Key Agricultural Pest Research Articles

Morphological and molecular characterization of Purpureocillium lilacinum along with its biopesticidal effect against fall armyworm (Spodoptera frugiperda) in Southern Taiwan

BackgroundFall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), a key agricultural pest, impacts a broad spectrum of crop species, such as cotton, maize, rice, sorghum, and a range of vegetables. Chemical pesticides and transgenic maize are commonly used to protect crops against this major pest. However, biological control offers a safer and more sustainable solution for long-term FAW management. Entomopathogenic fungi (EPF), a substitute for synthetic insecticides, have been proven to be an effective biocontrol agent for managing pest populations. The present study objective is to isolate and identify the EPF, Purpureocillium lilacinum from soil using morphological and molecular techniques and evaluate its pathogenicity against FAW eggs and various larval stages under different spore concentrations.ResultsThe micro-morphological characteristics fluctuated in growth behavior, appearance, and color under diverse growth media and temperatures. Molecular analysis, which involved constructing a phylogenetic tree from ITS and TEF gene regions, confirmed that PT-02 was P. lilacinum. The pathogenicity of the fungus was tested on FAW eggs, neonates, and larvae at multiple concentrations (1 × 108, 1 × 107, and 1 × 106 spores/ml), resulting in variation mortality. The egg mortality rate at 1 × 108, 1 × 107, and 1 × 106 spores/ml was 98, 98 and 96%, respectively. The neonate mortality rate was 100%, while first and second instars larvae mortality ranged from 10–36% across three concentrations, seven days after treatment (DAT). The median lethal concentration (LC50) values of P. lilacinum PT-02 against FAW eggs, first and second instars, were 3.02 × 107, 1.38 × 108, and 2.56 × 108 spore/ml, respectively.ConclusionsThe findings revealed that the native strain of P. lilacinum exhibited strong virulence against FAW, suggesting its potential use as an effective biocontrol agent for managing field pest populations.

RNAi targeting Nav and CPR via leaf delivery reduces adult emergence and increases the susceptibility to λ-cyholthin in Tuta absoluta (Meyrick)

The tomato leafminer, Tuta absoluta (Meyrick), one of the most economically destructive pests of tomato, causes severe yields losses of tomato production globally. Rapid evolution of insecticide resistance requires the development of alternative control strategy for this pest. RNA interference (RNAi) represents a promising, innovative control strategy against key agricultural insect pests, which has recently been licensed for Colorado Potato Beetle control. Here two essential genes, voltage-gated sodium channel (Nav) and NADPH-cytochrome P450 reductase (CPR) were evaluated as targets for RNAi using an ex vivo tomato leaf delivery system. Developmental stage-dependent expression profiles showed TaNav was most abundant in adult stages, whereas TaCPR was highly expressed in larval and adult stages. T. absoluta larvae feeding on tomato leaflets treated with dsRNA targeting TaNav and TaCPR showed significant knockdown of gene expression, leading to reduction in adult emergence. Additionally, tomato leaves treated with dsRNA targeting these two genes were significantly less damaged by larval feeding and mining. Furthermore, bioassay with LC30 doses of λ-cyholthin showed that silencing TaNav and TaCPR increased T. absoluta mortality about 32.2 and 17.4%, respectively, thus indicating that RNAi targeting TaNav and TaCPR could increase the susceptibility to λ-cyholthin in T. absoluta. This study demonstrates the potential of using RNAi targeting key genes, like TaNav and TaCPR, as an alternative technology for the control of this most destructive tomato pests in the future.

Systematic analysis of hyperspectral imaging and intelligent sensor systems in multiscale agriculture

This article delves into the systematic analysis of Hyperspectral Imaging Technology (HSI) and Intelligent Sensor Systems in the context of multiscale agriculture, showcasing their critical role in enhancing efficiency and sustainability in agricultural production amid the challenges posed by global population growth. It highlights the pressing need to optimize agricultural processes through advanced technologies to tackle issues such as resource scarcity and environmental pollution. By presenting case studies, the article illustrates the effective integration of HSI and intelligent sensors in key agricultural processessoil analysis, crop monitoring, and pest detectionunderscoring their significance in advancing precision agriculture. The discussion extends to the potentials of data fusion and decision support systems in elevating crop yield and quality. Concluding, the paper emphasizes that despite facing hurdles like technical barriers and maintenance costs, the application of these technologies not only boosts production efficiency and precision but also contributes to agricultural sustainability, underlining the importance of continued research and innovation for a more sustainable and efficient agricultural future.

Machine learning provides insights for spatially explicit pest management strategies by integrating information on population connectivity and habitat use in a key agricultural pest.

Insect pests have garnered increasing interest because of anthropogenic global change, and their sustainable management requires knowledge of population habitat use and spread patterns. To enhance this knowledge for the prevalent tea pest Empoasca onukii, we utilized a random forest algorithm and a bivariate map to develop and integrate models of its habitat suitability and genetic connectivity across China. Our modeling revealed heterogeneous spatial patterns in suitability and connectivity despite the common key environmental predictor of isothermality. Analyses indicated that tea cultivation in areas surrounding the Tibetan Plateau and the southern tip of China may be at low risk of population outbreaks because of their predicted low suitability and connectivity. However, regions along the middle and lower reaches of the Yangtze River should consider the high abundance and high recolonization potential of E. onukii, and thus the importance of control measures. Our results also emphasized the need to prevent dispersal from outside regions in the areas north of the Yangtze River and highlighted the effectiveness of internal management efforts in southwestern China and along the southeastern coast. Further projections under future conditions suggested the potential for increased abundance and spread in regions north of the Yangtze River and the southern tip of China, and indicated the importance of long-term monitoring efforts in these areas. These findings highlighted the significance of combining information on habitat use and spread patterns for spatially explicit pest management planning. In addition, the approaches we used have potential applications in the management of other pest systems and the conservation of endangered biological resources. © 2024 Society of Chemical Industry.

Bemisia tabaci MEAM1 still remains the dominant species in open field crops in Brazil.

Among Bemisia tabaci species, the invasive MEAM1 and MED species are key agricultural pests for many crops. In Brazil, most part of B. tabaci population outbreaks were associated with MEAM1, which, since 1990s quickly spread across the entire country. Later in 2014, the MED was identified in Brazil, initially more restricted to greenhouses, but suddenly reaching new areas in the South and Southeast open regions. Thus, our objective was to investigate the geographical distribution of MEAM1 and MED on open field crops in Brazil. MEAM1 is still the predominant species on open field crops such as soybean, cotton, and tomato. The sequencing of a cytochrome c oxidase subunit I (COI) gene fragment revealed a single haplotype of MEAM1, suggesting the establishment of a single MEAM1 strain in the country. The haplotypes found for MEAM1 and MED are genetically related to the globally dispersed strains, Jap1 and Mch1, respectively. Continuous monitoring of B. tabaci species is crucial because landscape alterations, climatic changes, and pest management methods may shift the B. tabaci species distribution and dominance in Brazilian crop areas.

Evaluation of Life Cycle of Gram Pod Borer Helicoverpa armigera (Hubner) on Vegetable Pea

Pulse crops are faced with a major biotic constraint globally, and they are attacked by Helicoverpa armigera (Hübner) (Noctuidae), also known as the pod borer, across various regions including Asia, Europe, Africa, Australia, and South America. It is widely recognized as a key agricultural pest. Study of their life cycle revealed that total larval period were recorded (20.00±3.21) days from 1st instar to 6th instar under laboratory conditions at 26°C with 65 % relative humidity revealed. The mean duration was (2.66±0.33), (2.66± 0.33), (2.33± 0.33), (3.66± 0.88), (4.33± 0.66), and (4.33±0.88) days of 1st , 2nd , 3rd, 4th ,5th and 6th larval instar respectively during April-May 2022.The average incubation period of egg ranged from(4.66±0.88) days. The pod borer passes through six larval instars to become an adult.

Emerging trends in insect sex pheromones and traps for sustainable management of key agricultural pests in Asia: beyond insecticides—a comprehensive review

Emerging trends in insect sex pheromones and traps for sustainable management of key agricultural pests in Asia: beyond insecticides—a comprehensive review

Genetic connectivity constrained by natural barriers in a key agricultural pest: insights from mitochondrial DNA analysis

In the context of anthropogenic global change, the study of landscape effects on species movement has garnered increasing attention. Landscape genetics offer indirect yet attractive means to capture species dispersal events across generations and their interaction with landscapes. However, landscape genetic patterns tend to exhibit significant variations across taxa and rely on the molecular makers adopted. Here, we investigated how landscapes influence population connectivity of an important tea pest, Empoasca onukii, using mitochondrial DNA sequences of 1,518 individuals from 57 locations in mainland China and offshore islands. We analyzed the inter-population genetic divergence and integrated multiple models to explicitly quantify their association with geographic distance, environmental heterogeneity, and landscape barriers. Analyses revealed a reduction in gene flow on islands, along the Yangtze River, and across mountainous regions of Western China. Models explicitly detected the predominant contributions of topographic complexity to population divergence and evidenced that mountains may serve as effective dispersal barriers for E. onukii. These results suggest that the limited gene exchange resulting from low population connectivity among mountains might generate the observed patterns of mitochondrial genetic variations, which contrasts the climate-related pattern previously observed on microsatellites. The findings enhance our comprehension of the evolutionary and epidemic dynamics of E. onukii, and highlight the demand of considering species-specific traits when studying population landscape genetic patterns. Moreover, the study emphasizes the necessity of employing multiple molecular markers to comprehensively elucidate landscape effects on population connectivity across diverse species for valuable insights into biodiversity conservation, pest control, and other management decisions.

Vibrational calling signals improve the efficacy of pheromone traps to capture the brown marmorated stink bug

Halyomorpha halys (Stål, 1855), the brown marmorated stink bug (BMSB), is an invasive species that has become a key agricultural pest in its invaded range. Commercial traps available for BMSB monitoring rely on male produced aggregation pheromones as lure, with two possible shortcomings: trap spillover and low detection precision. In this study, we assessed if vibrational signals can increase the attractiveness of pheromone traps by testing the optimized vibration-based lure (Female Song 2, FS2) associated with a specifically designed trap (i.e., the vibrotrap). We evaluated the efficacy of this bimodal trap (i.e., pheromones + vibrations) on females, males and nymphs in controlled conditions (greenhouse) and in the field, in two sites at the margin of two commercial vineyards. In the field, bimodal vibrotraps were compared to three unimodal (i.e., only pheromone) trap types. Both experiments showed that the vibrotrap is highly attractive for BMSB, and the optimized FS2 signal significantly improved its effectiveness. Even though FS2 was selected to target males, the number of trapped females increased as well. Overall, the presented findings show a feasible improvement to future commercial BMSB traps through the synergic use of semiophysicals and semiochemicals. Further research is needed to evaluate the effectiveness of vibrotraps for both early detection and mass trapping.

Effect of temperature and cassava genotype on the development, fecundity and reproduction of Bemisia tabaci SSA1

The Bemisia tabaci complex is currently recognised as key agricultural pests that cause economic damage globally. Temperature is the most important driver of changes in behaviour, abundance and distribution of insect pests, including the whitefly (Bemisia tabaci). The objective of this study was to evaluate the development, fecundity and reproduction of B. tabaci SSA1 on cassava genotypes under a range of temperatures. A laboratory study was conducted using three cassava genotypes (Alado alado, NAROCASS 1 and NASE 14) at five constant temperatures (16, 20, 24, 28 and 32 °C). The parameters assessed included development duration, survival, fecundity and population parameters for B. tabaci SSA1. Temperature had significant effects (P<0.001) on development time, survival and fecundity of B. tabaci; while cassava genotype had no effect (P>0.05). An inverse relationship was observed between development time and temperature for all stages across all cassava genotypes. The total life cycle was 63.8 days at 16 °C and 17.9 days at 32 °C on NAROCASS 1. Survival for each stage throughout the entire life cycle increased with temperature and was highest at 32 °C, although this was not significantly different from that at 28 °C. Fecundity increased with temperature and was highest at 32 °C on all cassava genotypes. For all cassava genotypes, the intrinsic rate of increase (rm), finite rate of increase (l) and net reproductive rate (Ro) increased with temperature, while mean generation time (T) reduced following a similar pattern. At 32 °C, rm, Ro, l and T were 0.2, 48.7, 1.2 and 22.6 days, respectively; compared to 0.01, 1.9, 1.0 and 71.2 days at 16 °C on Alado alado. Therefore, the ideal development temperature for B. tabaci SSA1 is 32 °C. Thus, there is a risk of accelerated future expansion of B. tabaci SSA1 populations globally, with global warming and climate variability.

Overlooked lacewings in biological control: The brown lacewing Micromus angulatus and the green lacewing Chrysopa formosa suppress aphid populations in pepper

AbstractLacewings are important natural enemies of soft‐bodied arthropods. Chrysopidae and Hemerobiidae in particular include promising biological control agents of key agricultural pests. Here, we evaluated the efficacy of larvae and adults of the brown lacewing Micromus angulatus and the green lacewing Chrysopa formosa in controlling the green peach aphid Myzus persicae under laboratory conditions. We found that the release of the first instar larvae of both species at the rate of 2 or 10 individuals per pepper plant was effective in reducing the populations of M. persicae, irrespectively of the initial pest infestation pressure, i.e., 10 or 20 aphids per plant. The brown lacewing larvae at the highest release rate managed to completely eliminate the aphids from the pepper plants within two weeks following release. Adult lacewings of both species released at a rate of one to two females per plant were also effective in drastically reducing of M. persicae populations. Our results highlight the potential of these two widespread but overlooked lacewing species for use in biological pest control.

Manipulation of Gut Symbionts for Improving the Sterile Insect Technique: Quality Parameters of Bactrocera dorsalis (Diptera: Tephritidae) Genetic Sexing Strain Males After Feeding on Bacteria-Enriched Diets.

One environmentally friendly method used to manage Bactrocera dorsalis (Hendel), a key agricultural pest of substantial economic importance, is the sterile insect technique (SIT). Nevertheless, several deficiencies related to this strategy impair the success of the SIT, including the inferior performance of released sterile males compared with wild males, which could be partly solved by the utilization of gut symbionts as probiotic dietary components. In this study, a culture-dependent method was used to isolate and characterize gut-associated bacterial species in adult B. dorsalis genetic sexing strain (GSS) males. In addition, three bacterial isolates from the Enterobacteriaceae family, namely, Enterobacter sp., Morganella morganii, and Moellerella wisconsensis, were used as supplements in larval and adult diets to assess their effects on the life-history traits of irradiated males. Consistent with many previous studies, Enterobacter spp. was shown to be beneficial, with some quality control indices, such as adult size, pupal weight, survival rate under stress and nutritionally rich conditions, and mating competitiveness, being significantly increased, while slight nonsignificant increases in emergence rate and flight ability were observed. Conversely, the M. morganii and M. wisconsensis strains both had negative effects on irradiated male fitness and mating competitiveness. Our results, in combination with those of earlier studies, can contribute to improving the effectiveness of SIT application by enhancing the different aspects of augmentative rearing and biological traits of pests under laboratory rearing conditions.

Characterization of a New Set of Microsatellite Markers Suggests Polygyny and Polyandry in Atta cephalotes (Hymenoptera: Formicidae).

The leaf-cutting ant, Atta cephalotes L. (1758), is a major herbivore with great economic impact in the Neotropics. Because of its broad range and human-mediated dissemination, the ecology of this ant has received considerable attention; however, questions concerning its population genetics, dispersal, and social structure remain unexplored. Here, we aimed to identify and provide information on molecular and statistical performance of a suite of polymorphic microsatellite markers for A. cephalotes while demonstrating their utility for further genetic studies. We designed primer sequences targeting thousands of microsatellite loci and then screened 30 of these for amplification and polymorphism. Fifteen of these loci were selected and used to evaluate their polymorphism using 74 ants sampled from 15 different nests of the same location. This set of 15 loci exhibited variation of 2-20 alleles, with a mean heterozygosity of 0.57. All loci followed Hardy-Weinberg expectations with no evidence of linkage disequilibrium, while two loci showed evidence of null alleles. Our preliminary analysis suggested substantial nest differentiation with no population viscosity within the sampled location, as well as colonies with multiple queens (polygyny) and paternity (polyandry). Our newly identified microsatellites have proven to be highly informative to investigate gene flow, social structure and reproduction of this key agricultural pest.

Assemblage of the Egg Parasitoids of the Invasive Stink Bug Halyomorpha halys: Insights on Plant Host Associations.

Simple SummaryThe Brown Marmorated Stink Bug (BMSB), Halyomorpha halys, is an invasive polyphagous species that causes extensive damage to fruits and vegetable crops. Available chemical treatments and mechanical measures are often insufficient to keep this pest under control. In the last decade, the scientific community has made several efforts in order to identify and select suitable natural enemies to use in biological control program. Several native and exotic parasitoid species attacking H. halys eggs have been registered in the invaded countries. In this study, the distribution of these parasitoids was examined in Trentino-Alto Adige, in Northern Italy, by combining two different methods. The research revealed the presence of seven parasitoid and one hyperparasitoid species, which are present in different contexts and on several host plants. The most abundant species, Anastatus bifasciatus and Trissolcus mitsukurii, showed different patterns in distribution, with a higher presence of A. bifasciatus in urban areas and Tr. mitsukurii in orchards. Our results proved that H. halys natural enemies are adapted to the environmental conditions of the study area. The gathered data on the plant host-associations will support the development of future biological control programs.Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive alien species and a key agricultural pest. Its native parasitoids (Trissolcus japonicus Ashmead and Tr. mitsukurii Ashmead) have been registered in several countries where H. halys brought dramatic economic losses and where biological control is considered to be the most effective long-term solution. By searching for stink bug egg masses and exposing sentinel egg masses, we monitored the distribution of native and exotic egg parasitoids in Trentino-Alto Adige (Italy), an area where both the host and parasitoids are in expansion. We recorded ten pentatomids, seven parasitoid species, with the first report of Tr. japonicus in this area and a hyperparasitoid. In the assemblage, Anastatus bifasciatus (Geoffroy) and Tr. mitsukurii were the dominant parasitoids, with a different distribution in terms of context and host plants. Sycamore was the host plant where the highest number of naturally laid parasitized egg masses (26%) were recorded. Trissolcus mitsukurii showed the highest parasitism rate, and was often found in apple orchards. The emergence of exotic parasitoids showed a temporal delay compared to native ones. Sequence analysis of 823 bp of the CO1 mitochondrial gene revealed that the recovered Tr. japonicus and Tr. mitsukurii harbored one single haplotype each. These haplotypes were previously found in 2018 in Northern Italy. While sentinel egg masses proved to be very effective in tracking the arrival of exotic Trissolcus species, the collection of stink bug egg masses provided fundamental data on the plant host species. The results lend strong support to the adaptation of exotic Trissolcus species to the environmental conditions of the range of introduction, providing new information on plant host-associations, fundamental for the development of biological control programs.

Molecular identification of <i>Helicoverpa armigera</i> (Hubner) associated with tomatoes (<i>Solanum lycopersicum L.</i>) in Ogun State

The tomato fruit worm Helicoverpa armigera is a key polyphagous agricultural pest with a worldwide distribution. Apart from tomatoes, H. armigera also infests cotton, maize, chickpea and pigeon-pea. Its larvae affect almost all the aerial parts of tomato plants from the vegetative stage to the fruit maturation stage. Due to its high mobility, it causes a huge damage on crops and, as such, early detection of H. armigera from different agro-ecosystems is crucial for implementing control measures. Herein, we used a molecular marker approach to identify Helicoverpa spp. collected from twelve different locations in Ogun State. The H. armigera larvae used for the molecular identification were collected on tomato fruits from the 12 different locations from three agro-ecological zones in Ogun State. Genomic DNA of Helicoverpa was extracted and its purity was checked using Nanodrop spectrophotometer. Cytochrome Oxidase-I (CO-I) region of the DNA was subjected to Polymerase Chain Reaction (PCR) amplification. The PCR amplification of the CO-I gene after gel electrophoresis of PCR products of H. armigera showed a similar banding pattern at 700 base pairs which confirmed the insect as H. armigera.
 Keywords: Helicoverpa armigera, Deoxyribonucleic acid, Cytochrome Oxidase-I, Polymerase Chain Reaction, Electrophoresis.

Tying pest insects in knots: the deployment of spider-venom-derived knottins as bioinsecticides.

Spider venoms are complex chemical arsenals that contain a rich variety of insecticidal toxins. However, the major toxin class in many spider venoms is disulfide-rich peptides known as knottins. The knotted three-dimensional fold of these mini-proteins provides them with exceptional chemical and thermal stability as well as resistance to proteases. In contrast with other bioinsecticides, which are often slow-acting, spider knottins are fast-acting neurotoxins. In addition to being potently insecticidal, some knottins have exceptional taxonomic selectivity, being lethal to key agricultural pests but innocuous to vertebrates and beneficial insects such as bees. The intrinsic oral activity of these peptides, combined with the ability of aerosolized knottins to penetrate insect spiracles, has enabled them to be developed commercially as eco-friendly bioinsecticides. Moreover, it has been demonstrated that spider-knottin transgenes can be used to engineer faster-acting entomopathogens and insect-resistant crops. © 2019 Society of Chemical Industry.

Origanum syriacum subsp. syriacum: From an ingredient of Lebanese ‘manoushe’ to a source of effective and eco-friendly botanical insecticides

Origanum syriacum subsp. syriacum, also known as ‘Za’tar’ is an aromatic shrub native to Lebanon and cultivated in other Middle East countries. The plant leaves enjoy a high reputation as a traditional remedy against cardiovascular, respiratory and infectious diseases. In addition, they are a famous component of the Lebanese pizza (“manoushe”). Starting from its safety for humans, here O. syriacum subsp. syriacum was selected to assess the insecticidal efficacy of its leaf essential oil (EO) and its major constituent carvacrol against two key agricultural pests, namely the noctuid Spodoptera littoralis and the aphid Myzus persicae, as well as on the fly pest Musca domestica. Furthermore, the Za’tar EO potential impact on beneficial organisms such as the aphid predator Harmonia axyridis and the earthworm Eisenia fetida, which is used in the vermicomposting process, was assessed. GC–MS analysis highlighted the phenolic monoterpene carvacrol as the predominant component (83%) of Za’tar EO. Toxicity of O. syriacum subsp. syriacum EO was noteworthy, showing LC50/LD50 of 103.3 μg larva−1, 2.1 mg L−1 and 58.7 μg adult−1 on S. littoralis, M. persicae and M. domestica, respectively, which were partly consistent with those of its major component carvacrol (38.3 μg larva-1, 1.6 mL L−1 and 59.3 μg adult-1, respectively). When tested up to 3.8 mL L−1 and 200 mg kg−1 on H. axyridis and E. fetida, this EO was not toxic, at variance with α-cypermethrin, which caused 100% mortality at 1 mL L−1 and 25 mg kg−1, respectively. Taken together, these results promote carvacrol-rich Za’tar EO as a promising reservoir of green insecticides to be used for managing insect pests and vectors of economic relevance.

Induced Resistance Against Western Flower Thrips by the Pseudomonas syringae-Derived Defense Elicitors in Tomato.

Western flower thrips (WFT) Frankliniella occidentalis (Pergande) is a key agricultural pest of cultivated tomatoes. Induced host plant resistance by activating jasmonic acid (JA) signaling pathway constitutes a promising method for WFT control. The phytotoxin coronatine (COR), produced by Pseudomonas syringae pv. tomato DC3000 (Pst), mimics the plant hormone JA-Isoleucine and can promote resistance against herbivorous arthropods. Here we determined the effect of Pst and COR on tomato resistance against WFT, induction of JA and salicylic acid (SA) associated defenses, and plant chemistry. Additionally, we investigated the presence of other components in Pst-derived and filtered culture medium, and their interactive effect with COR on tomato resistance to WFT. Our results showed that infiltration of COR or Pst reduced WFT feeding damage in tomato plants. COR and Pst induced the expression of JA-associated gene and protein marker. COR also induced expression of a SA-related responsive gene, although at much less magnitude. Activation of JA defenses in COR and Pst infiltrated plants did not affect density of type VI leaf trichomes, which are defenses reported to be induced by JA. An untargeted metabolomic analysis showed that both treatments induced strong changes in infiltrated leaves, but leaf responses to COR or Pst slightly differed. Application of the Pst-derived and filtered culture medium, containing COR but not viable Pst, also increased tomato resistance against WFT confirming that the induction of tomato defenses does not require a living Pst population to be present in the plant. Infiltration of tomato plants with low concentrations of COR in diluted Pst-derived and filtered culture medium reduced WFT feeding damage in a greater magnitude than infiltration with an equivalent amount of pure COR indicating that other elicitors are present in the medium. This was confirmed by the fact that the medium from a COR-mutant of Pst also strongly reduced silver damage. In conclusion, our results indicate that induction of JA defenses by COR, Pst infection, the medium of Pst and the medium of a Pst COR- mutant increased resistance against WFT. This was not mediated by the reinforcement of leaf trichome densities, but rather the induction of chemical defenses.

Beyond insects: current status and achievements of RNA interference in mite pests and future perspectives.

Mites comprise a group of key agricultural pests on a wide range of crops. They cause harm through feeding on the plant and transferring dangerous pathogens, and the rapid evolution of pesticide resistance in mites highlights the need for novel control methods. Currently, RNA interference (RNAi) shows great potential for insect pest control. Here, we review the literature regarding RNAi in mite pests. We discuss different target genes and RNAi efficiency in various mite species, a promising Varroa control program using RNAi, the synergy of RNAi with plant defense mechanisms and microorganisms, and current understanding of systemic movement of double-stranded RNA (dsRNA). On the basis of this evidence, we can conclude that there is clear potential for application of RNAi-based mite control, but further research on several aspects of RNAi in mites is needed, including: (i) the factors influencing RNAi efficiency, (ii) the mechanism of environmental RNAi and cross-kingdom dsRNA trafficking, (iii) the mechanism of possible systemic and parental RNAi, and (iv) non-target effects, specifically in predatory mites, which should be considered during RNAi target selection. © 2018 Society of Chemical Industry.

Sexual communication and related behaviours in Tephritidae: current knowledge and potential applications for Integrated Pest Management

Tephritidae are an enormous threat to fruit and vegetable production throughout the world, causing both quantitative and qualitative losses. Investigating mating sequences could help to unravel mate choice dynamics, adding useful information to improve behaviour-based control strategies. We review current knowledge about sexual communication and related behaviours in Tephritidae, with a focus on six key agricultural pests: Anastrepha ludens, Bactrocera cucurbitae, Bactrocera dorsalis, Bactrocera oleae, Ceratitis capitata and Rhagoletis pomonella. We examine features and the role of male–male combat in lekking sites, cues affecting mating dynamics, and some fitness-promoting female behaviours that occur at oviposition sites [the use of oviposition marking pheromones (OMPs) and female–female fights for single oviposition sites]. We outline future perspectives and potential contributions of knowledge about sexual communication to Integrated Pest Management programs for tephritid pests. Sexually selected traits are frequently good indicators of male fitness and knowledge of sexual selection processes may contribute to the improvement of the sterile insect technique (SIT), to select genotypes with high reproductive success and to promote sexually selected phenotypes through mass-rearing optimization. Furthermore, males’ exposure to parapheromones, such as phenyl propanoids (PPs), ginger root oil and trimedlure can enhance the mating success of sterile flies used in SIT programs. PPs are also a powerful tool to improve reduced-risk monitoring dispensers and the male annihilation technique, with low side effects on non-target insects. Lastly, we outline the possibility to sensitise or train mass-reared parasitoids on OMPs during the pre-release phase, in order to improve their post-release performance in the field.