Aphid Development Research Articles

Effects of saline-alkali stress on cotton growth and physiochemical expression with cascading effects on aphid abundance.

Environmental stresses, such as soil salinity or alkalinity, usually affect crop growth and secondary plant metabolism, with follow on effects on foliar-feeding insects. Nevertheless, the underlying mechanism of how saline-alkali stress affects the key cotton pest Aphis gossypii Glover is poorly understood. In this study, we first considered effects of three types of saline-alkali stress (i.e., salinity alone, alkalinity alone - both at different concentration - and their mixed effects) on cotton plants. We then measured impacts of stress on (1) above and below plant growth traits (e.g., plant height, leaf area, root volume), (2) levels of nutrients and secondary metabolites in cotton leaves, and (3) feeding behavior, life-table parameters, and population growth of A. gossypii. We then used a path analysis to evaluate cascading effects of changes in plant growth (due to stress) and changes in levels of nutrients or secondary metabolites on growth of individual cotton aphids and aphid populations. We found either salinity or alkalinity stresses significantly reduced cotton growth, increased the content of tannin, soluble sugars, and proline in the leaves, and suppressed aphid growth and development, (including longevity, fecundity, and intrinsic rate of increase) and aphid population growth. Alkalinity had stronger effects on these traits than did salinity. This work provides insights into the bottom-up interaction mechanism by which these environmental stresses mediate aphid infestation levels in the cotton agricultural ecosystem.

De Novo Transcriptome Profiling of Mustard Aphid (Lipaphis erysimi) and Differential Expression of Transcripts Associated with Feeding and Non-Feeding Conditions and Developmental Stages.

Lipaphis erysimi is a specialist aphid of the Indian subcontinent that causes significant yield losses in oilseed Brassicas. Several aphid genes have been used as preferred targets in RNAi-based transgenic plants for aphid resistance. In order to enhance the repertoire of potential target genes for aphid control and to identify the genes associated with aphid feeding and development, we performed a two-way comparative study of differential gene expression profiles between (i) feeding and non-feeding adults and (ii) adult and nymph developmental stages of L. erysimi. De novo RNA-seq of aphids using Illumina technology generated a final transcriptome comprising 52,652 transcripts. Potential transcripts for host selection, detoxification, salivary proteins and effectors, molecular chaperones and developmental genes were identified. Differential gene expression studies identified variations in the expression of 1502 transcripts between feeding and non-feeding adults and 906 transcripts between nymphs and adults. These data were used to identify novel target genes for RNAi-based aphid control and facilitate further studies on the molecular basis of aphid feeding and development.

Adsorption of dinotefuran using TpBDMe COF nanoparticles for soil leaching reduction and bee safety

Dinotefuran (DIN) contaminates groundwater and is toxic to bees, so designing a novel pesticide loading system for dinotefuran is of great significance. In this paper, dinotefuran was loaded into TpBDMe COF with a mesoporous hollow structure, and the TpBDMe COF loaded with dinotefuran exhibited initial burst and subsequent sustained release behavior. The results showed that the product effectively suppresses wheat aphid development, with virtually no infestation occurring for 7–14 days, whereas other commercially available formulation had lost their usefulness. Our TpBDMe COF carrier effectively immobilizes dinotefuran, reducing pesticide leaching in soil by 70 % and enhancing the application efficiency of neonicotinoid insecticides. The LD50 of this product for acute exposure of honey bees doubled the LD50 of the original furosemide at 24 h and was equally effective at 48 h, reducing the toxicity to bees and promoting ecological safety. The results of this work show that this nanocarrier system is highly stable, loadable, insecticidal active, and environmentally friendly, showing great potential in the development of new nanocarriers for use.

Seasonal dynamics of cereal aphid population

Goal. To compare the seasonal dynamics of cereal aphid abundance in the Steppe and Forest-Steppe zones during 2023 and to determine the factors that influenced it. Methods. To assess the state of the cereal aphid population on cereal crops, we used the results of personally conducted entomological phytosanitary monitoring of crops (according to generally accepted methods) in the farms of the Steppe and Forest-Steppe zones; information from current reports from the places where field experiments were conducted directly by the forecasting laboratory, as well as other laboratories of the IPP of NAAS, which is also confirmed by the materials of decadal reports of regional plant protection stations and signalization and forecasting points of the State Inspection of Plant Protection, confirmed by information on the phytosanitary status of regional state research stations. Cereal aphid adults and larvae were counted in populations of populations (in the crop phase, the end of the tube emergence is earing). Results. The state of cereal aphid populations on crops of cereal spiked crops in 2023 was studied, both in general in Ukraine and separately in the Steppe and Forest-Steppe zones. The dynamics of their number in farms of different natural and climatic zones was investigated, and an analysis of its peculiarities in the conditions of the year was carried out. Conclusions. In 2023, the harmfulness of cereal aphids on cereal crops remained at the level of long-term averages. The expansion of their harmful zone and an increase in their number was noted during the earing period (milk ripeness). On winter cereal crops, phytophages prevailed in the Steppe zone. In the Forest-Steppe zone, the phytophage was more damaging to winter cereals than to spring cereals. The results of entomological monitoring in Mykolaiv region (State Enterprise «Experimental Farming «Zori nad Bugom») showed that during the accounting period the bulk of aphids were concentrated on winter wheat crops, and winter barley was damaged in small numbers. On the contrary, the surveys conducted in Kyiv region (State Enterprise «Experimental Farming «Salyvonkivske») showed that in the second half of June — the first decade of July, the number of aphids on spring barley crops was approximately twice as high as on spring wheat. As a result of the study, it was practically confirmed that the optimal temperature regime for the development of cereal aphids is 16—20°C, and the relative humidity is 60—80%.

Spread of Aphis gossypiiGlover, 1877 on cotton plants

A study was conducted on the distribution of the cotton aphid Aphis gossipy glow on various varieties and hybrids of cotton. The work was carried out during 2021-2023. The entomological part of the study included the study of the phenological development of cotton aphids, the study of their colonization and harmfulness. The yield of overripe cotton varieties was also studied. Information about the experiments performed is provided. The identified lines, hybrids and varieties of cotton have been identified and can be used to create new varieties of cotton.

DNA methylation machinery is involved in development and reproduction in the viviparous pea aphid (Acyrthosiphon pisum).

Epigenetic mechanisms, such as DNA methylation, have been proposed to mediate plastic responses in insects. The pea aphid (Acyrthosiphon pisum), like the majority of extant aphids, displays cyclical parthenogenesis - the ability of mothers to switch the reproductive mode of their offspring from reproducing parthenogenetically to sexually in response to environmental cues. The pea aphid genome encodes two paralogs of the de novo DNA methyltransferase gene, dnmt3a and dnmt3x. Here we show, using phylogenetic analysis, that this gene duplication event occurred at least 150 million years ago, likely after the divergence of the lineage leading to the Aphidomorpha (phylloxerans, adelgids and true aphids) from that leading to the scale insects (Coccomorpha) and that the two paralogs are maintained in the genomes of all aphids examined. We also show that the mRNA of both dnmt3 paralogs is maternally expressed in the viviparous aphid ovary. During development both paralogs are expressed in the germ cells of embryos beginning at stage 5 and persisting throughout development. Treatment with 5-azactyidine, a chemical that generally inhibits the DNA methylation machinery, leads to defects of oocytes and early-stage embryos and causes a proportion of later stage embryos to be born dead or die soon after birth. These phenotypes suggest a role for DNA methyltransferases in reproduction, consistent with that seen in other insects. Taking the vast evolutionary history of the dnmt3 paralogs, and the localisation of their mRNAs in the ovary, we suggest there is a role for dnmt3a and/or dnmt3x in early development, and a role for DNA methylation machinery in reproduction and development of the viviparous pea aphid.

The cuticular protein gene ApCP7 and ApCP62 are essential for reproduction in Acyrthosiphon pisum, affecting ecdysis and survival

Cuticular proteins, in conjunction with chitin, compose the insect exoskeleton, and play a key role in the growth, development, and molting of insects. However, the specific functions of most cuticular protein genes in the growth, development, and reproductive processes of the pea aphid (Acyrthosiphon pisum) remain unclear. In this study, we have identified six cuticular protein genes in the pea aphid, namely ApCP7, ApCP10, ApCP19, ApCP19.8-like, ApCP35 and ApCP62. We found that the expression levels of six genes were highly expressed during the adult stage, and except for ApCP10, which is highly expressed in the pea aphid cuticle, other genes were highly expressed in the ovaries. Subsequently, we observed that the survival rate and fecundity of pea aphid were significantly lower than those of the control group after silencing ApCP7 and ApCP62 through RNA interference. Furthermore, when ApCP7 transcript levels were reduced, aphid encountered difficulties in molting, were smaller in body size, and exhibited a darker body color. These results indicate that ApCP7 and ApCP62 are involved in the development and reproduction of pea aphid, and could be used as RNAi targets for controlling pea aphid.

Salinity stress alters plant-mediated interactions between above- and below-ground herbivores

Below-ground herbivory impacts plant development and often induces systemic responses in plants that affect the performance and feeding behavior of above-ground herbivores. Meanwhile, pest-damaged root tissue can enhance a plant's susceptibility to abiotic stress such as salinity. Yet, the extent to which herbivore-induced plant defenses are modulated by such abiotic stress has rarely been studied. In this study, we examine whether root feeding by larvae of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae) affects the performance of the above-ground, sap-feeding aphid Aphis gossypii (Hemiptera: Aphididae) on cotton, and assess whether those interactions are modulated by salinity stress. In the absence of salinity stress, A. segetum root feeding does not affect A. gossypii development. On the other hand, under intense salinity stress (i.e., 600 mM NaCl), A. segetum root feeding decreases aphid development time by 16.1 % and enhances fecundity by 72.0 %. Transcriptome, metabolome and bioassay trials showed that root feeding and salinity stress jointly trigger the biosynthesis of amino acids in cotton leaves. Specifically, increased titers of valine in leaf tissue relate to an enhanced performance of A. gossypii. Taken together, salinity stress alters the interaction between above- and below-ground feeders by changing amino acid accumulation. Our findings advance our understanding of how plants cope with concurrent biotic and abiotic stressors, and may help tailor plant protection strategies to varying production contexts.

Plant-derived artificial miRNA effectively reduced the proliferation of aphid (Aphidoidea) through spray-induced gene silencing.

Aphids (Hemiptera: Aphididae) are notorious sap-sucking insects that rampantly threaten agricultural production worldwide. Current management against aphids in the field heavily relies on chemical pesticides, which makes economical and eco-friendly methods urgently needed. Spray-induced gene silencing (SIGS) offers a powerful and precise approach to pest management. However, the high costs and instability of double-stranded RNA (dsRNA) regulators applied for downstream RNA interference (RNAi) still limit this strategy. It remains uncertain if RNAi regulators applied in SIGS could extend to small RNA (sRNA), especially miRNA. We chose two sRNA sequences, miR-9b and miR-VgR, whose corresponding targets ABCG4 and VgR are both essential for aphid growth and development. The efficacy of these sequences was initially verified by chemically synthetic single-stranded RNA (syn-ssRNA). Through spray treatment, we observed a significantly decreased survival number and increased abnormality rate of green peach aphids fed on the host under laboratory conditions. Based on our previous study, we generated transgenic plants expressing artificial miR-9b (amiR-9b) and miR-VgR (amiR-VgR). Remarkably, plant-derived amiRNA exerted potent and long-lasting inhibitory efficacy with merely one percent concentration of chemical synthetics. Notably, the simultaneous application of amiR-9b and amiR-VgR exhibited superior inhibitory efficacy. We explored the potential use of sRNA-based biopesticide through SIGS while investigating the dosage requirements. To optimize this strategy, the utilization of plant-derived amiRNA was proposed. The results suggested that attributed to stability and durability, deploying amiRNA in pest management is a potential and promising solution for the field application. © 2024 Society of Chemical Industry.

Moderate nitrogen application facilitates Bt cotton growth and suppresses population expansion of aphids (Aphis gossypii) by altering plant physiological characteristics.

Excessive application of nitrogen fertilizer in cotton field causes soil and water pollution as well as significant increase of aphid population. Reasonable fertilization is an important approach to improve agricultural production efficiency and reduce agriculture-derived pollutions. This study was aimed to explore the effects of nitrogen fertilizer on the Bt cotton physiological characteristics and the growth and development of A. gossypii, a sap-sucking cotton pest. Five different levels of Ca(NO3)2 (0.0 g/kg, 0.3 g/kg, 0.9 g/kg, 2.7 g/kg and 8.1 g/kg) were applied into vermiculite as nitrogen fertilizer in order to explore the effects of nitrogen fertilizer on the growth and development of Bt cotton and aphids. The results showed that the medium level of nitrogen fertilizer (0.9 g/kg) effectively facilitated the growth of Bt cotton plant and suppressed the population expansion of aphids, whereas high and extremely high nitrogen application (2.7 and 8.1 g/kg) significantly increased the population size of aphids. Both high and low nitrogen application benefited aphid growth in multiple aspects such as prolonging nymph period and adult lifespan, enhancing fecundity, and improving adult survival rate by elevating soluble sugar content in host Bt cotton plants. Cotton leaf Bt toxin content in medium nitrogen group (0.9 g/kg) was significantly higher than that in high (2.7 and 8.1 g/kg) and low (0.3 g/kg) nitrogen groups, but Bt toxin content in aphids was very low in all the nitrogen treatment groups, suggesting that medium level (0.9 g/kg) might be the optimal nitrogen fertilizer treatment level for promoting cotton seedling growth and inhibiting aphids. Overall, this study provides insight into trophic interaction among nitrogen fertilizer levels, Bt cotton, and cotton aphid, and reveals the multiple effects of nitrogen fertilizer levels on growth and development of cotton and aphids. Our findings will contribute to the optimization of the integrated management of Bt cotton and cotton aphids under nitrogen fertilization.

Understanding the onion aphid Neotoxoptera formosana's (Hemiptera: Aphididae) interaction with Allium (Asparagales: Amaryllidaceae) crops: a comprehensive study of feeding patterns and life history traits.

The onion aphid, Neotoxoptera formosana, poses a significant threat to Allium crops worldwide, causing considerable economic losses and quality degradation. To develop effective pest management strategies, it is crucial to understand the feeding behavior and life history of this pest on different Allium crops. In this study, the electrical penetration graph (EPG) technique was used to monitor the thorn-feeding behavior of the onion aphid on 4 Allium crops: leek, chive, garlic, and shallot. The EPG data revealed distinct feeding patterns, with garlic and shallots being more preferred hosts than chives. Additionally, the aphids primarily fed on the phloem in garlic and shallots. Analysis of life history trait showed that chives provided the most favorable conditions for aphid development and reproduction, while leek exhibited relatively unfavorable conditions. Examination of leaf histology also revealed differences among the crops, which may influence aphid feeding behavior. This study provides valuable insights into the interaction between the onion aphid and different Allium crops, aiding in the development of comprehensive pest control strategies to minimize crop damage and economic losses. The use of advanced techniques like EPG contributes to a more detailed understanding of aphid behavior and shows promise for improving pest management in other plant-pest interactions.

How host plants influence the life history and population growth of Myzus persicae (Hemiptera: Aphididae) and its parasitoid, Aphidius platensis (Hymenoptera: Braconidae)

ABSTRACT The effect of three host plants, sweet pepper, cucumber and eggplant, on the survival and fecundity of Myzus persicae (Sulzer) (Hem.: Aphididae) and population growth parameters of Aphidius platensis as a solitary endoparasitoid of green peach aphid were studied. The raw data were analysed using the age-stage, two-sex life table theory. The results showed that sweet pepper is the most suitable host plant for green peach aphid development and reproduction. The intrinsic rates of increase (r) of M. persicae reared on eggplant, sweet pepper and cucumber were 0.32 ± 0.01, 0.33 ± 0.01 and – 0.071 ± 0.06 d− 1, respectively. Furthermore, other population parameters of aphids raised on sweet pepper and eggplant were significantly higher than corresponding parameter values of aphids fed on cucumber plant. The intrinsic rate of increase (r) of A. platensis reared on sweet pepper was 0.29 ± 0.01 d− 1. The life expectancy (exj ) of A. platensis parasitised pepper raised green peach aphids was 21.08 days on the first day of emergence, and the maximum reproductive value of A. platensis females occurred on the 14th day. Our results showed that sweet pepper could serve as a suitable host plant for rearing M. persicae as a host for A. platensis within a biological control programme context according to the pre-adult period, survival, adult longevity and fecundity of M. persicae. This information could be useful for mass rearing of A. platensis in insectariums where the faster growth and development of aphids are desirable.

Species composition and aphid population seasonal dynamics in vegetable agrocenoses of St. Petersburg and Leningrad region

The purpose of this work was to study the species composition, the dynamics of aphid abundance in vegetable agrocenoses of the Pushkin district of St. Petersburg, as well as Tosnensky and Gatchina districts of the Leningrad region in the conditions of 2021-2022, significantly differing in weather conditions. The catching of insects was carried out using a Malaise trap. In total, during the two-year monitoring period, 40 species of aphids were registrated in the three studied agrocenoses, of which 28 are pests of agricultural crops. The total number of identified species in 2021 was 9 in each of the three research areas; the total number of captured insects was 99. At the end of May – beginning of June, the migration potential of aphids was high, active migration to secondary hosts was observed, however, abnormally high daytime temperatures in June – July with minimal precipitation had a detrimental effect on phytophages. In the weather conditions favorable for the development of aphids during the growing season of 2022, 11 species of aphids were caught in the Pushkinsky district of St. Petersburg, 12 in the Gatchina district, 20 in the Tosnensky district, that is, an increase in the species composition of phytophages was 2.2 times compared to 2021. In 2022, 279 individuals were registered; the largest number of insects was noted in the Tosnensky district – 171. In all the studied agrocenoses, the most numerous of the harmful species was the gray svidin-cereal aphid Anoecia corni F., damaging the roots of perennial grasses (the maximum number of 128 individuals in the Tosnensky district in 2022). A significant number in the same year was observed in the pea Acyrthosiphon pisum Harr., as well as in the cabbage aphid Brevicoryne brassicae L. Quite rare species of aphids for the North-Western region were recorded in the agrocenosis of the Pushkin district: Oxton and maple aphids. The pink tansy aphid was registered only in the Tosno agrocenosis in June 2022. The Malaise trap proved to be convenient to work with, since it is not stationary, can be installed anywhere in any agrocenosis. It can be recommended to use it, first of all, to assess the species diversity of insects, and secondly, to estimate the number.

Effects of the termination of LC30 imidacloprid stress on the multigeneration adaptive strategies of Aphis glycines population.

Aphis glycines Matsumura (Hemiptera: Aphididae) is a major soybean pest that often poses a serious threat to soybean production. Imidacloprid is one of the commonly used insecticides to control the soybean aphid. To investigate the effect of termination of imidacloprid stress on the adaptive strategies of soybean aphid populations, we studied the growth, development, and related metabolism changes when the stress was terminated after 24 generations of imidacloprid stress on A. glycines. The results show that the A. glycines population accelerated its recovery and expanded its population size across generations. The longevity of the adults of the recovering population in the F12, F18, and F24 generations, respectively, was 1.11, 1.15, and 1.11 times longer than the control, while the fecundity was 10.38%, 11.74%, and 11.61% higher than that of the control. The net reproductive rate (R 0) of the recovering population was always significantly higher than that of the control in the F1 to F24 generations. In addition, metabolisms related to the regulation of cell proliferation and oocyte meiosis were significantly upregulated in the recovering population. Even when the imidacloprid pressure disappeared, intergenerational stimuli still affected the adaptive strategies of soybean aphid populations. This effect was manifested as inhibiting the growth and development of the soybean aphid in the early generations and improving the fecundity of the soybean aphid in the later generations. Adaptive soybean aphid populations would surge in the absence of imidacloprid pressure. This study provides an important reference for exploring the adaptability of the A. glycines population under termination of stress from low lethal concentrations of imidacloprid across generations. It also provides important data for monitoring the population dynamics of A. glycines in the field and analyzing the degree of pharmacodynamic stress.

Categories of resistance in cotton genotypes, Gossypium spp. against cotton-melon aphid, Aphis gossypii (Hemiptera: Aphididae).

Cotton-melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is emerging as a potential threat to cotton cultivation worldwide. The resistance categories in Gossypium arboreum to A. gossypii still need to be explored. We screened 87 G. arboreum and 20 Gossypium hirsutum genotypes against aphids under natural field conditions. Twenty-six selected genotypes from these 2 species were tested under glasshouse conditions for resistance categories (antixenosis, antibiosis, and tolerance). Resistance categories were assessed by no-choice antibiosis assay, free-choice aphid settling assay, cumulative aphid days using population buildup tests, chlorophyl loss index, and damage ratings. No-choice antibiosis experiment revealed that the G. arboreum genotypes GAM156, PA785, CNA1008, DSV1202, FDX235, AKA2009-6, DAS1032, DHH05-1, GAM532, and GAM216 had a significant adverse effect on aphid development time, longevity, and fecundity. Gossypium arboreum genotypes CISA111 and AKA2008-7 expressed a low level of antixenosis but possessed antibiosis and tolerance. Aphid resistance persisted uniformly at different plant developmental stages studied. The chlorophyl loss percentage and damage rating scores were lower in G. arboreum than in G. hirsutum genotypes, indicating the existence of tolerance in G. arboreum to aphids. Logical relations analysis of resistance contributing factors depicted the presence of antixenosis, antibiosis, and tolerance in the G. arboreum genotypes PA785, CNA1008, DSV1202, and FDX235, indicating their utility for evaluating the mechanisms of resistance and aphid resistance introgression breeding into G. hirsutum to develop commercially cultivated cotton lines.

LONGTERM FORECAST OF BIOLOGICAL DEVELOPMENT OF PHYTOPHAGES ON BLACK CURRANT

The article presents the results of scientific research on the biological development of the large currant aphid, the red currant head aphid and the gooseberry shoot aphid in the currant agrocenosis. Based on the analysis of the multi-year dynamics of the development of phytophages, a phenological calendar was built, which clearly shows the period of manifestation of the greatest harmfulness of these pests, which is indicated in the third decade of April, while according to the phenological phase of development, this is the VI stage of the biological development of currants. Aphids overwinter in the egg stage at the base of the currant bud. The embryonic development of the egg ends at the beginning of the plant's sap flow. The metamorphosis of this species refers to an incomplete transformation, and therefore parthenogenesis was observed during the experiment. At the 4th stage of organogenesis, we observed the emergence of larvae of the founders, light green in color and spiky sucking mouthparts, which after 2-3 days begin active feeding, which was evidenced by damaged leaves that changed their color over time. The color of leaves damaged by redcurrant aphid has a clear transition from light yellow to red with a halo-shaped bulge. In this species, the salivary enzyme enhances the growth and development of cells, while in the gooseberry shoot aphid, on the contrary, cells die and at the same time cause cell death.
 According to our observations, it has been proven that the development of these phytophages falls on the stage of organogenesis of currant blossoms, and it is strictly forbidden to carry out any plant protection measures during this period. And therefore, we conducted a long-term study of both black currant and sucking phytophages. Such a significant plant-phytophagous combination makes it possible to carry out preventive actions early in the spring on the biological development of sucking phytophages, where in recent years their harmfulness occupies one of the main places, while parthenogenetic females cause significant damage, reducing the yield and quality of berries due to disruption of the normal flow physiological processes of photosynthesis. As a result of nutrition of a parthenogenetic individual, the shoots lag behind in growth, have clearly expressed curvatures of various shapes. It is possible to reduce the colonization of black currant by sucking phytophages by implementing phenological forecasting.

Metabolic relay gene of aphid and primary symbiont as RNAi target loci for aphid control.

Aphids form a stable and mutually beneficial relationship with their primary symbiont Buchnera aphidicola, which play an important role in providing the missing nutrients to the host aphid. Based on the genome sequence of wheat aphid Siotobion miscanthi and its primary symbiont Buchnera that we obtained in our previously study, we identified a metabolic relay gene, ilvA, involved in the isoleucine synthesis pathway between aphids and Buchnera. In this study, we identified the location and sequence structure of ilvA gene in aphid genome, the expression level in different instars and tissues of aphids, and the effect of reducing ilvA expression on the growth and development of aphids by bioinformatics analysis, quantitative PCR, RNAi and bioassay experiments. Our study showed that ilvA was expressed at the highest level in the 2nd instar of the aphid, while the expression of this gene was significantly higher in the aphid bacteriocytes than in other tissues. Notably, this gene is localized on the aphid sex chromosome and remains highly conserved and collinearity across different aphid genomes. Knocking down the expression of ilvA reduced the aphid body weight and production. However, the indices of mortality decreased slightly, but were not significantly different, compared to the control. The results show that the relay genes between aphids and their symbionts in the metabolism of essential nutrients have potential roles in the growth and development of aphids, meanwhile, providing target loci and new ideas for RNAi-based aphid green control strategies.

Host plant-mediated effects on Buchnera symbiont: implications for biological characteristics and nutritional metabolism of pea aphids (Acyrthosiphon pisum).

The pea aphid, Acyrthosiphon pisum, is a typical sap-feeding insect and an important worldwide pest. There is a primary symbiont-Buchnera aphidicola, which can synthesize and provide some essential nutrients for its host. At the same time, the hosts also can actively adjust the density of bacterial symbiosis to cope with the changes in environmental and physiological factors. However, it is still unclear how symbionts mediate the interaction between herbivorous insects' nutrient metabolism and host plants. The current study has studied the effects of different host plants on the biological characteristics, Buchnera titer, and nutritional metabolism of pea aphids. This study investigated the influence of different host plants on biological characteristics, Buchnera titer, and nutritional metabolism of pea aphids. The titer of Buchnera was significantly higher on T. Pretense and M. officinalis, and the relative expression levels were 1.966±0.104 and 1.621±0.167, respectively. The content of soluble sugar (53.46±1.97µg/mg), glycogen (1.12±0.07µg/mg) and total energy (1341.51±39.37µg/mg) of the pea aphid on V. faba were significantly higher and showed high fecundity (143.86±11.31) and weight (10.46±0.77µg/mg). The content of total lipids was higher on P. sativum and T. pretense, which were 2.82±0.03µg/mg and 2.92±0.07µg/mg, respectively. Correlation analysis found that the difference in Buchnera titer was positively correlated with the protein content in M. officinalis and the content of total energy in T. pratense (P < 0.05). This study confirmed that host plants not only affected the biological characteristics and nutritional metabolism of pea aphids but also regulated the symbiotic density, thus interfering with the nutritional function of Buchnera. The results can provide a theoretical basis for further studies on the influence of different host plants on the development of pea aphids and other insects.

UJI PESTISIDA NABATI DAUN CENGKEH (Syzygium aromaticum L.) UNTUK MENGENDALIKAN HAMA KUTU DAUN (Aphid sp.) PADA TANAMAN CABAI RAWIT (Capsicum frutescens L.)

This research aimed to determine the test of clove leaf vegetable pesticide in controlling aphids on the shili pepper. This research was conducted in HulawaVilalge, Telaga Sub-district, Gorontalo Regency, Gorontalo Province, using a Randomized Block Design (RAK) method consisten of 4 levels, namely P0 = control, P1 = 5% clove leaf vegetable pesticide concentration, P2 = 10% clove leaf vegetable pesticide concentration, P3 = 15% clove leaf vegetable pesticide concentration. Each treatment was repeated three times so that 12 experimental units (polybags) were obtained. Data were analyzed using the Analysis of Variance (ANOVA) and Least Significant Difference (BNT) at the 5% leave as an advanced test. The result showed that the clove leaf vegetable pesticide affected aphids in mortality, attack intensity, and population. The concentration of 15% clove leaf vegetable pesticide was the most effective in inhibiting the development of aphids and was able to protect chili pepper from aphids.

Bacteriocyte plasticity in pea aphids facing amino acid stress or starvation during development.

An important contributing factor to the evolutionary success of insects is nutritional association with microbial symbionts, which provide the host insects with nutrients lacking in their unbalanced diets. These symbionts are often compartmentalized in specialized cells of the host, the bacteriocytes. Even though bacteriocytes were first described more than a century ago, few studies have explored their dynamics throughout the insect life cycle and in response to environmental stressors. Here, we use the Buchnera aphidicola/pea aphid symbiotic system to study how bacteriocytes are regulated in response to nutritional stress throughout aphid development. Using artificial diets, we analyzed the effects of depletion or excess of phenylalanine or leucine, two amino acids essential for aphid growth and whose biosynthetic pathways are shared between the host and the symbiont. Bacteriocytes responded dynamically to those treatments, while other tissues showed no obvious morphological change. Amino acid depletion resulted in an increase in bacteriocyte numbers, with the extent of the increase depending on the amino acid, while excess either caused a decrease (for leucine) or an increase (for phenylalanine). Only a limited impact on survival and fecundity was observed, suggesting that the adjustment in bacteriocyte (and symbiont) numbers is sufficient to withstand these nutritional challenges. We also studied the impact of more extreme conditions by exposing aphids to a 24h starvation period at the beginning of nymphal development. This led to a dramatic drop in aphid survival and fecundity and a significant developmental delay. Again, bacteriocytes responded dynamically, with a considerable decrease in number and size, correlated with a decrease in the number of symbionts, which were prematurely degraded by the lysosomal system. This study shows how bacteriocyte dynamics is integrated in the physiology of insects and highlights the high plasticity of these cells.