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The effects of plant volatiles on parasitoids are important with regards to the tri-trophic interactions among host plants, insect herbivores, and their natural enemies. However, the effects of plant volatiles on the important parasitoid (Microplitis pallidipes Szepligeti; Hymenoptera: Braconidae) of noctuids have not been determined at the molecular, laboratory, and outdoor scales with complementary approaches. The odorant binding protein 8 of M. pallidipes (MpOBP8) with an open reading frame of 459 bp was cloned and successfully expressed in Escherichia coli (Eubacteriales: Enterobacteriaceae). The purified protein MpOBP8 had a relatively high binding capacity to the plant volatile β-ionone (Ki value was 28.86 μM) in the fluorescence competitive binding assay. Meanwhile, Y-tube olfactometer experiments indicated that β-ionone selectively attracts the parasitic wasp as the ratio of M. pallidipes selecting β-ionone vs. control was 2:1. Likewise, field screenhouse experiments verified the above results as the ratio of M. pallidipes selecting β-ionone vs. control was close to 2:1. This study suggested that β-ionone is a plant volatile that attracts the parasitoid M. pallidipes, and MpOBP8 may play a key role in the discrimination of M. pallidipes in searching for hosts via β-ionone. In general our results suggest that β-ionone has the potential to enhance the biocontrol effect of parasitoids on insect herbivores.

Plant-mediated effects on the susceptibility of insect herbivores to entomoviruses are well recognized, but the mechanisms by which plant secondary metabolites impact susceptibility are poorly understood. With widely targeted metabolomics analyses of three plants (Glycine max, Brassica oleracea, Ipomoea aquatica) that caused significant differences in caterpillar (Spodoptera exigua) viral susceptibility, we found four plant phenolics (genistein, kaempferol, quercitrin, coumarin) that increased susceptibility. Subsequently, we analyzed transcriptomes of caterpillars treated with nucleopolyhedrovirus (NPV) alone or with one the four plant phenolics to examine differences in metabolic pathways. We found that phenolic treatments caused significant differences in genes up-or-down regulating cytochrome P450, glutathione S-transferase and consistently caused significant down-regulation of the CXE18 gene regulating antennal esterase in caterpillars. This study found four phytochemicals can be potential candidate NPV synergist and sheds light on the mechanisms driving insect susceptibility to entomoviruses.

Host plants have an effect on the susceptibility of lepidopteran insects to nucleopolyhedrovirus (NPV), but the role of the protein in peritrophic membrane (PM) of larvae has not been investigated. We determined a key PM gene (SeIIM8 gene) in Spodoptera exigua (Hübner), which plays a role in protecting against NPV infection. Then we quantified the activity of chitin synthase (SeCHS), the content of insect intestinal mucin (SeIIM) and the expression of their genes in S. exigua fed one of four foods (artificial diet, Brassica oleracea (L.), Glycine max (L.), or Ipomoea aquatica (Forsskal)) with or without inoculation of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). Our results showed that the larval mortality was highest for NPV-infected with siRNA-injected larvae, intermediate for NPV-infected larvae, and lowest for uninfected larvae. The SeCHS activity, SeIIM content, and their relative gene expressions of S. exigua fed G. max or artificial diet were lower compared to caterpillars fed other diets. The relative SeCHS and SeIIM8 gene expression levels of larvae depended on the interaction of NPV treatment, diet, and time. This study concluded that plants affected the susceptibility of insects to NPV by altering the enzyme activity and gene expression of insects.

Increased biodiversity can make valuable contributions to food production and security around the world. The role of plant species diversity for “ecological intensification” of agriculture has been widely recognised, but the potential contribution of multi-trophic-level production systems, such as rice-fish co-culture, has received less attention. A continuous 4-year experiment (2015–2018) was conducted comparing rice-fish (yellow finless eel and loach) co-culture, and mono-rice planting practices on the Chongming Eco-island of China. During the experiment, pests (insect herbivores and weeds), arthropods, pesticides, grain and marketable fish yield were sampled, soil quality (available nitrogen, phosphorus and potassium, total nitrogen, organic matter content and pH) and rice grain quality (protein content, chalkiness, gel consistency, amylose content) were evaluated, and an economic analysis were performed. Fish decreased herbivore insect abundance by 24.07%, reduced weeds abundance, richness and biomass by 67.62, 62.01 and 58.88% respectively, increased invertebrate predator abundance by 19.48%, and reduced the need for pesticide by 23.4%. Co-culture practice produced an average economic values 10.33% higher than in the mono-rice farming. In addition, rice-fish co-culture enhanced both soil and rice quality. Our results confirm that rice-fish co-culture can be an effective form of ecological intensification, incorporating and contributing ecosystem services in agricultural production and increasing sustainability.

Plant‐insect herbivore‐entomopathogen interactions are one of the hot topics in biological control and humoral immunity, and biochemical metabolism are important responses of herbivores to pathogen infection. Entomopathogens are key biocontrol agents of caterpillars, but how plants affect the responses of caterpillars to these organisms is not well understood. We studied hormonal immunity (lysozyme and phenoloxidase activities) and biochemical metabolism (total protein and lipid contents) of Beauveria bassiana‐infected beet armyworm (Spodoptera exigua) larvae that feed on five different host plants (soya bean, Chinese cabbage, edible amaranth, water convolvulus and pepper). Results indicated that plant species differentially affected lysozyme and phenoloxidase activity and lipid content, but had no effect on protein content of pathogen‐infected caterpillars. Both lysozyme and phenoloxidase activities were generally higher in entomopathogen‐infected larvae that feed on edible amaranth or water convolvulus compared with the other three plants from days 1 to 5 after treatment. Plant species did not affect in regular changes during the 5 days in the lipid content of infected or non‐infected caterpillars. Our study reveals that plants fail to affect the biochemical metabolism but plants can mediate the humoral immunity of caterpillars to defend against pathogens. This study provides insight into plant‐mediated effects on the response of herbivores to pathogens.

Ecological niche indicators have been scarcely adopted to assess the biological control of insect herbivores by their natural enemies. We hypothesize that plant diversification promotes the biocontrol services by narrowing the niches of herbivores and broadening the niches of natural enemies. In a large-scale experiment, we found that the abundance of natural enemies was increased by 38.1%, and the abundance of insect herbivores was decreased by 16.9% in peach orchards with plant diversification (treatment) compared to ones with monoculture (control). Stratified sampling indicated that the horizontal, vertical, temporal and three-dimensional niches of natural enemies were generally broader while these niches of herbivores were narrower. Additionally, diverse plants give rise to an increase in the temporal synchrony and spatial similarity of the herbivores and natural enemies in peach orchards. Our study reveals that plant diversification promotes the biocontrol services by shaping the niche of herbivores and natural enemies, and provides a new assessment method to understand the biodiversity-niche-ecosystem management interactions.

The use of ground cover vegetation is becoming a prominent intervention for promoting biodiversity and associated ecosystem services in Chinese orchards. Despite the large number of studies that have examined the effects of ground cover vegetation on promoting natural enemy populations and related natural pest control, it is less understood whether enhanced natural pest control translates to increase yield and reduced pesticide use. We conducted a 2-year experiment comparing three cover vegetation (ryegrass, clover, and hairy vetch) practices versus a bare ground control in commercial pear orchards in the Yangtze River Delta of East China (YRDEC), China. Natural enemy density (predator and parasitoid abundance), invertebrate herbivore performance (piercing-sucking herbivore abundance and branch-boring and fruit-boring percentage), pesticide input and pear fruit yield were recorded. The results indicated that cover vegetation decreased herbivore abundance and boring percentage by 49.95 and 63.6% respectively, and thus decreased pesticide use by 26.10%. Meanwhile, we found that cover vegetation increased the abundance of natural enemies by 620.75%, and increased pear fruit yield by 6.82%. Piecewise structural equation modelling indicated that increased natural enemy densities, decreased herbivore performance and pesticide use, while increasing fruit yield. Our results confirm that the use of ground cover vegetations (especially with clover and hairy vetch) can promote ecological intensification and biological pest control in pear orchards.

Nucleopolyhedrovirus (NPV) and parasitic wasps are two important biological control agents of lepidoptera caterpillars, and the compatibility of parasitism and NPV infection remains a complicated process. In this study, we examined the effects of different learning experiences by the endoparasitoid Microplitis pallidipes on their ability to discriminate NPV-infected from healthy caterpillars (larvae of beet armyworm, Spodoptera exigua). Compared to the parasitoids with no prior host contact (control), parasitoids with oviposition experience with healthy caterpillars had shorter searching time, shorter attacking time, a greater number of attacks, higher parasitism rate and greater comprehensive discrimination ability to both non-infected and NPV-infected caterpillars. They also had a higher percentage of first attacks on non-infected caterpillars than NPV-infected caterpillars, and these differences were more obvious with increasing time post-virus-inoculation. However, the values of these six host-discrimination indicators on NPV-infected caterpillars were not significant between the control parasitoids and parasitoids with oviposition experience on NPV-infected caterpillars from hours 24 to 96 after virus inoculation. Compared to parasitoids with oviposition experience on healthy caterpillars, parasitoids with oviposition experience on NPV-infected caterpillars generally had longer searching time, longer attacking time, fewer attacks, lower parasitism rate, and lower comprehensive discrimination ability to both non-infected and NPV-infected caterpillars, and a lower percentage of first attacks on non-infected vs. NPV-infected caterpillars. These results suggest that experience with healthy hosts helps parasitoids distinguish NPV-infected caterpillars from healthy caterpillars, but that experience with NPV-infected caterpillars did not convey the same discrimination ability.

It has been reported that the susceptibility of insect herbivores to entomoviruses is affected by phytochemicals ingested during the acquisition of viral inoculum on the foliage of host plants. However, the relationship between this susceptibility and phytochemicals is poorly understood. To test this hypothesis of plant‐mediated effects on this susceptibility, we measured the effects of foliage from three plants, soybeans (Glycine max), collards (Brassica oleracea) and water convolvuluses (Ipomoea aquatica), on the susceptibility of larval beet armyworm (Spodoptera exigua) to nucleopolyhedrovirus (NPV), and analysed six foliar chemicals (total phenolics, peroxidase [POD], catalase [CAT], superoxide dismutase [SOD], endochitinase and exochitinase) in the three plants, respectively. The results of exponential modelling indicated that the LD₅₀ₛ (median lethal dose) of NPV to larvae increased with the increase in both phenolics and POD but declined with the increase in four other foliar chemicals, while the opposite trend was found between median lethal time (LT₅₀) of NPV and the six foliar chemicals. This study reveals that phenolics and POD decrease host susceptibility to the entomoviruses and that CAT, SOD, endochitinase and exochitinase increase this susceptibility.

Enhancing ground cover vegetation is an important agricultural practice that regulates herbivore and predator insects in agricultural landscapes. However, the effects of ground cover on the spatial distributions of these organisms have scarcely been explored. Our goal was to measure the effects of ground cover on the spatial aggregation and association of insect herbivores and predators, which might contribute to the control of herbivorous pests. We conducted our experiments in peach orchards at two sites in eastern China. The two sites have experimental units with ground cover treatments that created a heterogeneous landscape. We conducted a 2-year experiment to investigate the abundance and distribution of herbivores (leafhoppers) and predators (ladybirds), using geostatistics to analyze their spatial aggregation and association. The abundance of predators increased and that of herbivores decreased in ground cover orchards compared to control orchards without ground cover. The proportion of spatial structure was greater than 0.75 for both herbivores and predators in the control orchards, indicating a lack of spatial aggregation, and less than 0.75 in peach orchards with ground cover, indicating spatial aggregation. The correlation of spatial aggregation between herbivores and predators was significantly positive in the ground cover treatment, indicating association of the two insect guilds. In control orchards, on the other hand, this was not significant. The presence of ground cover increased predator abundance, spatial aggregation of herbivores and predators as well as their spatial association, suggesting a mechanism for more efficient control of herbivorous pests in peach orchards.

Microplitis pallidipes Szépligeti (Hymenoptera: Braconidae) is an important parasitic wasp of second and third-instar noctuid larvae such as the insect pests Spodoptera exigua, Spodoptera litura, and Spodoptera frugiperda. As in other insects, M. pallidipes has a chemosensory recognition system that is critical to foraging, mating, oviposition, and other behaviors. Odorant-binding proteins (OBPs) are important to the system, but those of M. pallidipes have not been determined. This study used PacBio long-read sequencing to identify 170,980 M. pallidipes unigenes and predicted 129,381 proteins. Following retrieval of possible OBP sequences, we removed those that were redundant or non-full-length and eventually cloned five OBP sequences: MpOBP2, MpOBP3, MpOBP8, MpOBP10, and MpPBP 429, 429, 459, 420, and 429 bp in size, respectively. Each M. pallidipes OBP had six conserved cysteine residues. Phylogenetic analysis revealed that the five OBPs were located at different branches of the phylogenetic tree. Additionally, tissue expression profiles indicated that MpOBP2 and MpPBP were mainly expressed in the antennae of male wasps, while MpOBP3, MpOBP8, and MpOBP10 were mainly expressed in the antennae of female wasps. MpOBP3 was also highly expressed in the legs of female wasps. Temporal profiles revealed that the expression of each M. pallidipes OBP peaked at different days after emergence to adulthood. In conclusion, we identified five novel odorant-binding proteins of M. pallidipes and demonstrated biologically relevant differences in expression patterns.Identification et profil d’expression des protéines de liaison aux odeurs chez la guêpe parasite Microplitis pallidipes à l’aide du séquençage à lecture longue PacBio.Microplitis pallidipes Szépligeti (Hymenoptera : Braconidae) est une importante guêpe parasite des larves de noctuelles de deuxième et troisième stades telles que les insectes ravageurs Spodoptera exigua, Spodoptera litura et Spodoptera frugiperda. Comme d’autres insectes, M. pallidipes possède un système de reconnaissance chimiosensoriel, essentiel à la recherche de nourriture, à l’accouplement, à la ponte et à d’autres comportements. Les protéines de liaison aux odeurs (PLO) sont importantes pour le système, mais celles de M. pallidipes n’ont pas été déterminées. Cette étude a utilisé le séquençage à lecture longue PacBio pour identifier 170 980 unigènes de M. pallidipes et prédit 129 381 protéines. Après la récupération des séquences de PLO possibles, nous avons supprimé celles qui étaient redondantes ou pas de pleine longueur et avons finalement cloné cinq séquences de PLO, MpOBP2, MpOBP3, MpOBP8, MpOBP10 et MpPBP, respectivement de taille 429, 429, 459, 420 et 429 pb. Chaque PLO de M. pallidipes avait six résidus de cystéine conservés. L’analyse phylogénétique a révélé que les cinq PLO étaient situés à différentes branches de l’arbre phylogénétique. De plus, les profils d’expression tissulaire ont indiqué que MpOBP2 et MpPBP étaient principalement exprimés dans les antennes des guêpes mâles, tandis que MpOBP3, MpOBP8 et MpOBP10 étaient principalement exprimés dans les antennes des guêpes femelles. MpOBP3 était également fortement exprimé dans les pattes des guêpes femelles. Les profils temporels ont révélé que l’expression de chaque PLO de M. pallidipes culminait à différents jours après l’émergence à l’âge adulte. En conclusion, nous avons identifié cinq nouvelles protéines de liaison aux odeurs de M. pallidipes et démontré des différences biologiquement pertinentes dans les profils d’expression.

One of the major drivers of global change is temperature elevation, which plays an important role in ecological interactions among species. However, it is still not known whether experimental temperature elevation promotes or inhibits the coexistence of multiple natural enemies of insect herbivores. We hypothesize that increased temperatures will favor synergisms among natural enemies. We examined the effects of temperature increases on an insect herbivore, beet armyworm ( Spodoptera exigua ) and its two most important natural enemy groups — parasitic wasps ( Microplitis pallidipes ) and entomoviruses (nucleopolyhedrovirus, NPV). Specifically, we examined the discriminatory response of parasitoids to NPV-infected and non-infected herbivores in the face of rising temperatures. Over a range of increasing temperature (19, 23, 27, 31 and 35 °C) and two virus dosages (5.33 × 10 7 and 5.33 × 10 5 OB·mL −1 ) at five different time periods (24, 48, 72, 84 and 96 h after treatment), both searching time and attacking time of parasitoids, to both NPV-infected and non-infected caterpillars, decreased with increasing temperatures. Consequently, the number of hosts attacked and the parasitism rates achieved by parasitoids increased. The percentage of first attacks by parasitoids that occurred in NPV-infected herbivores decreased with increasing temperature, with an increasing proportion of first attacks by parasitoids occurring, consequently, in uninfected caterpillars. Our study reveals that increased temperatures will make natural enemies more synergistic in the control of insect herbivores, and suggests that global warming might promote the coexistence of multiple natural enemies.

Plant–herbivore–entomopathogen tri-trophic interactions and biodiversity are relatively understudied topics in ecology. Particularly, the effects of entomopathogens on herbivore-induced plant volat...

Phenoloxidase (PO) catalyses the synthesis of o-quinones, which plays critical roles in the innate immunity of insects. The un-activated form of PO is prophenoloxidase (PPO), which has been widely reported, especially in connection with the immune response of insects to invading organisms or chemicals. However, connection between PPO and challenge by combinations of two biocontrol agents (parasitoids and virus) is not well known. We cloned the cDNA encoding an insect PPO (designated as SePPO1) from the beet armyworm, Spodoptera exigua (Hubner), and studied the response of SePPO to the challenge of Microplitis pallidipes Szepligeti and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). The results indicated that SePPO1 had an open reading frame of 2055 bp. Sequence alignment and phylogenetic analysis showed that SePPO1 shared 51% identity with SePPO2, and the two SePPO genes were positively correlated in mRNA levels, which indicated that they act synergistically. The two SePPOs were mainly e...

Spodoptera exigua nucleopolyhedrovirus (SeNPV) has been successfully applied as a bioinsecticide against S. exigua, one of the most devastating pests worldwide. However, due to limited information, the molecular mechanisms underlying interactions between S. exigua and SeNPV remain to be elucidated. In this study, RNA-Seq and differentially expressed gene (DEG) analysis of the S. exigua larva midgut were performed to explore molecular responses to SeNPV infection. A total of 1785 DEGs, including 935 upregulated and 850 downregulated genes, were identified in the midgut of SeNPV-infected S. exigua larvae. Ultrastructural observations showed that after SeNPV infection, the peritrophic matrix (PM) became a loose and highly porous surface with many clear ruptures; these changes were most likely associated with upregulation of chitin deacetylases. In addition, 124 putative innate immunity-related DEGs were identified and divided into several groups, including pattern recognition proteins, signaling pathways, signal modulation, antimicrobial peptides and detoxification. Interestingly, upregulation of some pattern recognition proteins, induction of the JAK/STAT signaling pathway and promotion of REPAT synthesis might be the main innate immunity responses occurring in the S. exigua larva midgut after SeNPV infection. According to quantitative real-time PCR, the expression profiles of 19 random DEGs were consistent with those obtained by RNA-Seq. These findings provide important basic information for understanding the molecular mechanisms of SeNPV invasion and the anti-SeNPV responses of the S. exigua midgut, promoting the utility of SeNPV as a bioinsecticide for the effective control of S. exigua and related pests.

We determined the effects of parasitism by Microplitis pallidipes and/or nucleopolyhedrovirus (NPV) infection on protective enzymes in the hemolymph of Spodoptera exigua larvae. We found that concentrations of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were constantly higher within the five observation days after treatment in parasitized/virus-infected than healthy (control) larvae. In parasitized + infected larvae, enzyme levels reduced from day 1 compared to parasitized larvae. Compared to enzyme levels in virus-infected larvae, in parasitized + infected larvae, CAT concentrations were generally lower, while SOD concentrations were significantly lower in the first two days and POD concentrations were lower in the first two days, but higher in following three days. We concluded that joint and separate parasitism and NPV infection promoted the activities of protective enzymes. Our findings also revealed that NPV infection inhibited the activities of protective enzymes induced ...

Nine-year data were collected to analyze the occurrence of rice planthoppers in diversified farming on Chongming Eco-Island in China from 2006 to 2014, the most important pests of rice in agroecosystems. We found a significantly linear decrease in the average numbers of adult rice planthoppers trapped per light trap per day. Using quadratic regression polynomial analysis we concluded that four meteorological indicators (average daily temperature, daily rainfall, sunshine duration, and average daily wind velocity) had significant effects on the numbers of brown planthopper ( Nilaparvata lugens ) and white-backed planthopper ( Sogatella furcifera ) trapped in the lamp, and that average daily temperature had a significant effect on the number of small brown planthopper ( Laodelphax striatella ) trapped in the lamp. These findings suggest that increasing temperature related to climate change might promote the occurrence of rice planthoppers in diversified farming in the future.

Increasing agricultural biodiversity by diversifying crops or by co-culture of crops and aquatic animals has been widely recognised as a way to promote ecological intensification of crop production and reduce the use of pesticides. However, the potential of multi-trophic-level production systems, such as the co-culture of vegetables, flowers and aquatic animals, has received little attention. We performed a two-year experiment comparing multispecies (cauliflower, taro, flowers and aquatic animals) co-culture, and mono-cauliflower farming practices on the Chongming Eco-island of China. The abundance of herbivorous insects and their predators, pesticide input and cauliflower yield were recorded. The results indicated that multispecies co-culture decreased the abundance of insect herbivores by 19.9–26.0% and thus decreased pesticide use by 22.2–30.0%. Meanwhile, we found that co-culture of crops, flowers and aquatic animals increased the abundance (29.5–34.1%), and species diversity of invertebrate predators (3.3–3.8%), and increased cauliflower yield (6.9–7.5%). There were significant positive relationships between the abundance, species richness (or diversity) of arthropod predators and cauliflower yield. Multispecies co-culture has great potential to promote ecological intensification of vegetable production and the associated ecosystem services.

We determined the effects of parasitism by the endoparasitoid Microplitis pallidipes Szepligeti and/or nucleopolyhedrovirus (NPV) infection on hemocyte apoptosis of Spodoptera exigua (Hübner) larvae. Compared to healthy (control) larvae, larvae that were parasitized, virus-infected, or both all showed a significant increase in hemocyte apoptosis during 48-h observation period. The peaks of hemocyte apoptosis in parasitized, virus-infected and parasitized+infected larvae were at 12, 24 and 48 h after treatment, and were 86.7±1.9, 87.4±3.6 and 76.5±1.6%, respectively. Meanwhile, compared to parasitized larvae, hemocyte apoptosis in jointly parasitized and infected larvae increased by 12.9%, 18.7% and 2.8% at 8, 36 and 48 h respectively, and decreased by 39.0% and 9.1% at 12 and 24h. Compared to virus-infected larvae, hemocyte apoptosis in jointly parasitized and infected larvae increased by 13.4%, 2.4% and 15.3% at 8, 36 and 48 h, respectively, and decreased by 4.0% and 29.9% at 12 and 24h. Our study found that joint and separate parasitism and SeNPV infection induced hemocyte apoptosis of S. exigua larvae. It also revealed that NPV infection promoted host hemocyte apoptosis induced by parasitism at early egg and larval stages of M. pallidipes in host larvae, but inhibited the same effect at late egg stage of M. pallidipes in host larvae, and that parasitism promoted host hemocyte apoptosis induced by NPV infection at early egg and larval stages of M. pallidipes in host larvae, but inhibited the same effect at late egg stage of M. pallidipes in host larvae.

The physiological effects of nucleopolyhedrovirus (NPV) infection and parasitism by Microplitis pallidipes (Hymenoptera: Braconidae) on the hemocytes of Spodoptera exigua (Lepidoptera: Noctuidae) larvae were examined. We found that compared to healthy (control) larvae, the total hemocyte count (THC) and granulocyte count in parasitized larvae increased 1 day after parasitization and then decreased, while the plasmatocyte count was not significantly affected for the first 5 days but was significantly enhanced on day 6 after parasitization. In parasitized + infected larvae, both the THC and granulocyte counts began be lower from day 1 compared to parasitized larvae, while the plasmatocyte count was generally lower than in parasitized larvae. Compared to the control, THC, and granulocyte counts of virus-infected larvae were higher 1 day after infection. Compared to that in virus-infected larvae, THC and granulocyte counts in parasitized + infected larvae began to decrease from day 1 while the plasmatocyte co...

The extensive input of chemical insecticides for pest control is considered as a serious risk to the environment, and the ecological disturbance of chemical insecticides has both positive and negative effects on complex agro-ecosystems. This paper proposed an indicator based on ecological two-sidedness theory and Shannon entropy, which is intended for analyzing informational complexity in a decision network of the chemical insecticide pollution management. The results indicated that the order of the value of R CC/CP index (where the R CC/CP index matrix W CC/CP is defined as the index optimization matrix of comprehensive cost divided by the index optimization matrix of comprehensive profit) for three insect pest-controlling strategies in scallion fields was “applying frequency vibration lamps and environment-friendly insecticides 8 times” (0.8714)

This study examined the physiological effects of joint and separate parasitism and infection by the endoparasitoid Microplitis pallidipes Szepligeti and the nucleopolyhedrovirus (NPV), respectively, on haemolymph 20-hydroxyecdysone (20-E) titre in Spodoptera exigua (Hubner) larvae. The results indicated that in parasitized larvae, virus-infected larvae (5.7 × 103 and 5.7 × 105 OB/ml) and parasitized larvae infected with virus at 5.7 × 105 OB/ml, compared to healthy larvae, the 20-E all declined during the first 3 days but began to increase from day 4 after treatment, while in jointly parasitized and infected larvae (5.7 × 103 OB/ml), the 20-E declined during the first 4 days but began to increase on day 5 after treatment. Meanwhile, compared to parasitized larvae, the 20-E declined during the first 4 days but significantly increased on day 5 in jointly parasitized and infected larvae (5.7 × 103 OB/ml), while significantly increased during the first 2 days but began to decrease from day 3 after treatment in jointly parasitized and infected larvae (5.7 × 105 OB/ml). Finally, in larvae that were both parasitized and virus infected (5.7 × 103 OB/ml), compared to just virus-infected larvae (5.7 × 103 OB/ml), the 20-E was lower on days 3 and 4 but higher on other days after treatment; in larvae that were both parasitized and virus infected (5.7 × 105 OB/ml), compared to just virus-infected larvae (5.7 × 105 OB/ml), the 20-E was significantly higher at the first 2 days but lower from day 3 after treatment. Our results revealed that 2nd instar larval M. pallidipes in host bodies may release 20-E into the haemolymph of S. exigua larvae and that NPV infection may stimulate S. exigua to release more 20-E during its third to fourth instar larval moulting. We found that this stimulatory effect was greater with higher virus concentrations.

Ecological engineering of ground cover vegetation in agro-ecosystem may affect the diversity and stability of arthropod communities. Factors affecting the stability of arthropod community in turn influence the relationship between arthropod diversity and stability, which has been rarely investigated. We conducted a 2-year field-experiment in Shanghai and Jiangsu province in eastern China, examining the effects of the ecological engineering of ground cover plant Trifolium repens on the diversity and stability of canopy arthropod community in peach orchards. The results indicated that five diversity indices (abundance, species richness, Simpson's index, Shannon–Wiener index and Pielou's evenness index) and four stability indices ( N n /N p , S n / S p , ( N n + N d )/ N p and ( S n + S d )/ S p ) were all significantly higher but the coefficient of variation ( d s / d m ) was significantly lower in ground cover areas than control areas. The results of Pearson's correlations were significantly negative for abundance/richness and the above four stability indices both in ground cover areas and control ones in both sites; correlations between Pielou evenness index and the above four stability indices were all positive in control areas, while those in ground cover areas were not the same. Our study provides a more comprehensive understanding for arthropod community stability, suggesting that regulating harmful arthropods by beneficial and neutral arthropods was the basic implication of arthropod stability, and demonstrates that the ecological engineering of ground cover T . repens can enhance the diversity and stability of canopy arthropod communities but increased arthropod diversity will not always positively affect arthropod stability.

The behaviour and oviposition of solitary endoparasitoid Microplitis pallidipes Szepligeti (Hymenoptera: Braconidae) were monitored to investigate the ability of the parasitoids to distinguish between nucleopolyhedrovirus (NPV)-infected and noninfected Spodoptera litura Fabricius (Lepidoptera: Noctuidae) larvae. The results indicated that the parasitoid searching time and the time until the first parasitoid attack on infected larvae were greater than those recorded on noninfected larvae; the number of infected larvae attacked by parasitoids, the percent of first attacks and parasitism rate in infected larvae were lower than those on noninfected larvae; and these differences were all significant 3 to 5 days postexposure of the larvae to a dose of 1.6 × 108 occlusion bodies (OB)· ml−1 and significant 4 and 5 days postexposure of the larvae to a dose of 1.6 × 107 OB·ml−1. The lowest dosage (1.6 × 106 OB·ml−1) had no significant effect on the above index values. In a field cage experiment, we found that the p...

We conducted a 2-year field experiment at two sites in eastern China, examining the effects of the ground cover by Trifolium repens L. on the biocontrol services in peach orchards. The results indicated that compared to those in control areas, the abundances of aphids and Grapholitha molesta decreased, respectively, by 31.4% and 33.3% in Shanghai and by 30.1% and 33.3% in Jiangsu, while the abundance of generalist arthropod predators increased by 116.7% in Shanghai and by 115.8% in Jiangsu in ground cover areas. Compared to that in control areas, the ratio of generalist predator abundance to aphid abundance and to G. molesta abundance increased, respectively, by 260.0% and 384.2% in Shanghai and by 213.3% and 253.1% in Jiangsu in ground cover areas. Our study revealed that the ecological engineering of ground cover by T. repens promoted biocontrol services in peach orchards.

Global societies witnessed rapid increase in population and accelerating demand for vegetables from cities along the coastal areas (e.g., Shanghai). Development of “multiculture”, “polyculture”, or “co-culture” systems along the coastal areas in Southeast Asia in turn become a preferred choice for installing future aquaculture. To build much needed knowledge guiding the design, ecological benefits, and performances of these newly explored vegetable-aquaculture systems, we designed a nested block experiment and conducted a 3-year study of cauliflower-aquaculture farming on the island. We found that farming type significantly affected the arthropod herbivores and predators, including herbivore abundance and the abundance, species richness and Shannon's diversity of the predators. More importantly, farming type had a significant effect on insecticide use, cauliflower yield and economic returns. The reduction in insecticide use promoted predator diversity and cauliflower yield in co-cultured cauliflower aquaculture as indicated by a significantly negative relationship between amount of commercial insecticides and arthropod predator diversity, as well as between amount of commercial insecticide and cauliflower yield. We conclude that co-culture practice in cauliflower-aquaculture enhanced agricultural production while decreasing use of insecticide and herbivore abundance, and increasing the abundance and diversity of predators, vegetable yield and economic value.

For this study we collected eight years (2006–2013) of data on Chongming Eco-island in China, analyzing the effects of large-scale agriculture on the occurrence of the rice leaf roller, Cnaphalocrocis medinalis Guenee, a dominant foliage feeder in rice ecosystems. We found that the peak of the C . medinalis population was obvious in 2006, 2007 and 2009, with more than 400 adult C . medinalis trapped in a single insecticidal lamp each day and more than 500 individuals per 66.7 m 2 in paddy field. We found a significantly positive correlation between the number of adult C . medinalis trapped in the lamp and the number of moths observed in the paddy field and these two monitoring indicators of C . medinalis were both significantly influenced by average daily temperature. Our study suggests that global warming might promote the occurrence of C . medinalis in large-scale agriculture in the future.

Using multiple pest-mortality sources is a basic tenet of IPM, but they may not always be compatible. To that end, we examined compatibility of parasitism and nucleopolyhedrovirus (NPV) infected. Specifically, we examined the effects of prior oviposition experience by Microplitis pallidipes on its ability to distinguish NPV-infected from healthy larvae of Spodoptera litura. We found that time spent searching for hosts was significantly lower, while the number of attacks, percentage of first attacks, and parasitism rate were all significantly higher in healthy versus virus-infected hosts for parasitoids that had experienced healthy hosts. Meanwhile, parasitoids that had experienced infected hosts spent significantly more time searching for infected hosts starting on day 2. For these parasitoids, the number of attacks, percentage of first attacks, and parasitism rate were all significantly lower from day 2 in virus-infected versus healthy larvae. We found no significant differences between parasitoids without experience versus ones experienced with infected hosts in search time for infected hosts, number of infected host attacks, or percentage of first attacks on infected hosts. In comparison, parasitoids that had experienced healthy hosts spent less time searching for healthy hosts than parasitoids without experience, and displayed a higher frequency of attack on healthy hosts and a higher percentage of first attacks on healthy hosts. Experience with healthy larvae aided parasitoids in distinguishing healthy from virus-infected larvae, but experience with virus-infected larvae did not convey the same discrimination. This information provides a better understanding of how to integrate NPV applications with naturally occurring parasitism for this pest in crops.

We determined the physiological effects of joint and separate nucleopolyhedrovirus (NPV) infection and parasitism by the endoparasitoid Microplitis pallidipes Szepligeti on biochemical events in the noctuid Spodoptera exigua (Hubner). The results indicated that in parasitized larvae, compared to healthy larvae, total protein concentration in host hemolymph began to decline and total sugar concentration significantly increased by the first day, while lipid content in the host body significantly increased by the second day after parasitization. Meanwhile, in jointly infected and parasitized hosts, compared to parasitized larvae, total protein concentration was consistently higher, total sugar concentration was consistently lower, and lipid content became higher by the second day after treatment. In virus-infected larvae, compared to healthy larvae, total protein concentration sharply declined during the first two days but increased by the third, while total sugar concentration increased on the second and third days after virus infection but decreased at other observation times, and lipid content began to increase by the second day after virus infection. Finally, in larvae that were both parasitized and virus-infected, compared to just virus-infected larvae, total protein concentration increased during the first two days but decreased by the third, total sugar concentration increased only on the first and fourth days, and lipid content decreased significantly on the first day but began to increase by the second day after treatment. These findings led us to conclude that parasitization inhibited protein mobilization but stimulated sugar mobilization in host hemolymph, and promoted lipid mobilization in the host body, while Spodoptera exigua NPV infection stimulated protein mobilization induced by parasitization but inhibited sugar mobilization induced by parasitization.

Human inputs into complex agro-ecosystems, such as those involving rice production, have ecological, economic, and social effects that can be positive or negative. We here described positive effects using the term comprehensive profit (CP), which included ecological, economic and social profits. The negative effects are termed comprehensive cost (CC), including ecological, economic and social losses. To develop an eco-engineering assessment system based on these parameters, we used a matrix of the ratios of comprehensive cost to comprehensive profit (RCC/CP), where the RCC/CP index matrix WCC/CP is defined as the index optimization matrix of CC divided by the index optimization matrix of CP. We applied the basic principles and methods of Analytic Hierarchy Processes (AHP) to determine the comparative weight of indices derived in this manner as the basis for identifying one or more pesticide pollution management strategies for use in rice production systems in Shanghai, China. We used a generalized function to nondimensionalize the value of the index, and then to calculate the systematic evaluation index. The evaluating result range for CP used for this purpose was classified into 5 levels: excellent, better, general, bad and worst, as was the range for CC (very high, much high, common, much low and very low). Applying our assessment system (RCC/CP) for five different pest control strategies in rice fields gave the order of value of the strategies to be: “applying environment-friendly pesticides 6 times and frequency vibration lamps with rice–milk vetch rotation mode” (0.744) < “applying environment-friendly pesticides 5 times and frequency vibration lamps with rice–milk vetch rotation mode” (0.747) < “applying environment-friendly pesticides 5 times and postponing transplanting date with rice–milk vetch rotation mode” (0.753) < “applying environment-friendly pesticides 6 times and postponing transplanting date with rice–milk vetch rotation mode” (0.760) < “applying common pesticides 9 times and following conventional transplanting date with rice–wheat rotation” (0.930). The treatment “applying environment-friendly pesticides 6 times and frequency vibration lamps with rice–milk vetch rotation mode” was determined to be the optimal chemical pollution management strategy for use in rice fields in Shanghai, China.

The extensive use of synthetic chemicals for pest control is recognized as a major threat to ecosystem integrity and the realization of low-carbon agriculture. There have been many studies of agrochemical reduction technologies, but little work to date has been done to achieve a combined reduction of chemical pesticides and chemical fertilizers. This fact has led us to the conception of assessment methodologies and the establishment of a relevant ecological model. A significant challenge to the development of assessment methodologies is agro-ecosystem complexity. In this study, we explain the agro-ecosystem as one composed of various social, economic and natural factors that can be defined using a comprehensive positive/negative effect evaluation index system, which is based on fuzzy theory and can be used to assess combinations of technologies for reduced use of chemical pesticides and fertilizers in cauliflower fields. On this basis, a technology using 14% calcium superphosphate 750 kg hm −2 , 46% urea 825 kg hm −2 , 12% granular boron fertilizer 4.5 kg hm −2 , active pesticides 3.09 kg hm −2 and hanging sex pheromone lure on the watermelon–cauliflower rotation mode resulted in the largest index evaluation value (0.3795) and was considered the best combined reduction technology in Chongming Eco-island, Shanghai of China. The results of our study should be of interest to policy makers and environmental managers who seek to realize low-carbon agriculture and to farmers who seek to optimize application technology in practice.

After investigation and analysis of the practice of pesticide application in the protected horticultural fields of the Agricultural Experimental Zone in Pudong district, Shanghai , China, analytic hierarchy process (AHP) was applied to evaluate 5 alternative pest-control strategies (including three gray insect-proof net rooms (with mesh) of different height, white insect-proof thin film rooms (without mesh) and normal control and prevention areas (without any covering nets or thin films)). Comprehensive Profit (CP) and Comprehensive Cost (CC) were used in this paper to analyze the superiority of different strategies in protected horticultural fields for pest management. CP and CC of the pest-control strategies were used as the targets of AHP, in which CP was classified into economic, social and ecological profit, while CC was split into economic, social and ecological cost. Ratio of Comprehensive Cost to Comprehensive Profit (RCCCP) was calculated by dividing Comprehensive Cost (CC) by Comprehensive Profits (CP). According to the analysis, the best strategy was to apply gray insect-proof net rooms of 2.2 m high and 360 (12 m × 30 m) square meters in protected horticultural fields for pest management.

While the worldwide standardization of agricultural production has been advocated and recommended, relatively little research has focused on the ecological significance of such a shift. The ecological concerns stemming from the standardization of agricultural production may require new methodology. In this study, we concentrated on how ecological two-sidedness and ecological processes affect the standardization of agricultural production which was divided into three phrases (pre-, mid- and post-production), considering both the positive and negative effects of agricultural processes. We constructed evaluation indicator systems for the pre-, mid- and post-production phases and here we presented a Standardization of Green Production Index (SGPI) based on the Full Permutation Polygon Synthetic Indicator (FPPSI) method which we used to assess the superiority of three methods of standardized production for peaches. The values of SGPI for pre-, mid- and post-production were 0.121 (Level IV, “Excellent” standard), 0.379 (Level III, “Good” standard), and 0.769 × 10−2 (Level IV, “Excellent” standard), respectively. Here we aimed to explore the integrated application of ecological two-sidedness and ecological process in agricultural production. Our results are of use to decision-makers and ecologists focusing on eco-agriculture and those farmers who hope to implement standardized agricultural production practices.

The extensive use of chemical pesticides for pest management in agricultural systems can entail risks to the complex ecosystems consisting of economic, ecological and social subsystems. To analyze the negative and positive effects of external or internal disturbances on complex ecosystems, we proposed an ecological two-sidedness approach which has been applied to the design of pest-controlling strategies for pesticide pollution management. However, catastrophe theory has not been initially applied to this approach. Thus, we used an approach of integrating ecological two-sidedness with a multi-criterion evaluation method of catastrophe theory to analyze the complexity of agro-ecosystems disturbed by the insecticides and screen out the best insect pest-controlling strategy in cabbage production. The results showed that the order of the values of evaluation index (RCC/CP) for three strategies in cabbage production was “applying frequency vibration lamps and environment-friendly insecticides 8 times” (0.80) < “applying trap devices and environment-friendly insecticides 9 times” (0.83) < “applying common insecticides 14 times” (1.08). The treatment “applying frequency vibration lamps and environment-friendly insecticides 8 times” was considered as the best insect pest-controlling strategy in cabbage production in Shanghai, China.

Many studies have supported the enemies hypothesis, which suggests that natural enemies are more efficient at controlling arthropod pests in polyculture than in monoculture agro-ecosystems. However, we do not yet have evidence as to whether this hypothesis holds true in peach orchards over several geographic locations. In the two different geographic areas in eastern China (Xinchang a town in the Shanghai municipality, and Hudai, a town in Jiangsu Province) during a continuous three-year (2010–2012) investigation, we sampled arthropod pests and predators in Trifolium repens L. and in tree canopies of peach orchards with and without the ground cover plant T. repens. No significant differences were found in the abundances of the main groups of arthropod pests and predators in T. repens between Hudai and Xinchang. The abundance, richness, Simpson's index, Shannon-Wiener index, and Pielou evenness index of canopy predators in ground cover areas increased by 85.5, 27.5, 3.5, 16.7, and 7.9% in Xinchang, and by 87.0, 27.6, 3.5, 17.0 and 8.0% in Hudai compared to those in the controls, respectively. The average abundance of Lepidoptera, Coleoptera, Homoptera, true bugs and Acarina canopy pests in ground cover areas decreased by 9.2, 10.2, 17.2, 19.5 and 14.1% in Xinchang, and decreased by 9.5, 8.2, 16.8, 20.1 and 16.6% in Hudai compared to that in control areas, respectively. Our study also found a higher density of arthropod species resources in T. repens, as some omnivorous pests and predators residing in T. repens could move between the ground cover and the orchard canopy. In conclusion, ground cover in peach orchards supported the enemies hypothesis, as indicated by the fact that ground cover T. repens promoted the abundance and diversity of predators and reduced the number of arthropod pests in tree canopies in both geographical areas.

A comparative study was conducted on the arthropod community in peach orchards with and without ground cover vegetation. In the orchard with ground cover vegetation, the individuals of beneficial, neutral, and phytophagous arthropods were 1.48, 1.84 and 0.64 times of those in the orchard without ground cover vegetation, respectively, but the total number of arthropods had no significant difference with that in the orchard without ground cover vegetation. The species richness, Shannon's diversity, and Pielou's evenness index of the arthropods in the orchard with ground cover vegetation were 83.733 +/- 4.932, 4.966 +/- 0.110, and 0.795 +/- 0.014, respectively, being significantly higher than those in the orchard without ground cover vegetation, whereas the Berger-Parker's dominance index was 0.135 +/- 0.012, being significantly lower than that (0.184 +/- 0.018) in the orchard without ground cover vegetation. There were no significant differences in the stability indices S/N and Sd/Sp between the two orchards, but the Nn/Np, Nd/Np, and Sn/Sp in the orchard with ground cover vegetation were 0.883 +/- 0.123. 1714 +/- 0.683, and 0.781 +/- 0.040, respectively, being significantly higher than those in the orchard without ground cover vegetation. Pearson's correlation analysis indicated that in the orchard with ground cover vegetation, the Shannon's diversity index was significantly negatively correlated with Nd/Np, Sd/Sp, and S/N but had no significant correlations with Nn/Np and Sn/Sp, whereas in the orchard without ground cover vegetation, the diversity index was significantly positively correlated with Nn/Np and Nd/Np and had no significant correlations with Sd/Sp, Sn/Sp, and S/N.