Aphid Populations Research Articles

Endosymbionts modulate virus effects on aphid-plant interactions

Vector-borne pathogens frequently modify traits of their primary hosts and vectors in ways that influence disease transmission. Such effects can themselves be altered by the presence of other microbial symbionts, yet we currently have limited understanding of these interactions. Here we show that effects of pea enation mosaic virus (PEMV) on interactions between host plants and aphid vectors are modulated by the presence of different aphid endosymbionts. In a series of laboratory assays, we found strong interactive effects of virus infection and endosymbionts on aphid metabolomic profiles, population growth, behavior, and virus transmission during aphid feeding. Furthermore, the strongest effects—and those predicted to favor virus transmission—were most apparent in aphid lines harboring particular endosymbionts. These findings show that virus effects on host-vector interactions can be strongly influenced by other microbial symbionts and suggest a potentially important role for such interactions in disease ecology and evolution.

Different Effects and Application of Methyl Jasmonate on Triticum aestivum L. by aphid Attack

Wheat (Triticum aestivum L.) widely grown in Pakistan during winter season. Aphid is one of the biological factors that inhibits seed germination and plant development. Methyl jasmonate is a plant growth regulator known to take part in defense responses against different types of stresses including Aphid attack. The current study was conducted to improve the growth of the wheat by the foliar application of Methyl jasmonate. Two wheat varieties (Shafaq and Gold) were be sown in plastic pots filled with 6 kg soil in each pot. After germination, wheat plants were treated with different Aphids. After three weeks of treatment data about survival percentage, root attributes, shoot attributes and nutrient analysis was be recorded using standard procedure. The experiment was be conducted under a complete randomized design (CRD) with three replicates and results was be deducted after statistical analysis. Different concentrations of methyl jasmonate (100 micromolar and 1mM) were applied to 20 days old wheat plant. Rhopalosiphum padi was allowed to infest the methyl jasmonate treated plants as well as non-treated plants. Control plants were covered with net and no concentration of methyl jasmonate were applied. Aphids were allowed to infest the plant for 48 hours, after that the plant from all treatments were sampled for all physiological studies. Methyl jasmonate treated plants as well as control plants were used for direct aphid population count after every week. Concluded results depicted that plants exposed to different concentrations of methyl jasmonate affected the root and shoot length, plant height which was further improved through MeJA supplementation.

Genetic Diversity of Barley Accessions from East Asia for Greenbug Resistance.

The greenbug, Schizaphis graminum, is a dangerous pest of barley and other grain crops in the south of Russia. An effective and environmentally friendly way to control this insect is to cultivate resistant varieties. The differential interaction between the phytophage and host plants necessitates the search for new donors of resistance. Seven hundred and seventy-eight accessions of barley from East Asian countries (313 from China, 450 from Japan, and 15 from Nepal) were evaluated for greenbug resistance. The Krasnodar population of the insect and clones isolated from it were used in the experiments. Forty heterogeneous accessions were identified, in which plants with a high level of resistance to the aphid were found. As a result of damage assessment by the 108 S. graminum clones of 11 lines selected from heterogeneous accessions, 52 insect virulence phenotypes were identified. Experiments with aphid test clones showed that all 11 lines possess diverse greenbug resistance alleles, which differ from the previously identified Rsg1, but their efficiency is low. The frequency of clones virulent to ten lines and the cultivar Post (a carrier of the Rsg1 gene) varies from 60.4% to 98.0%. The exception is line 15903, which is resistant to the aphid population and protected by one dominant gene. The high resistance of other lines against a part of the natural population of S. graminum is also under oligogenic control. Lines 15600 and 16190 each have one dominant resistance gene, and line 28129 is protected by two genes, the dominant and recessive ones. A recessive resistance gene is presumably present in line 15600. Lines 16237/1 and 16237/2, isolated from the same collection accession, each have one dominant gene effective against individual aphid clones. The loss of effectiveness of distinctly manifested resistance genes causes the expression of previously masked genes with a weak phenotypic manifestation, which differentially interact with insect genotypes.

Population Dynamics of Mustard Aphid, Lipaphis erysimi (Kaltenbach) on Cauliflower in Relation to Biotic and Abiotic Factors

The field experiment was conducted at Horticulture Farm, S.K.N. College of Agriculture, Jobner during Rabi 2021/22 to know the population dynamics of mustard aphid, Lipaphis erysimi (Kaltenbach). The incidence of aphid started in the first week of December and second week of December remained active throughout the crop season during both years. The population of aphid gradually increased and reached to its peak in the second week of February and first week of February in Rabi, 2021/22, respectively. The correlation studies indicated that the aphid population had non-significant correlation with temperature, relative humidity and sunshine hours in both the years. Both the predators, ladybird beetle and syrphid fly had significant positive relationship with aphid population during both the years.

Synergistic effects of Aphidius colemani (Hymenoptera: Aphidiidae) and Coccinella undecimpunctata (Coleoptera: Coccinellidae) releases for the biological control of Diuraphis noxia in wheat fields

ABSTRACT The Russian wheat aphid, Diuraphis noxia, is a significant pest for grain crops worldwide. Bioagents such as the parasitoid, Aphidius colemani and the predator, Coccinella undecimpunctata have been shown to be effective against many aphid species. This study aimed to investigate the combined effect of releasing these two bioagents on controlling D. noxia without using pesticides. To achieve this, three systems of release were evaluated in the field: (1) the parasitoid A. colemani at rate of 4 mummies/m2, (2) the predator C. undecimpunctata at rate of 10 individuals (3rd larval instar)/m2, and (3) A. colemani (4 mummies/m2) + C. undecimpunctata (10 individuals/m2) and control. After four releases, the combination of A. colemani and C. undecimpunctata resulted in the highest percentage of reduction in aphid population, with a reduction of 95.58, 95.53% in 2020 and 2021, followed by 86.94, 83.92% in A. colemani plots and the lowest reduction percentage in C. undecimpunctata plots, with 65.1, 68.92%, in 2020 and 2021, respectively. Based on these results, it is recommended to use the combination of the two bioagents, A. colemani and C. undecimpunctata for controlling D. noxia in a wheat field. Therefore, the use of a combination of natural enemies, carefully timed and repeated releases, and consideration of intraguild predation dynamics can help to achieve effective biological control of aphids in wheat crops. The use of natural enemies such as A. colemani and C. undecimpunctata can reduce the application of pesticides and promote sustainable pest management practices.

Functional Response and Intraspecific Competition of Three Ladybird Species Feeding on Aphids on Goji Berry Plants in Laboratory and Semi-Field Conditions.

The aphid, Aphis gossypii Glover, is identified as a significant pest that causes severe damage to goji berries in China. To analyze the ladybird consumption of aphids, the functional responses of three ladybird species, Harmonia axyridis, Coccinella septempunctata, and Hippodamia variegata, and intraspecific competition among ladybird individuals were evaluated under laboratory conditions. Moreover, the practical impact of ladybirds on aphid population reduction was investigated in semi-field conditions. We found that all adult ladybirds of the three species exhibited a type II functional response toward aphids. According to Holling's disc equation, H. axyridis exhibited the highest searching efficiency (a = 0.79), while C. septempunctata had the shortest handling time (Th = 5.07 min) among the three ladybird species studied. Additionally, intraspecific competition had a greater impact on H. variegata (m = 0.41) compared to the other two ladybird species. The semi-field study demonstrated that H. axyridis (83.9% reduction) and C. septempunctata (78.7% reduction) exhibited higher efficacy in reducing aphid populations compared to H. variegata (27.3% reduction). This study suggests that H. axyridis and C. septempunctata exhibit potential as effective biological control agents against aphids on goji berry plants and highlights the importance of considering intraspecific competition. However, the results obtained from laboratory and semi-field studies cannot be directly extrapolated to field conditions due to the simplification of these experimental systems. Future field studies are crucial in ensuring the effective implementation of a biological control program.

Effects of Varying Planting Patterns on Wheat Aphids’ Occurrence and the Control Effect of Pesticide Reduction Spraying Process by Unmanned Aerial Vehicle

A walnut–wheat intercropping pattern is practiced widely in southern Xinjiang to alleviate the contradiction between the lack of cultivated land resources and to increase economic value. Previous studies have confirmed that an alley cropping pattern could change the microclimate by supplying additional ecological functions such as windbreak, light interception, water conservation, etc. Cereal aphids (including Sitobion avenae, Rhopalosiphum padi, Metopolophium dirhodum, etc.) are commonly spread pests that harm wheat plants. But, the difference in population numbers between local patterns is still unknown. Pesticide reduction is the national strategy in China to alleviate the contraction between the demand of grain yield and environment protection. Plant protection-unmanned aerial vehicles (UAV) spraying pesticides are the most efficient method to control pests. However, compared to traditional artificial spraying method, how the UAV spraying method affect the control effect of reduced concentration pesticide is unclear. In order to address this problem, we conducted field investigations at Zepu county in southern Xinjiang to test the difference between walnut–wheat intercropping and wheat monocropping patterns for three consecutive years. And, we employed the field experiments to ensure the effectiveness of the reduced concentration common pesticides through the UAV spraying method. In conclusion, we conducted a comparison of the control effects of two spraying methods under conditions of reduced pesticide usage. Our findings revealed that the population of cereal aphids was larger in the intercropping pattern compared to the monocropping pattern. Although the control effect of the reduced treatment was lower than the regular dosage, some treatments still demonstrated sufficient capability to eliminate aphids, particularly when considering the effect within major varieties. Additionally, the use of the UAV spraying method exhibited a satisfactory effect when compared to the traditional artificial spraying method.

Relative Abundance of Insect Pests on French Bean (Phaseolus vulgaris L.) in Relation to Abiotic Factors

The present investigation was carried out during Rabi 2021-22. The incidence of insect pests like aphid, whitefly, Jassid, leaf miner, pod borer was initiated 25 days after sowing till harvesting. The highest incidence of Jassid was observed on French bean crop at 9th SMW (7.20 per cage) and lowest 1st SMW (0.30 per cage), Aphid 8thSMW (45.20 aphids per 10cm terminal shoot) and 52thSMW (2.60 aphids per 10cm terminal shoot). The highest incidence of whitefly observed in 8th SMW (20.70 per cage) and lowest 2nd SMW (0.60 per cage). The highest incidence of Leaf miner was recorded in 11th SMW (40.50% leaf damage) and lowest in 51th SMW (1.50% leaf damage). The highest incidence of pod borer was noticed in 9th SMW (8.70 larvae per plant) and lowest in 1st SMW (0.30 larvae per plant). The Jassid population showed highly significant positive correlation with sunshine and positive significant correlation with maximum temperature and positive correlation with minimum temperature whereas, significant negative correlation with rainfall and negative non-significant correlation with relative humidity. The aphid population showed highly significant positive correlation with sunshine and positive non-significant correlation with minimum and maximum temperature. The whitefly population showed highly significant positive correlation with sunshine and positive non-significant correlation with minimum and maximum temperature. The leaf miner population showed positive highly significant correlation with minimum and maximum temperature and significant positive correlation with relative humidity. The pod borer population showed highly significant correlation with maximum temperature and sunshine. The information generated in the present research can be successfully utilized to formulated effective insect pest management strategies in French bean.

Untangling an insect’s virome from its endogenous viral elements

BackgroundInsects are an important reservoir of viral biodiversity, but the vast majority of viruses associated with insects have not been discovered. Recent studies have employed high-throughput RNA sequencing, which has led to rapid advances in our understanding of insect viral diversity. However, insect genomes frequently contain transcribed endogenous viral elements (EVEs) with significant homology to exogenous viruses, complicating the use of RNAseq for viral discovery.MethodsIn this study, we used a multi-pronged sequencing approach to study the virome of an important agricultural pest and prolific vector of plant pathogens, the potato aphid Macrosiphum euphorbiae. We first used rRNA-depleted RNAseq to characterize the microbes found in individual insects. We then used PCR screening to measure the frequency of two heritable viruses in a local aphid population. Lastly, we generated a quality draft genome assembly for M. euphorbiae using Illumina-corrected Nanopore sequencing to identify transcriptionally active EVEs in the host genome.ResultsWe found reads from two insect-specific viruses (a Flavivirus and an Ambidensovirus) in our RNAseq data, as well as a parasitoid virus (Bracovirus), a plant pathogenic virus (Tombusvirus), and two phages (Acinetobacter and APSE). However, our genome assembly showed that part of the ‘virome’ of this insect can be attributed to EVEs in the host genome.ConclusionOur work shows that EVEs have led to the misidentification of aphid viruses from RNAseq data, and we argue that this is a widespread challenge for the study of viral diversity in insects.

Influence of environmental factors on the population dynamics of <i>Diaeretiella rapae</i> (Hymenoptera: Braconidae) parasitizing <i>Brevicoryne brassicae</i> (Hemiptera: Aphididae) in cauliflower cultivars

The experiment was conducted on five different cauliflower cultivars viz. Early London, PSBK-1, PSBK-25, Pusa Himjyoti and Snowball Super to study the influence of weather factors viz., temperature, relative humidity and rainfall on the population of cabbage aphid, Brevicoryne brassicae (Linnaeus) and its parasitoid, Diaeretiella rapae (MacIntosh) at Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh during the year 2021-2022. The incidence of B. brassicae was first recorded on cv. Early London, Pusa Himjyoti and Snowball Super during 52nd Standard Meteorological Week (SMW) followed by PSBK-1 and PSBK-25 during 1st SMW while the parasitoid was first noticed in 8th SMW on cv. Early London followed by PSBK-1 (9th SMW), Snowball Super (10th SMW), PSBK- 25 and Pusa Himjyoti (11th SMW). The aphid population was maximum (177 aphids/plant) during 10th SMW whereas, the population of parasitoids was maximum (4.90 mummified aphids/plant) during 11th SMW on Early London. Among all the cultivars, the per cent parasitism by D. rapae was highest (17.31%) on Pusa Himjyoti during 13th SMW. The populations of cabbage aphid and its parasitoids exhibited positive correlation with the temperature and negative correlation with relative humidity and rainfall.

Seasonal abundance and mutual interference of <i>Diaeretiella rapae</i> (McIntosh) on <i>Brevicoryne brassicae</i>

Brevicoryne brassicae (Hemiptera: Aphididae), known as cabbage aphid, is cosmopolitan in distribution that infests cruciferous crops such as broccoli, cabbage, cauliflower, and mustard. Brevicoryne brassicae is suppressed by various species of natural enemies, the most important and abundant being Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae). The present study was carried out at Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni Solan, Himachal Pradesh, on the seasonal abundance and mutual interference of the parasitoid, D. rapae during the years 2020-2021. The study showed the peak population of both host (221.36 aphids/plant) and parasitoid (27.28 mummified aphids/plant) with 12.32 per cent parasitization on the 10th Standard Meteorological Week (SMW). On the 14th SMW of 2021, the aphid population was lowest (2.72 aphids/plant) and parasitization by D. rapae was highest (47.05%). The D. rapae when foraged at densities of 2, 4, 6 and 8 parasitoids per 30 and 50 constant host nymphs, the third-instar host nymphs had a higher mutual interference coefficient than fourth instar host nymphs. Therefore, D. rapae can be utilized as an important biocontrol agent in the management programme of a cabbage aphid (B. brassicae).

Population Dynamics of the Coriander Aphids in Hyper Arid Region of Rajasthan and their Correlation with Biotic and Abiotic Factors

Population dynamics of coriander aphid and their correlation with biotic and abiotic factors were studied at instructional farm of the department of Entomology, College of Agriculture, SKRAU Bikaner during Rabi, 2020-21 and 2021-22. The incidence of coriander aphid, H. coriandri (Das) commenced in the fourth week of January (4th SMW) and remained active throughout the crop season i.e. upto third week of March during both the years (2020-21 and 2021-22). The population of H. coriandri increased gradually and attained its peak in last week of February/first week of March (9th SMW) during both the years. After peak aphid population started declining and reached to low levels in the 11th SMW near maturity of the crop during both the years. Simultaneously the occurrence of predator, Coccinella septempunctata coincided with the population of aphids during both the years. Maximum and minimum temperatures had positive correlation with aphid population during both the years i.e. 2020-21, 2021-22. Morning and evening relative humidity showed negative correlation with aphid population. whereas, population of C. septempunctata was significant positively correlated with aphid population during both years.

Evaluation of insecticides against mustard aphid, Lipaphis erysimi (Kaltenbach)

Field experiments were conducted to evaluate the efficacy of various insecticides against mustard aphid, Lipaphis erysimi on mustard crop during rabi seasons 2020-21 and 2021-22. The results on the field efficacy revealed that performance-wise treatments were in the order of imidacloprid 17.8 SL > thiamethoxam 25%WG> acetamiprid 20%SP > dimethoate 30%EC > malathion 50%EC > fipronil 5%EC > profenofos 50%EC > buprofezin 25%EC. The least population (5.40/plant) of aphid was obtained with application of imidacloprid 17.8% SL at 7 DAS and (6.67/plant) at 10 DAS during 2020-21 and 2021-22, respectively. The same trend was observed till 28th day in comparison to rest of the treatments and untreated control. Significant reduction in population was observed with imidacloprid 17.8 SL @ 27.0 gm a.i./ha followed by thiamethoxam 25%WG @ 25 gm a.i./ha and dimethoate 30%EC @ 200 gm a.i./ha. Imidacloprid and thiamethoxam were significantly superior to other treatments. The maximum yield was obtained with imidacloprid (17.99 and 18.22 q/ha) followed by thiamethoxam (16.62 and 17.37q/ha) during 2020-21 and 2021-22, respectively.

Efficacy assessment of garlic extract as a natural aphid control agent on infected tomato plants

This controlled pot experiment aimed to assess the effectiveness of garlic extract as a natural aphid control agent on infected tomato plants (Solanum lycopersicum). The study investigated the impact of different doses of garlic extract on plant height, leaf damage, fruit production, and overall yield. The garlic extract was prepared by diluting crushed garlic bulbs with water to achieve the desired concentrations. The experiment employed a randomized complete block design with four treatment groups: a control group (0%), low dose (10%), medium dose (30%), and high dose (50%) of garlic extract. The treatments were applied using a handheld sprayer, and the plants were monitored for aphid populations using visual inspection and sticky traps. Data collected were subjected to statistical analysis, including analysis of variance (ANOVA), to determine significant differences between treatments. The results revealed that higher doses of garlic extract led to increased plant height, decrease in leaf damage caused by aphids, higher fruit production, and improved overall yield. The control group exhibited the lowest values for all parameters, while treatments with garlic extract showed significant improvements. The highest yields were observed in Treatment 50%, where plants treated with the highest dose of garlic extract yielded 41.2 kg per treatment. These findings demonstrate the potential of garlic extract as an effective aphid control agent, capable of enhancing tomato crop yield and economic returns for farmers.

Bio-Chemical Factors Associated with Resistance to Aphid, Hyadaphis coriandari (Das) in Fennel at Bikaner, Rajasthan, India

Fennel (Foeniculum vulgare Miller) is a significant spice crop from the Apiaceae family, often referred to as 'saunf,'. Aphid, Hyadaphis coriandari (Das) remained chief constraints in realising potential production and productivity of fennel in arid region. The biochemical characters viz., free amino acids, total soluble sugar and phenol content in different genotypes of fennel were responsible for resistance. The experiment was conducted using a randomized block design and involved ten different fennel varieties with three replications. The plot size was 2.4 x 3.0 meter and inter row and inter plant distance were 40 cm x 20 cm, respectively. The biochemical characters of varieties/entries viz., total soluble sugar, total phenols and free amino acids were estimated during peak aphid population on the crop. The free amino acids content in different varieties varied from 1.05 to 2.93 per cent. The variety RF-205 contained lowest per cent of free amino acid, harbored minimum aphid population and the RF-145 contained highest per cent of free amino acids and had highest aphid population. The RF-205 variety lowest content of TSS (0.90 mg/100g) harbored lowest aphid population (44.40 aphids/plant) and variety AF-2 contained highest 1.14 mg/100g of TSS. That shows least susceptibility against this pest. The total phenol content ranged from 2.33 to 4.55 per cent being minimum in RF-145 and maximum in variety RF-205. Total phenol (r= -0.99) were significantly negatively correlated with peak aphid population.

Aphid species populations and their seasonal fluctuation in Prunus orchards affected by Sharka disease within the quarantine areas of Argentina

Sharka is a disease of stone fruits, produced by the Plum Pox Virus and transmitted by aphids. It was detected for the first time in Argentina in 2004. In order to assess the aphid species that could act as a potential vector of this disease, we described the aphids community and seasonal fluctuation within two Prunus orchards affected by Sharka disease, located within two quarantine areas in Cuyo Region. Aphids were trapped weekly from October (spring) to April (autumn) during 2011-2012 and 2012-2013, by using yellow water traps (TAA), and identified using winged aphid’s taxonomic keys. In total, 27 aphid species were identified. The most dominant species collected was Myzus persicae (Sulzer). Orchard-trapped population of this dominant aphid showed seasonal fluctuation with two peaks, November (spring) and March (autumn).

Population dynamics of arthropods on tomato (Lycopersicum esculentum l.) in Vindhya plateau region of Madhya Pradesh

The field experiment results on “population dynamics of different insect pest and their natural enemies on tomato” showed that the aphid population peaked in the 7th SMW (8.83 aphids/6 leaves) during Rabi Season 2021-22. Amrasca biguttula population attained its peak (6.33 jassids/ 6 leaves) during the 11th SMW. The first peak of the leaf miner population was observed (4.67 leaf miner/6 leaves) during the 11th SMW and the second during the 16th SMW. The tomato mirid bug had the highest mean population (5.80 bugs/ plant) during the 11th SMW. The damaged fruit borer (H. armigera) was first recorded during the 9th SMW and maximum fruit damage was 96 per cent during the 13th SMW. The maximum mean population of ladybird beetle (5.26 lady beetles/ plant) and weaver ant (12.06 Weaver ant/ plant) was recorded during the 11th standard week. The peak population of damselfly (2.20 damselfly/ plant), whitefly (7.83 whitefly/6 leaves) and dragonfly (2.20 dragonflies/plant) were observed during the 10th SMW.

Jasmonic acid impact on botanical and morpho-physiological characteristics of wheat (Triticum aestivum L.) infected by Aphid

Wheat (Triticum aestivum L.) is the most essential cereal crop among all other crops of Pakistan and belongs to the family poaceae. The experiment was performed to evaluate the response of exogenously applied jasmonic acid on wheat (Triticum aestivum L.) growth parameter against aphid attack. Two wheat varieties i.e., Fareed-2006 and Paktoon-2016 are cultivated in pots and different concentrations of Jasmonic acid (100 µM and 1 mM) were applied. Concluded results showed that aphid infested plants decreased root and shoot length, plant height, total soluble protein and chlorophyll contents but increased the POD and SOD contents, MDA contents, catalase, H2O2 concentrations and phenolics of wheat (Triticum aestivum) which was further improved through jasmonic acid application. Jasmonic acid treated plants showed better results than control and aphid infested plants. Jasmonic acid spray helped plants to recovery from aphid stress by increasing antioxidant enzyme synthesis, POD (Peroxidase), SOD (Superoxide dismutase) and CAT (Catalase). The results showed that JA sprayed plants have a reduced aphid population than controls plants. When compared to jasmonic acid (100 µM), the greater concentration of jasmonic acid (1mM) showed more effective. Use of jasmonic acid against devastating diseases seems to hold a more promising future in the pest management and agriculture sector.

Double-stranded RNA mediated knockdown of sucrase gene induced mortality and reduced offspring production in Aphis gossypii.

The importance of gut sucrase in maintaining osmotic equilibrium and utilizing phloem contents as a carbon source has been widely investigated and proven in sap-sucking insects. In the present study, silencing of Aphis gossypii sucrase1 (Agsuc1) was carried out by double-stranded RNA (dsRNA), which would be lethal to it due to disruption of osmotic balance. The dsRNA corresponding to Agsuc1 was synthesized by two methods, i.e., in vitro synthesis using T7/SP6 RNA polymerase and in vivo synthesis by bacterial expression, i.e., Escherichia coli strain HT115 transformed with the L4440 vector system. Oral delivery of double-stranded Agsuc1 synthesized in vitro (dsAgsuc1) and in vivo (HT115Agsuc1) induced around 50% mortality in nymphs of A. gossypii. Moreover, the number of offspring produced by the survived aphids decreased by 39-43%. Parthenogenetic reproduction of the aphids is the critical factor for their fast population build-up, leading to yield losses of economic significance. Thus, the present study demonstrated that the silencing of the Agsuc1 gene reduced the aphid population by killing it and inhibited the population buildup by reducing the number of offspring produced by the survived aphids, likely to result in a significant reduction in crop damage. The production of dsRNA by bacterial expression is a cost-effective method. It has the potential to be used as a biopesticide. The sucrase gene is an excellent putative target gene for RNAi against A. gossypii. It could be used to develop a transgenic plant that produces dsAgsuc1 to keep A. gossypii populations below the economic threshold level.

Fine-Scale analysis of both wild and cultivated horned galls provides insight into their quality differentiation

BackgroundGalla chinensis is a traditional Chinese medicine (TCM) produced due to the interaction between the Fordinae aphids and the Rhus plant species. Horned galls with high tannin content are the most widely cultivated gall type, and Wufeng county of Hubei province in China is the center of cultivation. However, long-term artificial cultivation and domestication of horned galls to meet the increasing production demand have led to quality degradation. Understanding the reasons underlying quality degradation is urgent for horned gall production and application. The present study used a combination of metabolic, genetic, and ecological analyses to investigate the quality and genetic differentiation of the horned galls under long-term domestication as well as the potential relationships between them.ResultsAnalysis of gallic acid content and other three phenotypic traits (fresh weight, gall size, and wall thickness) revealed quality differentiation of horned galls collected from five locations in Wufeng, in which the cultivated samples from Wang Jiaping (WJP) showed the highest degradation. Genetic differentiation between the cultivated and wild Rhus chinensis trees in WJP, and between WJP and the other populations was detected based on SSR molecular markers, however, no significant difference in genetic structure was seen for the aphid populations. Among the various ecological factors examined, temperature was identified as the primary one affecting the quality of horned galls.ConclusionsBoth genetic and ecological factors caused quality differentiation of horned galls. The collection of diverse germplasm of host trees and aphids will help reduce the quality degradation of horned galls in Wufeng.