Oriental Fruit Moth Research Articles

Identification and Occurrence of the Dominant Parasitic Wasp Therophilus festivus of Larval Grapholita molesta

The oriental fruit moth, Grapholita molesta, is one of the most destructive orchard pests worldwide. Due to its behavior of boring into twigs and fruits, controlling the pest at the larval stage using insecticides is challenging. We studied the enemy species at the larval stage of G. molesta from seven fruit-growing areas by sampling peach shoots and fruits bored by its larvae. The occurrence and biological characteristics of the dominant enemy were verified using field investigation and laboratory experiments. The results showed that the dominant enemy species of larval G. molesta was identified as Therophilus festivus. The larval, cocoon, and pupal stages of T. festivus could not survive at 35 °C. The developmental durations of these three stages at 20 °C were significantly longer than those at 25 °C and 28 °C. Consecutive years of investigation in Xinxiang, China, indicated that T. festivus can parasitize G. molesta larvae collected at each generation. The parasitism rates in June (45.16%), July (63.50%), and August (48.37%) were significantly higher than those in April (15.27%). Most field research in China has focused on the release of parasitoids to control G. molesta eggs. Our study establishes a foundation for the control of G. molesta larvae using T. festivus.

Host–Pest Interactions: Investigating Grapholita molesta (Busck) Larval Development and Survival in Apple Cultivars under Laboratory and Field Conditions

Phenology models are widely used in Decision Support Systems to predict the phenology of pests. Grapholita molesta (Busck) (Lepidoptera: Tortricidae), a polyphagous pest, has a high prevalence in apple trees (Malus domestica Borkh.) (Rosales: Rosaceae) in certain areas, despite the fact that apple trees are considered secondary hosts. Its natural behavior of feeding inside plant tissue at the larval stage makes monitoring and planning methods of control critical for Integrated Pest Management. The development times and survival rates of two field populations of G. molesta larvae on apple cultivars ‘Gala’, ‘Golden’, and ‘Fuji’ were determined under different temperature (constant versus field fluctuation) and feeding conditions (diet versus apples attached to the tree and detached from the tree). The results showed that G. molesta fitness in apples is affected by fluctuating temperature regimes in the field, the condition of the fruit, whether or not the fruit is attached to the tree, and the cultivar. The temperature was the main cause of the differences in the studied parameters. Larvae development time was delayed due to fluctuating field temperatures. Larvae had a shorter development time in fruits detached from the tree compared to attached fruits, and apple cultivars influenced development time in both laboratory and field conditions, with the ‘Golden’ cultivar having better fitness and a higher rate of larvae survival in the fruits attached to the tree. These factors need to be considered to properly adjust the phenology models and improve the Integrated Pest Management system of apples.

The Oriental Fruit Moth (Grapholitha Molesta Busck.) and its Natural Enemies in the Absheron Peninsula

Abstract Garden plants, trees and bushes suffer damages caused by lots of pests by 30-50 % every year, and sometimes by 80-90 % during the period when they grow massively. For this purpose, scientific bases for the use of perspective entomophages in the biological fight against harsh pests by studying the species composition, bioecological features of 6 species of insects, which damage garden and forest plants, and entomophages (parasites and predators), which regulate their number, have been developed in Azerbaijan. The research paper established that the oriental fruit moth infests fruit crops by 50-60 %. It was found that 22 types of parasites play a role in the regulation of abundance. Among them, macrocentrus infests oriental fruit moth larva up to 80 %, scambus up to 60 %, apanteles up to 40-50 %. The scoliidae parasite is of economic importance and can be used for biological control against the oriental fruit moth. Considering the prospects of some parasites, the bioecological features on the Absheron Peninsula have been studied.

Myosuppressin signaling deficiency affects ovarian development via repression of 20-hydroxyecdysone biosynthesis in Grapholita molesta

The steroid 20-hydroxyecdysone (20E) is crucial in regulating ovarian development. However, the neuropeptidergic mechanisms underlying ovarian development via 20E are underexplored. In this study, we investigated myosuppressin (MS) signaling in the dominant fruit pest Grapholita molesta and revealed that MS signaling is necessary for 20E biosynthesis during ovarian maturation. Pharmacological and molecular docking analyses confirmed that the GmMS mature peptide could activate its receptor GmMSR. Additionally, transcript expression analyses of GmMS and GmMSR showed different distribution patterns in adults. Notably, GmMSR was also detected in the ovaries of sexually mature females. RNAi-mediated dysfunction of GmMS or GmMSR specifically decreased fertility in females. Furthermore, GmMS or GmMSR knockdown decreased vitellogenin synthesis and uptake, thereby delaying ovarian development. RNA-seq, gene expression validation, and hormone quantification further revealed that GmMS signaling depletion blocked 20E biosynthesis in the ovary. Finally, exogenous MS rescued most dsGmMS- or dsGmMSR-induced ovarian defects and 20E titers. These results suggest that MS/MSR-to-20E signaling regulates ovarian development through vitellogenesis, providing a new perspective on the development of neuroendocrine targets that suppress pest field populations.

Nanoparticle-mediated calmodulin dsRNA and cyantraniliprole co-delivery system: High-efficient control of two key pear pests while ensuring safety for natural enemy insects

Currently, the predominant method for managing pests in orchards is chemical control. However, prolonged use of chemicals leads to resistance issues and raise ecological safety. A promising approach to tackle these challenges involves nanoparticles-mediated delivery system of dsRNA and pesticides. Despite its potential, this strategy has not been widely applied in controlling pests in pear orchards. In this study, we developed a nanoparticle-mediated ternary biopesticide to tackle resistance and safety concerns associated with calmodulin dsRNA and cyantraniliprole. Initially, we assessed the effectiveness of cyantraniliprole against two key pear pests, Grapholita molesta and Cacopsylla chinensis. Subsequently, we observed an upregualtion of genes CaM and CN following cyantraniliprole treatment. Furthermore, inhibiting or silencing GmCaM and CcGaM enhanced the sensitivity to cyantraniliprole more effectively. By introducing hairpin RNA into the pET30a-BL21 RNaseIII− system to silence GmCaM and CcCaM, we developed a nanoparticle-mediated co-delivery system that exhibited improved control over these two pests. Importantly, our research demonstrated that using reduced cyantraniliprole dosages through ternary biopesticides could help mitigate risks to natural enemies. Overall, our research emphasizes the enhanced effectiveness of ternary biopesticides in boosting the performance of dsRNA and pesticide against pear pests, while fostering environmental sustainability—a novel advancement in this field.

The cultivable gut bacteria Enterococcus mundtii promotes early-instar larval growth of Conogethes punctiferalis via enhancing digestive enzyme activity.

Gut bacteria are crucial in influencing insect development and even phenotypic plasticity. The yellow peach moth Conogethes punctiferalis, as a significant borer pest, has been the subject of limited reports regarding the structural and diversification changes in its gut microbiota during feeding, and their potential impacts on the growth and development of the host insects. This study, employing 16S rRNA sequencing, demonstrates distinct shifts in the larvae gut microbiome of C. punctiferalis between different feeding stages, highlighting a pronounced diversity in the early-instar with Enterococcus as a predominant genus in laboratory populations. Through in vitro cultivation and sequencing, three bacterial strains - Micrococcus sp., Brevibacterium sp. and Enterococcus mundtii - were isolated and characterized. Bioassays revealed that E. mundtii-infused corn significantly boosts early-instar larval growth, enhancing both body length and weight. Quantitative PCR and spectrophotometry confirmed a higher abundance of E. mundtii in younger larvae, correlating with increased digestive enzyme activity and total protein levels. This study reveals the heightened gut microbiota diversity in early instars of C. punctiferalis larvae, highlighting that Enterococcus represent a predominant bacteria in laboratory populations. In vitro cultivation and bioassays unequivocally demonstrate the significant role of the cultivable gut bacteria E. mundtii in promoting the growth of early-instar larva. These findings provide a solid theoretical foundation for advancing the comprehension of the intricate interactions between gut microbiota and insect hosts, as well as for the development of eco-friendly pest control technologies based on targeted manipulation of insect gut microbial communities. © 2024 Society of Chemical Industry.

Bio-ecology and management approaches of yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae)

Bio-ecology and management approaches of yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae)

Trypsin-encoding gene function of efficient star polycation nanomaterial-mediated dsRNA feeding delivery system of Grapholita molesta.

Grapholita molesta is an important and harmful fruit pest worldwide, with widespread feeding hosts. Trypsin, an indispensable hydrolytic digestive protease in the insect gut, is crucial in digestion, growth and development. We analyzed the characteristics of the trypsin-encoding genes, screened for the optimal dose of RNAi mediated by nanocarriers, and investigated various indices of larval growth and development of G. molesta. Gut content (GC) and RNase A degraded double-stranded RNA (dsRNA), with a faster degradation rate at higher concentrations. Star polycation (SPc) nanomaterials protected dsGFP from degradation by anion-cation binding and did not migrate through agarose gel. The key conserved motifs of the trypsin-encoding genes were similar, exhibiting high homology with those in other lepidopteran insects. An interference efficiency of ≈70% was achieved with SPc nanomaterial-mediated RNA interference with 0.05 μg dsRNA. The efficiency of continuous interference was stable. Trypsin activity, body weight of 8-day-old larvae, pupal weight and emergence rate were significantly reduced, and the larval stage was significantly prolonged. The investigated trypsin gene is a key target gene in the growth and development of G. molesta. We investigated the efficiency and convenience of feeding SPc nanomaterials in a functional study of insects. Our results provide valuable data for the development of efficient trypsin-targeting pesticides. © 2024 Society of Chemical Industry.

Selectivity and efficiency: evaluation of synthetic Grapholita molesta sexual pheromones

Selectivity and efficiency: evaluation of synthetic Grapholita molesta sexual pheromones

Heterologous expression and characterization of two delta glutathione S-transferases genes involved in imidacloprid metabolism in Grapholita molesta

Glutathione S-transferases (GSTs) are multifunctional enzymes, and insect GSTs play a pivotal role in the metabolism of insecticides. Grapholita molesta is a worldwide pest that causes substantial economic losses to the fruit industry. However, it remains unclear how imidacloprid, a commonly used insecticide in orchards, is metabolized by G. molesta. In the present study, the synergist diethyl maleate (DEM), which inhibits the GST activity, exhibited a 22-fold synergistic ratio against imidacloprid. Two new GST genes, GmGSTD2 (OR096251) and GmGSTD3 (OR096252), were identified and successfully cloned, showing the highest expression in the Malpighian tubes. Knockdown of GmGSTD2 and GmGSTD3 by RNA interference, increased the mortality of G. molesta from 28% to 47% following imidacloprid treatment. Both recombinant GmGSTD2 and GmGSTD3 proteins exhibited 1-chloro-2,4-dinitrobenzene (CDNB) activity and could be inhibited by imidacloprid in vitro, with maximum inhibition was 60% for GmGSTD2 and 80% for GmGSTD3. These results suggested that GSTs participate in the metabolism of imidacloprid with GmGSTD2 and GmGSTD3 playing key roles in this process.

How Climate Warming Influences the Phenology of Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) in China: Insight from Long-Term Historical Data.

Grapholita molesta (Busck, 1916), a significant pest affecting various fruits such as pears, apples, peaches, etc., is highly adaptable to changing temperatures. However, the phenological response mechanism of this pest to climate warming remains unclear. To address this issue, we collected population dynamics data of G. molesta in China over the years along with corresponding climate data. We analyzed five phenological indexes: the first, end, and peak occurrence dates of contemporary adults as well as the first and peak occurrence dates of overwintering adults in China. Results revealed an upward trend in the annual average temperature and average temperature of the four seasons in regions infested by G. molesta in eastern, northeastern, northwestern, northern, and southwestern China from 1980 to 2020. Notably, the population peak date of overwintering adults in northeastern and eastern China significantly advanced along with the first occurrence date and the population peak date of overwintering adults in northern China. Additionally, the population peak date of contemporary adults in northwestern China significantly advanced. However, the end occurrence date of contemporary adults in northern China was significantly delayed, as was the first occurrence date of overwintering adults in northwestern China. Furthermore, our study demonstrated spatial heterogeneity in the phenological response of G. molesta to climate warming across China. This study elucidates the phenological response of G. molesta to climate warming, offering valuable insights for predicting future pest infestations and informing adaptive pest management strategies in fruit tree cultivation.

Comparison of gut transcriptome and bacterial composition of the yellow peach moth, Conogethes punctiferalis larvae associated with host plants adaptation

The yellow peach moth, Conogethes punctiferalis, is one of the most destructive polyphagous pests to corn crops in the Huang-Huai-Hai summer corn region of China. However, little is known about the host plant adaptation mechanism of C. punctiferalis. In this study, we analyzed the performance of C. punctiferalis on two of its favorable host plants (corn and sorghum). Then, we used RNA-seq and 16S rRNA sequencing to explore the potential adaptation mechanism of C. punctiferalis on these two host plants. Results showed that C. punctiferalis gained more fresh weight on sorghum while its total lipid and triglyceride content was significantly lower than on corn. In total, 2155 genes weredifferentially expressed (DEGs) between corn and sorghum reared C. punctiferalis. Most of the DEGs were involved in nutritional biosynthesis and metabolism including amino acid biosynthesis, protein digestion and absorption, and glycolysis. Enzymatic analyses revealed that C. punctiferalis reared on corn had higher trypsin activity but lower P450 activity than that reared on sorghum. Meanwhile, C. punctiferalis reared on corn harbored more gut bacteria, while its diversity is lower than that reared on sorghum. The potential functional prediction of the gut bacteria revealed that nutritional metabolism functions were differently enriched between two host plants of C. punctiferalis. Taken together, these findings clarify the impact of host plants on the gene expression and gut bacteria in C. punctiferalis. They also suggest that the plasticity of gene expression and gut bacteria cooperatively contribute to insect host adaptation of insects.

Using a rainfall simulator thrust type to evaluate the efficacy of insecticides in a apple orchard

A rainfall simulator thrust type was evaluated as a novel tool for studying the efficacy of insecticides against pests in apple orchards, compared to traditional laboratory methods. The simulator was installed and calibrated to simulate rainfalls of 50 mm h-1 on a 7-year-old apple orchard. The results of Grapholita molesta (Lepidoptera: Tortricidae) control in the field differed from those obtained in laboratory. The control efficacy in the orchard was lower than that obtained in laboratory tests. Control percentages varied throughout the simulated rains, with increases at the beginning of rainfall followed by decreases. The use of the push-type rainfall simulator provides advantages to research experiments, as it allows for evaluations under field conditions at different developmental stages of plants in orchards under different management practices, with results closer to field reality than those currently generated by laboratory tests.

Penicillium-Infected Apples Benefit Larval Development of Conogethes punctiferalis via Alterations of Their Gut Bacteria Community and Gene Expression.

Pathogenic microorganisms can impact the behavior and physiology of herbivores by direct or indirect means. This study demonstrated that yellow peach moth Conogethes punctiferalis larvae feeding on Penicillium-infected apples exhibited significantly longer body length and weight parameters compared to the control group. The sequencing of gut 16S rRNA showed a significant increase in the diversity and abundance of bacteria in the larvae feeding on Penicillium-infected apples. Additionally, transcriptomic sequencing of the larval gut indicated significant upregulation of genes related to digestion and cuticle formation after consuming Penicillium-infected apples. Furthermore, enzyme activity assays revealed notable changes in the trypsin and lipase activity. Consequently, these alterations in gut microbiota structure, diversity, and gene expression levels may underlie the observed growth and developmental variations in C. punctiferalis larvae mediated by pathogenic microorganisms. This study holds theoretical significance for a deeper understanding of the tripartite interaction among microorganisms, insects, and plants as well as for the development of novel pest control measures based on gut microbiota.

Molecular characterization and functional analysis of the ecdysone receptor isoform (EcR) from the oriental fruit moth Grapholita molesta (Lepidoptera: Tortricidae).

20-Hydroxyecdysone (20E) plays a vital role in a series of biological processes, via the nuclear receptors, EcR/USP by activating the ecdysone regulatory cascade. To clarify the role of EcR during the development of Grapholita molesta, the complementary DNA of ecdysone receptor isoform B1 (GmEcR-B1) was obtained from the transcriptome of G. molesta and verified by PCR. Alignment analysis revealed that the deduced protein sequence of GmEcR-B1 was highly homologous to EcR proteins identified in other lepidopteran species, especially the EcR-B1 isoform in Spodoptera litura. Quantitative real-time PCR showed that GmEcRs was expressed at all test developmental stages, and the expression level of GmEcRs was relatively higher during the period of the 3rd day of fifth instar larvae to 2nd of pupa than those in other stages. Moreover, the messenger RNA of GmEcRs was much more strongly expressed in the Malpighian tubule and epidermis than those in other tissues, which suggests that this gene may function in a tissue-specific manner during larval development. Silencing of GmEcRs could significantly downregulate the transcriptional level of ecdysone-inducible genes and result in increased mortality during metamorphosis and prolonged prepupal duration. Taken together, the present results indicate that GmEcRs may directly or indirectly affect the development of G. molesta.

Evaluation of Lipid Quality in Fruit: Utilizing Lipidomic Approaches for Assessing the Impact of Biotic Stress on Pecans (Carya illinoinensis).

There is a scarcity of data on how the lipid composition of oily seeds changes in response to biotic stress. Yellow peach moth (Conogethes punctiferalis) has caused massive economic losses on the pecan (Carya illinoinensis) industry. Lipidomics is used in this study to determine the lipid composition of pecan and how it changes in response to insect attack. Pecan had 167 lipids, including 34 glycerolipids (GL), 62 glycerophospholipids (GP), 17 fatty acyls (FA), 41 sphingolipids (SP), and 13 saccharolipids (SL). The effects of biotic stress on lipids, particularly GL and GP, were significant. Biotic stress significantly reduced the lipid content of chains longer than 48. Forty-four significantly different lipids were discovered as potential biomarkers for distinguishing non-infected pecans from infested pecans. In addition, we used bioinformatics to identify the five most important metabolic pathways in order to investigate the processes underlying the changes. Our discoveries may offer valuable insights for enhancing pecan production in the future and contribute novel perspectives towards enhancing the nutritional value of pecans.

Secondary metabolites in host pears defense against two fruit borers and cytochrome-P450-mediated counter-defense

Herbivorous insects have evolved metabolic strategies to survive the challenges posed by plant secondary metabolites (SMs). This study reports an exploration of SMs present in pears, which serve as a defense against invasive Cydia pomonella and native Grapholita molesta and their counter-defense response. The feeding preferences of fruit borers are influenced by the softening of two pear varieties as they ripen. The content of SMs, such as quercetin and rutin, increases due to feeding by fruit borers. Notably, quercetin levels only increase after C.pomonella feeding. The consumption of SMs affects the growth of fruit borer population differently, potentially due to the activation of P450 genes by SMs. These two fruit borers are equipped with specific P450 enzymes that specialize in metabolizing quercetin and rutin, enabling them to adapt to these SMs in their host fruits. These findings provide valuable insights into the coevolution of plants and herbivorous insects.

Dissipation kinetics, residue level, and risk assessment of chlorantraniliprole in Rosa roxburghii and its residue removal using household decontamination technique

Rosa roxburghii (R. roxburghii) is edible and medicinal fruit rich in vitamin C. Residues and potentially ecological risks of chlorantraniliprole (CAP) in the R. roxburghii orchard have aroused concern considering its extensive use for controlling oriental fruit moth, aphid, and whitefly of R. roxburghii. In this study, an effective UPLC–MS/MS method was developed for quantitation of CAP in R. roxburghii and soil using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) dispersive solid-phase extraction with average recoveries of 73.89–96.63% and a relative standard deviation of <15%. Dissipation dynamics and terminal residue trials under the field conditions in 2021 and 2022 showed that half-lives of CAP in R. roxburghii (2.64–2.70 days) were shorter than those in soil (3.58–3.80 days), and its terminal residues in R. roxburghii and soil were 0.034–0.818 mg kg-1 and 0.003–0.015 mg kg-1, respectively. Long-term dietary and soil ecological risk assessments indicated that the risk quotient was significantly less than 100%, meaning that the use of CAP on R. roxburghii at the recommended dosage was safe to consumers and soil ecology system, and that maximum residue limits (MRLs) and safe pre-harvest intervals of CAP in R. roxburghii were recommended as 0.7 mg kg-1 and 14 days, respectively. Removal experiments of CAP residues from R. roxburghii using simple household processing approaches exhibit that 2% baking soda water had the highest removal efficiency (56.04–60.33%). This study provides the basic data for establishing MRL, the safe and rational use of CAP in R. roxburghii production as well as the household decontamination prior to consumption of R. roxburghii fruits.

Fine structure of the compound eyes of the crepuscular moth Grapholita molesta (Busck 1916) (Lepidoptera: Tortricidae).

Morphological organization, ultrastructure and adaptational changes under different light intensities (10000, 100, 1, and 0.01mW/m2) of the compound eye of the oriental fruit moth Grapholita molesta (Busck 1916) were investigated. Its superposition type of eyes consist of approximately 1072 ommatidia in males and 1029 ommatidia in females with ommatidial diameters of around 15μm. Each ommatidium features a laminated corneal lens densely covered by corneal nipples of 256nm in height. Crystalline cones are formed by four cone cells, proximally tapering to form a narrow crystalline tract with a diameter of 1.5μm. Eight retinula cells, two primary and six secondary pigment cells per ommatidium are present. The 62.3μm long rhabdom is divided into a thin 1.8μm wide distal and a 5.2μm wide proximal region. Distally the fused rhabdom consists of the rhabdomeres of seven retinula cells (R1-R7) and connects with the crystalline cone. In the proximal rhabdom region, the pigment-containing retinula cell R8 occupies a position in centre of the rhabdom while R1-R7 cells have taken peripheral positions. At this level each ommatidial group of retinula cells is surrounded by a tracheal tapetum. In response to changes from bright-light to dim-light adaptations, the pigment granules in the secondary pigment cells and retinula cells migrate distally, with a decrease in the length of crystalline tract.

Ovipositional responses of tortricid moths to sugars, salts and neem oil

Oviposition is essential in the life history of insects and is mainly mediated by chemical and tactile cues present on the plant surface. Oviposition deterrents or stimulants can modify insect oviposition and be employed in pest control. Relatively few gustatory oviposition stimuli have been described for tortricid moths. In this study the effect of NaCl, KCl, sucrose, fructose and neem oil on the number of eggs laid by Cydia pomonella (L.), Grapholita molesta (Busck) and Lobesia botrana (Dennis & Schifermüller) was tested in laboratory arenas containing filter papers loaded with 3 doses of a given stimulus and solvent control. In general, salts increased oviposition at the mid dose (102 M) and sugars reduced it at the highest dose (103 mM), but these effects depended on the species. Neem oil dramatically reduced the number of eggs laid as the dose increased, but the lowest neem oil dose (0.1% v/v) increased L. botrana oviposition relative to solvent control. Our study shows that ubiquitous plant chemicals modify tortricid moth oviposition under laboratory conditions, and that neem oil is a strong oviposition deterrent. The oviposition arena developed in this study is a convenient tool to test the effect of tastants on the oviposition behavior of tortricid moths.