Evaluation of Food Security in North China Based on Food Production Level.

This paper focuses on county-level grain production and food security in North China; selects 17 indicators from both climatic conditions and human activities; applies yield fluctuation coefficients, spatial econometric modelling, the random forest method, and factor analysis to study the characteristics of grain production in North China and the influencing factors; and evaluates the situation of food security in North China based on grain production capacity. The following results were obtained: (1) The spatial and temporal changes in grain production located in North China from 2000 to 2020 are obvious. The grain output in North China from 2000 to 2020 maintains fluctuating growth at a rate of 0.38 × 1011 kg/10a. The east and south are the key areas for grain production in North China. Grain output was relatively stable except for 2003. with the cold spots of grain production being mainly in the northwestern area and the hot spots in the central and southern areas. (2) The changes in grain production in North China from 2000 to 2020 were less affected by climate and mainly influenced by human activity indicators. (3) As time progresses, the area of food shortage zones decreases in size, becoming evenly distributed and dispersed from the initial concentration in northern Hebei and most of Shanxi; the change in the supply-demand equilibrium zones is not obvious; and the area of surplus grain zones increases markedly in size, with a tendency to expand from the south and centre of the study area to the west and north. The grain production capacity of counties in the northwest and north is generally low, and even counties located in surplus grain areas have potential food security risks. However, in the east and south, due to their high grain production capacity, the per capita grain supply situation may be alleviated even in counties located in grain shortage areas. This study can deepen the understanding of the characteristics of food production in North China and enrich the research on food security. Analyses of factors influencing food production will improve a deeper understanding of food security. Food security evaluation based on food production capacity will contribute to a more precise and comprehensive understanding of the food security pattern in North China.

Defense mechanism of Fe(III)-assisted anammox under salt stress: Performance and microbial community dynamics.

Anammox process has attracted attention due to its excellent nitrogen removal properties in nitrogen-rich wastewater treatment. However, there were some obstacles for the application of anammox to treat high saline wastewater due to its sensitivity to salinity. In this study, Fe(III) addition strategy was developed to assist anammox to adapt high saline surroundings, with the defense mechanism involved in Fe(III)-assisted anammox emphasized. Nitrogen removal performance of anammox was deteriorated at 3.5% salinity, with the average total nitrogen removal rate of 0.85 kg/(m3·d) observed. The continuous addition of Fe(III) could significantly assist anammox to resist high salinity through facilitating the enrichment of anammox species. Candidatus Kuenenia was the main anammox species and outcompeted Candidatus Brocadia under high saline surrounding. The relative abundance of Candidatus Kuenenia increased with increased salinity and reached 41.04% under 3.5% salinity. The synthesis of key enzymes of anammox species were improved through Fe(III) addition and then facilitated the energy metabolism of anammox bacteria under 3.5% salinity. This study provides a new thought in Fe(III)-assisted anammox enhancement technologies and deepens the insight of anammox in high saline wastewater treatment.

Design and Preparation of Avermectin Nanopesticide for Control and Prevention of Pine Wilt Disease.

Pine wilt disease is a devastating forest disaster caused by Bursaphelenchus xylophilus, which has brought inestimable economic losses to the world's forestry due to lack of effective prevention and control measures. In this paper, a porous structure CuBTC was designed to deliver avermectin (AM) and a control vector insect Japanese pine sawyer (JPS) of B. xylophilus, which can improve the biocompatibility, anti-photolysis and delivery efficacy of AM. The results illustrated the cumulative release of pH-dependent AM@CuBTC was up to 12 days (91.9%), and also effectively avoided photodegradation (pH 9.0, 120 h, retention 69.4%). From the traceable monitoring experiment, the AM@CuBTC easily penetrated the body wall of the JPS larvae and was transmitted to tissue cells though contact and diffusion. Furthermore, AM@CuBTC can effectively enhance the cytotoxicity and utilization of AM, which provides valuable research value for the application of typical plant-derived nerve agents in the prevention and control of forestry pests. AM@CuBTC as an environmentally friendly nanopesticide can efficiently deliver AM to the larval intestines where it is absorbed by the larvae. AM@CuBTC can be transmitted to the epidemic wood and dead wood at a low concentration (10 mg/L).

Myzus persicae Management through Combined Use of Beneficial Insects and Thiacloprid in Pepper Seedlings.

Excessive insecticide application has posed a threat to pollinators and has also increased insecticide resistance of Myzus persicae Sulzer. Therefore, it is urgent to develop an economical and effective strategy, especially for greenhouse vegetables. Firstly, we selected a neonicotinoid insecticide that is specifically fatal to M. persicae but relatively safe to predators and bumblebees by laboratory toxicity tests and risk assessments. Then, we tested the effectiveness of the neonicotinoid insecticide under different temperature conditions. According to the LC50 values and the hazard quotients, thiacloprid met the requirements. Greenhouse trails indicated that thiacloprid was quite efficient, while control dropped to 80% without the application of thiacloprid. As for biological control, Harmonia axyridis effectively controlled 90% of aphids with thiacloprid or not. However, Aphidoletes aphidimyza performed better above 20 °C. Our results indicated that it is cost-effective to control M. persicae with A. aphidimyza in suitable temperature conditions and H. axyridis was more effective at low temperatures. Practically, thiacloprid could be used either as an emergency option to control aphids' abundance alone or in combination with natural enemies.

Influence of temperature on the development and reproduction of Cinara cedri (Hemiptera: Aphidoidea: Lachninae).

Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.

Unraveling the nitrogen removal properties and microbial characterization of "Candidatus Scalindua"-dominated consortia treating seawater-based wastewater.

"Candidatus Scalindua", as known as marine anammox bacteria (MAB), was engineered to remove nitrogen from seawater-based wastewater (SWW). In this study, "Candidatus Scalindua" was successfully enriched within 106 days with marine sediments as inoculated sludge. The operating temperature was 20 ± 2 °C, and influent pH was 7.5 ± 0.1. Ammonia (NH4+-N) removal rate (ARR) was 0.53 kg/(m3·d) with the NH4+-N loading rate of 0.68 kg/(m3·d), and nitrite (NO2--N) removal rate (NRR) was 0.57 kg/(m3·d) at 0.89 kg/(m3·d) NO2--N loading rate. Nitrogen removal was negatively affected at an influent NO2- above 224 mg/L, which decreased the ARR and NRR to 0.36 and 0.31 kg/(m3·d), respectively. The genus "Ca. Scalindua" dominated the reactor, and it synergistically coexisted with Marinicella to achieve efficient nitrogen removal. This work would help to better understand the nitrogen removal properties and microbial characterization of MAB in SWW wastewater treatment under low temperature.

Sensilla on antennae and mouthparts of adult spruce bark beetle Ips typographus (Coleoptera: Curculionidae).

The spruce bark beetle, Ips typographus, is an invasive forest pest that occurs across Eurasia. To further understand the mechanism of insect-host chemical communication and the feeding choices of adult I. typographus, we examined the sensilla on the antennae and mouthparts of I. typographus using scanning electron microscopy. No sexual dimorphism in sensilla type or distribution was observed. Ten subtypes of antennal sensilla were identified: sensilla trichodea Types I-III (TR1 , TR2 , and TR3 ); sensilla chaetica Types I and II (CH1 and CH2 ); sensilla basiconica Types I-III (BA1 , BA2 , and BA3 ); sensilla coeloconica (CO); and Böhm sensilla (BS). BA2 were the most abundant among the antennal sensilla in both sexes. Thirteen mouthpart sensilla subtypes were observed: sensilla trichodea Types I-IV (TR1 , TR2 , TR3 , and TR4 ); sensilla chaetica Types I-III (CH1 , CH2 , and CH3 ); sensilla digitiformia (DI); sensilla basiconica Types I-II (BA1 and BA2 ); and sensilla styloconica Types I-III (ST1 , ST2 , and ST3 ). Among these, TR4 were the most abundant in both sexes. The apex of each maxillary and labial palp carried the same sensilla (BA2 , ST1 , ST2 , and ST3 ), although the apex of the maxillary palp contained more total sensilla. The functional roles of each sensilla type are discussed based on their external structure and distribution. The results provide a theoretical basis for further studies on the olfactory and feeding behaviors and electrophysiology of adult I. typographus.

Self-assembled bovine serum albumin nanoparticles as pesticide delivery vectors for controlling trunk-boring pests.

BACKGROUND: Trunk-boring pests (TBPs) are an important type of forest pest, TBPs not only feed on the branches and trunks of trees, but also spread quarantine diseases in forests. However, because the larvae of TBPs live inside the trunk and are well concealed, prevention and control are difficult. The lack of effective control methods leads to the death of many trees in forests. In this study, a novel nanopesticide featuring high bioactivity and slow-release properties was developed to control TBPs. Thiacloprid (THI), which is commonly used to control Coleoptera species, was used as a model pesticide. RESULTS: The oleophobic properties of bovine serum albumin (BSA) were exploited to encapsulate the hydrophobic pesticide THI by self-assembly, and the size of the obtained nanoparticles, THI@BSA·NPs, was approximately 23 nm. The loading efficiency reached 70.4%, and THI@BSA·NPs could be released continuously for over 15 days, with the cumulative release reaching 93.5%. The fluorescein isothiocyanate (FITC)-labeled nanoparticles were evenly distributed in the digestive tract and body surface of a typical TBPs, M. alternatus, and the stomach and contact toxicities increased by 33.7% and 25.9%, respectively, compared with those of free THI. Furthermore, the results showed that the transport efficiency of THI@BSA·NPs was highest at a concentration of 50 µg/mL, and the THI@BSA·NPs content in the trunk, from to lower to higher layers, was 8.8, 8.2, 7.6, and 5.8 µg/g. At the same time, THI@BSA·NPs also exhibited high transport efficiency in dead trees. CONCLUSION: The transport efficiency and toxicity of the active ingredients are the key factors for the control of TBPs. This work provided idea for the application of biological delivery system encapsulated hydrophobic pesticides. The novel self-assembled THI@BSA·NPs have promising potential for sustainable control of TBPs.

Sublethal and transgenerational effects of sulfoxaflor on the demography and feeding behaviour of the mirid bug Apolygus lucorum.

Sulfoxaflor, the first commercially available sulfoximine insecticide, has been used for the control of sap-feeding insect pests such as plant bugs and aphids on a variety of crops. However, its sublethal effects on the mirid bug Apolygus lucorum, one of the key insect pests of Bt cotton and fruit trees in China, have not been fully examined. Here, we evaluated the demography and feeding behaviour of A. lucorum exposed to sulfoxaflor. The leaf-dipping bioassay showed that the LC10 and LC30 of sulfoxaflor against 3rd-instar nymphs of this insect were 1.23 and 8.37 mg L-1, respectively. The LC10 significantly extended the nymphal duration and decreased the oviposition period by 5.29 days and female fecundity by 56.99% in the parent generation (F0). The longer duration of egg, 5th-instar nymphs, preadult, and male adult longevity were observed in the F1 generation (F1) at LC10. At the LC30, the duration of egg and 1st-instar nymph, female adult longevity, and oviposition period of the F1 were significantly shorter, while the nymphal duration in the F0 and duration of 5th-instar nymphs, preadult survival rate, and male adult longevity in the F1 significantly increased. The net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) in the F1 were not significantly affected by these two concentrations, whereas the mean generation time (T) was lower at the LC30. Additionally, the probe counts and cells mixture feeding time were markedly lengthened by the LC10 and LC30, respectively, when A. lucorum nymphs exposed to sulfoxaflor fed on Bt cotton plants without insecticides. These results clearly indicate that sulfoxaflor causes sublethal effects on A. lucorum and the transgenerational effects depend on the tested concentrations.

Sublethal and transgenerational effects of dinotefuran on biological parameters and behavioural traits of the mirid bug Apolygus lucorum.

The mirid bug, Apolygus lucorum, has become a major pest of many crops and fruit trees since the widespread adoption of Bt cotton in northern China. Neonicotinoid insecticides, such as dinotefuran, applied to control this pest may show sublethal effects, but evidence for such effects is lacking. Here, we investigated the sublethal and transgenerational effects of dinotefuran on biological parameters and feeding behavioural traits of A. lucorum using the age-stage, two-sex life table and electrical penetration graphs (EPGs), respectively. The LC10 and LC30 of dinotefuran against 3rd-instar nymphs of A. lucorum were 14.72 and 62.95 mg L-1, respectively. These two concentrations significantly extended the development duration from 3rd-instar nymph to adult in parent generation (F0). LC30 also increased the oviposition period and male adult longevity and reduced nymphal survival rate in the F0. For offspring generation (F1), the egg duration, preadult duration, and total preoviposition period were significantly lower at LC10 than in the control, and the egg duration, duration of 4th-instar nymphs, preadult duration, oviposition period, and fecundity were also decreased at LC30. However, the four demographic parameters of F1 generation, namely, net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T), were not affected by dinotefuran. The significant differences in the number of probes and duration of each of four feeding waveforms failed to be detected when A. lucorum nymphs treated by dinotefuran feed on Bt cotton plants without insecticide exposure. Overall, the dinotefuran concentrations tested here have sublethal, but no transgenerational impacts on A. lucorum.

Enhanced nitrogen removal through marine anammox bacteria (MAB) treating nitrogen-rich saline wastewater with Fe(III) addition: Nitrogen shock loading and community structure.

Marine anammox bacteria (MAB) were used to treat nitrogen-rich saline wastewater with Fe(III) addition under nitrogen shock loading. Ammonia loading rate (ALR) and nitrite loading rate (NLR) gradually increased from 0.033 and 0.039 to 0.68 and 0.89 kg/(m3·d), respectively. With 5 mg/L Fe(III) addition, ammonia removal rate (ARR) and nitrite removal rate (NRR) reached maximal values of 0.56 and 0.60 kg/(m3·d), respectively. The value of ΔNO2--N/ΔNH4+-N was lower than theoretical ratio due to existing marine Feammox process. The growth rate of MAB was accelerated by Fe(III) and it dominated the reactor (27.70%). Besides, MAB were synergized with Marinicella and Caldithrix to achieve higher total nitrogen removal. Haldane model was proper to analyze and predict the effect resulting from nitrite on the activity of MAB under nitrogen shock loading. Overall, this study provides novel insights into the effect of Fe(III) on MAB treating nitrogen-rich wastewater.