ndash, 25% for C. juglandicola and 20&ndash, 50% for P. juglandis when both aphid species were present on the same leaf. The efficacy of O. sauteri under (semi)-field conditions gave similar findings based on the percentage reduction of aphids and change in population growth rates of aphids. The reduced biocontrol efficacy of the predatory bug against mixed species populations of aphids can be explained by competition between the aphid species and differences in their preferred location on leaves. Our experiments showed that O. sauteri is a promising biocontrol agent, but biocontrol efficacy may decline when both aphid species are present on walnut trees. This should be considered in the commercial release of O. sauteri in walnut orchards to promote economic and environmental benefits of walnuts production.

Simple Summary Walnut aphids are major pests of walnut orchards with few commercially available natural enemies except parasitoids. The predatory bug (Orius sauteri) was assessed as a potential biological control agent against two walnut aphid species. This bug has a strong capacity for consuming both aphid species. Biocontrol efficacy of O. sauteri for each species was high (more than 70%), but declined about 20% when both aphid species present on the same leaf together. This might be due to the competition among two species of aphids tested. Three statistical approaches were employed to show that O. sauteri is a promising biocontrol agent. The commercial release of O. sauteri should be considered for the coexisting aphids in walnut orchards to promote economic and environmental benefits. Abstract Walnut aphids are major pests of walnut production with few commercially available natural enemies. We conducted laboratory and field experiments to evaluate the potential of Orius sauteri Poppius (Anthocoridae), a predatory bug, as a biological control agent against two walnut aphid species: the dusky-veined aphid (Panaphis juglandis Goeze) and the walnut aphid (Chromaphis juglandicola Kaltenbach). Both species co-occur on walnut trees; P. juglandis is distributed on the upper surface (adaxial) of leaves while C. juglandicola is found on the lower surface (abaxial) of leaves. Based on functional response experiments, O sauteri had a strong capacity for consuming both aphid species. Biocontrol efficacy of O. sauteri for each species in the laboratory and field experiments was high, 77% for P. juglandis and 80% for C. juglandicola, regardless if one or two predators being present. However, biocontrol efficacy declined 15–25% for C. juglandicola and 20–50% for P. juglandis when both aphid species were present on the same leaf. The efficacy of O. sauteri under (semi)-field conditions gave similar findings based on the percentage reduction of aphids and change in population growth rates of aphids. The reduced biocontrol efficacy of the predatory bug against mixed species populations of aphids can be explained by competition between the aphid species and differences in their preferred location on leaves. Our experiments showed that O. sauteri is a promising biocontrol agent, but biocontrol efficacy may decline when both aphid species are present on walnut trees. This should be considered in the commercial release of O. sauteri in walnut orchards to promote economic and environmental benefits of walnuts production.

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a destructive pest on tomato, has invaded most Afro-Eurasian countries. Recently invaded by the pest, most tomato crops in greenhouses and open fields in Tajikistan are currently suffering major damage. While failure in management using chemical insecticide has been frequently observed, alternative options such as biological control is urgently needed. In this study, we evaluated the effectiveness of the common green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) against T. absoluta. In controlled laboratory conditions, C. carnea showed high predation rate on both T. absoluta eggs (i.e., 36 &plusmn, 2 eggs within 24 h and 72 &plusmn, 4 eggs within 48 h) and larvae, especially it can attack the larvae both inside and outside the leaf galleries (i.e., an average of 22% of the larvae was killed inside, and an average of 35% was killed outside). In a cage exclusion experiment, T. absoluta showed relatively low larval density in the cages with pre-fruiting release of C. carnea, whereas the larval density was four to six times higher in the &ldquo, no release&rdquo, cages. In the &ldquo, post-fruiting release&rdquo, cages, the pest population that had already built up during the pre-fruiting stage eventually crashed. In an open-field experiment, the tomato crops in control plots were fully destroyed, whereas low levels of larvae density and damage were observed in the biocontrol plots. Moreover, the field release of C. carnea resulted in significantly higher tomato yield than those without release, despite no differences between the &ldquo, pre-fruiting release&rdquo, and &ldquo, treatments. We conclude that the local commercial biocontrol agent C. carnea could be promising for the management of T. absoluta in Tajikistan. It is also one of the first reports showing the management of T. absoluta using a lacewing species. The effectiveness should be validated by further field trials in larger area of commercial crops and various locations.

Malus sieversii(Ledeb.) M. Roem is a tertiary relict tree species and a rare and valuable resource for germplasm conservation. Since 1995, its wild forest has been severely destroyed by a devastating wood-boring beetle Agrilus mali Matsumura (Coleoptera: Buprestidae) in Xinjiang Uygur Autonomous Region, China. Where it invaded, this beetle infested more than 95% of the forests, and 80% of wild apple trees were reported dead in the hotspots. The physiological damage by A. mali infestation and their causality to tree death remain unclear. In this study, we attempted to explain the wild apple dieback from plant physiological perspectives, based on the hypothesis that the more damage M. sieversii suffered from the infestation of A. mali, the less water and fewer nutrients it could utilize. The study was conducted on trees with different extents of damage in wild apple forests over a large scale during 2016 and 2017. The stable carbon isotope ratio in leaves was analyzed to indicate tree water stress status. Total N, total P, total K, Ca2+ and Mg2+ were analyzed to reflect plant mineral nutrient status. The extent of damage was significantly associated with the leaf stable carbon isotope ratio in the drier year of 2016, but not significantly in 2017 with heavy rainfall in spring. The mineral nutrient contents of leaves were not significantly different among the four damage rankings in either year. The water stress experienced by M. sieversii was aggravated by the damage caused by A. mali, especially in a drought year, and indicates that the long-term water deficit caused by A. mali infestation may be the key factor leading to the decline of wild apple forests. The finding suggests the necessity of aerial irrigation for sustainable integrated pest management in wild apple trees.

Extensive unofficial planting of Bt cotton expressing Cry1Ac toxin has occured for the past two decades in northwestern China, and no mandatory refuge policy has been adopted. The status of Cry1Ac susceptibility of Helicoverpa armigera in this region has not been routinely monitored, nor has the susceptibility to Cry2Ab cotton which has not been released in China. The susceptibility of H. armigera populations to both toxins was assessed in 2014 and 2015 in two contrasting cotton farming systems across the region. Over the 2 years, the response to Cry1Ac of the nine H. armigera field populations sampled ranged from 3.16 to 16.94 μg ml−1 for LC50 and 0.013 to 0.741 μg ml−1 for IC50, and the baseline susceptibility of these strains to Cry2Ab ranged from 3.43 to 19.05 μg ml−1 for LC50 and 0.16 to 3.81 μg ml−1 for IC50. There was no significant difference in susceptibility to either Cry1Ac or Cry2Ab between small-holder and broad-acre farming. The susceptibility to Cry1Ac toxin in northwestern China is higher than that in northern China, while there was no difference for Cry2Ab between northwestern China and northern China. With high levels of adoption of Bt cotton and relatively limited natural refuge for H. armigera, it is important to consider resistance management measures for Bt cotton in northwestern China.

Global climate change has profound consequences on survival and reproduction of arthropods. In particular, in temperate regions changes in spring temperatures have a major impact on crop pest population dynamics, but the mechanisms remain elusive. By analysing empirical data of Helicoverpa armigera moth populations from three sites over 12–13 years in northwestern China, and running modelling (DYMEX software), we intended to clarify how the late spring cold (LSC) events affect the populations of this destructive pest species. We then explored the relationships between LSC parameters and moth population dynamics using model simulations. Our results highlight the importance of LSC in driving H. armigera population dynamics. Of the LSC parameters tested, the duration of LSC measured as the maximum continuous days with a minimum temperature lower than 10 °C (MCDL) was a key factor influencing the population abundance of the spring and summer generations. Furthermore, the model showed that the timing of the LSC event had a major effect on how the MCDL influenced each generation. The timing with respect to the eclosion of the overwintering generation was critical, and it determined the variation in the abundance of the first and subsequent generations. Our findings imply that the abundance of H. armigera will increase as the frequency and duration of LSC events decrease under global spring warming. Incorporating the duration and timing of LSC events into decision-making should improve forecasting H. armigera abundance and other insect species under global climate change and better inform pest management.

Models of global climate change predict a greater frequency and magnitude of extreme temperature events and this will have biological consequences. Aphids are vulnerable to climate warming because ambient temperature strongly affects their life history traits. We used the large cotton aphid (Acyrthosiphon gossypii M.) as a model insect to provide insights into the responses of mid-latitude (temperate zone) aphids exposed to high temperature events. The developmental time, survival and fecundity of individual A. gossypii were measured under five temperature regimes. Even though the mean daily temperature was the same (24 degrees C) for all temperature regimes, the impact of temperature fluctuations to extreme levels (36 degrees C) on aphid fitness was clearly different to the impact of constant temperature. Negative effects on the aphid's life history traits occurred under all four fluctuating temperature regimes. Our study shows that cooler intervals may help the insect to tolerate potentially lethal high temperatures under naturally occurring conditions. The results will help us to understand the changes to aphid population dynamics likely to be associated with global warming in the future, and to design management practices for this pest species in cotton-growing areas in mid-latitudes such as central Asia.

Since its initial detection in Turkey in 2009, the invasive destructive pest South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has started its new invasion journey to east and invaded most Asian countries. This pest currently causes extensive damage to tomato production and potentially threatens key production areas such as China. To provide an overview of current status of T. absoluta in Asia, we have briefly reviewed the damage and economic impacts by this pest locally and discussed why this species has spread so rapidly among the countries. Moreover, ongoing integrated pest management options are summarized in newly invaded areas with an emphasis of discussing the potential control failures by chemical insecticides. Future research efforts on developing promising management technologies are recommended. Finally, we suggest building a cross-regional network to enhance the sustainable control of this pest.

Native to Asia, the spotted lanternfly, Lycorma delicatula (White), is an emerging pest of many commercially important plants in Korea, Japan, and the United States. Determining its potential distribution is important for proactive measures to protect commercially important commodities. The objective of this study was to assess the establishment risk of L. delicatula globally and in the United States using the ecological niche model MAXENT, with a focus on Washington State (WA), where large fruit industries exist. The MAXENT model predicted highly suitable areas for L. delicatula in Asia, Oceania, South America, North America, Africa, and Europe, but also predicted that tropical habitats are not suitable for its establishment, contrary to published information. Within the United States, the MAXENT model predicted that L. delicatula can establish in most of New England and the mid-Atlantic states, the central United States and the Pacific Coast states, including WA. If introduced, L. delicatula is likely to establish in fruit-growing regions of the Pacific Northwest. The most important environmental variables for predicting the potential distribution of L. delicatula were mean temperature of driest quarter, elevation, degree-days with a lower developmental threshold value of 11°C, isothermality, and precipitation of coldest quarter. Results of this study can be used by regulatory agencies to guide L. delicatula surveys and prioritize management interventions for this pest.

The coexistence of species competing for resources can be facilitated by differential effects of temperature on fitness components. The coexisting cotton aphids Aphis gossypii Glover and Acyrthosiphon gossypii Mordvilko show seasonal differences in abundance in North-Western China, the former reaching higher field abundances and declining later in the season than the latter. We hypothesized that differences in responses to temperature might be the proximate mechanism driving this difference in population dynamics between the two species. Aphids from laboratory-reared colonies and directly collected from the field in early summer were used to study their development, survival and reproduction under a range of constant temperatures. Life-table parameters suggest that A. gossypii performed better than Ac. gossypii under all temperature treatments tested, and the difference tended to be strongest under high temperatures. These observations are consistent with the higher numbers and the later decline o...

International audience; The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an invasive destructive pest of tomato and other solanaceous plants. Since its first detection in Spain in 2006, the pest has started its invasion across the Afro-Eurasian super-continent. Xinjiang Uyghur Autonomous Region of China, adjacent to the recently infested central-Asia countries, being the largest tomato growing region worldwide, is now under high invasion risk. Considering the importance of this issue, we must plan ahead to be fully prepared for the potential invasion of this pest in near future. In this paper, we call for upcoming studies to address several aspects including the overwintering biology, diapause, dispersion, population ecology in outdoor crops and insecticide resistance of invading populations. Moreover, the effective management options are proposed based on the control experience in its native range and recently infested countries. Our "look-ahead" proposal not only serves as a guideline for elaborating the pest management strategy in Xinjiang in near future, but can also interest the rest of the tomato-producing regions worldwide that have not been infested yet by the moth.

The relationship between pest population dynamics and habitat management in landscape scale is full of challenge and interest. To understand the effects of oasis agro-landscape complexity on the population dynamics of cutworms, intelligent telemetry light traps were installed in three different agricultural landscapes in the Tarim Basin, North-Western China-complex landscape A (mixture with cotton and greenhouses), complex landscape B (mixture with cotton and grains), and a simple landscape (mostly cotton). GPS was used to investigate the agricultural landscape structures in a 2 km radius around the light traps with the support of Google Earth maps. The landscape diversity indexes of the two kinds of complex agricultural landscapes (complex landscapes A and B) were significantly higher than that in the simple landscape. Different species of cutworms showed different responses in the cropping landscapes. There were no significant differences in the population numbers of Agrotis segetum among the three different landscapes. In contrast, the population sizes of Amathes c-nigrum and Agrotis exclamationis in complex landscape B were larger than that in complex landscape A and the simple landscape. The population growth rate of cutworms was higher in complicated landscape B than in the other landscapes. The population dynamics of pests in complex agricultural landscapes did not show large fluctuations, compared with those in the simple landscape due to crop harvest. The results of this study can be implemented to maximize the biological pest control in cropping landscape.

Transgenic Bt-cotton now dominates the cotton-growing belt in northwestern China where there are few natural plant refuges to act as sources of moths susceptible to Bt toxin. As an initial step towards developing an insect resistance management (IRM) plan for the pest moth, Helicoverpa armigera, on Bt-cotton in this part of China, we assessed the potential of six crops grown in two configurations to act as refuge hosts for susceptible moth production in both broad-acre and small-holder farms. Egg and larval abundance indicated that H. armigera had a preference for chickpea, pigeon pea, and corn, over cotton, sorghum, and benne (sesame). There were no significant differences in egg or larval abundance between plot and strip configurations of these crop hosts. We found that sorghum was not attractive to H. armigera, contrary to the findings in other cotton production areas. Moreover, chickpea, pigeon pea, and corn were determined to be potential refuge hosts based on egg and larval abundance over the growing season. From the adult moth population dynamics in broad-acre and small-holder farms, the efficiency of alternative refuge crops, and local agricultural practices, we recommend that spring corn be grown as a strip crop as part of an IRM strategy to improve the probability of Bt-susceptible moth production and mating with resistant moths in broad-acre farms. In small-holder farms where current agricultural practices are entrenched, wheat and summer corn should be evaluated as refuge crops in the future.

Acyrthosiphon gossypii is a widespread, major pest of cotton in central Asia. Effects of specific temperatures on A. gossypii development and survival are unknown and would be useful in helping interpret population dynamics and devising management tactics for this pest. In this paper, the effect of temperature on the life table of A. gossypii reared on cotton was evaluated under laboratory conditions using temperatures of 18, 21, 24, 27, and 30 °C. The developmental rate of immatures increased exponentially from 18 to an optimum around 27 °C and then declined. The estimated lower developmental threshold was 8.0 °C, and 107.5 degree days were required for development from the first instar to adult. The percentage survival of immature stages varied from 81 to 91 % within the range of 18-27 °C. Survival declined to 27 % at 30 °C. The average longevity of adult females was 15.7, 11.7, 8.2, 5.2, and 2.8 days, and the average number of offspring produced per female was 46, 38, 20, 14, and 0, at temperatures of 18, 21, 24, 27, and 30 °C, respectively. From 21-27 °C, the intrinsic rate of increase of A. gossypii was significantly higher than at 18 °C, indicating that 21–27 °C was within the optimal range for the growth of A. gossypii, and that 30 °C constant is beyond the upper limit for reproduction. The observations will form the basis of a forecasting system and could account for the decline of the species on cotton in central Asia as well as other regions during hot summer months.

A new genus, Arcuatitibia Luo, Lu & Cai, and one new species, A. kerzhneri Luo, Lu & Cai, are described in the subfamily Reduviinae, based on the materials from Xinjiang, China. The dorsal habitus, male genitalia, and other diagnostic morphological features are illustrated.