Journal of Pest Science最新文献

Since 2018, increased infestation by the fall armyworm Spodoptera frugiperda (FAW), an invasive pest worldwide, has negatively affected Asian crop production. Seasonal migratory activities drive regional outbreaks of this pest, but it remains unclear whether there is direct transboundary movement between East Asian and South Asian regions. From 2019 to 2023, FAW moth movements were monitored in Ruili of Yunnan Province, a city at the border area of China and Myanmar which is located in the insect migratory route between China and South Asian countries such as India and Bangladesh. The results showed that there was regular seasonal migratory activity of the pest, which could be divided into spring–summer (April–June) and autumn (October) peak migration periods. Further analysis using trajectory simulation model indicated that the FAW moths in spring–summer migration mostly come from Myanmar, the northeastern states of India and Bangladesh, and returns to the three countries in autumn from Southwest China. Our study clarifies the regional migration pattern of the FAW moth in China and South-Southeast Asia, providing a theoretical basis for constructing a regional early warning and management systems of this pest.

The stink bugs Edessa meditabunda, Piezodorus guildinii, and Diceraeus furcatus (Hemiptera: Pentatomidae) are major pests in the Argentinean core area of soybean production. A detailed molecular genetics comprehension of how these insects perceive odorants and respond to semiochemicals and how they detoxify chemical pesticides and plant compounds are essential to improve their management strategies. We first assembled and compared the transcriptomes from E. meditabunda, P. guildinii, and D. furcatus. Regarding sequence similarity, P. guildinii and D. furcatus are closer to each other than E. meditabunda. Then, we characterized the multigene families of odorant binding proteins (OBPs) and cytochrome P450 monooxygenases (CYP). A total of 29, 38, and 39 unigenes encoding for OBP were obtained in E. meditabunda, P. guildinii, and D. furcatus, respectively, divided into classical OBPs and plus-C OBPs. A total of 72, 63, and 76 unigenes encoding for CYP were found in E. meditabunda, P. guildinii, and D. furcatus, respectively, which were further classified into 24 families and 47 subfamilies. On the other hand, we performed for the first time RNA interference in vivo by dsRNA injection in E. meditabunda, suggesting that this molecular tool can be exploited in future physiological and functional studies in this species.

Since the 1990s, the cryptic whitefly (Bemisia tabaci) has been linked to severe viral disease pandemics affecting cassava, a crucial staple crop in eastern Africa. This surge in whitefly populations has also been observed in other crops and uncultivated plants. While previous surveys have connected the increase on cassava to two specific populations, SSA1 and SSA2, the dynamics behind the population growth on other plants remain unclear. Additionally, other B. tabaci species, including EA1, IO, MED, SSA9, and SSA10, have been found on cassava in smaller numbers. This study aimed to identify the host plants that support the growth and development of different B. tabaci in Uganda by collecting fourth-instar nymphs from cassava and 20 other common host plants. Host transfer experiments were conducted to test the ability of seven species (EA1, MEAM1, MED-Africa Silver Leafing (ASL), SSA1-subgroup1, SSA1-Hoslundia, SSA6, and SSA12) to develop on cassava. The identities of the nymphs were determined using partial mitochondrial cytochrome oxidase 1 sequences. Twelve B. tabaci species were identified, including two novel species, based on the 3.5% nucleotide sequence divergence. Cassava was colonised by SSA1-SG1, SSA1-SG2, and SSA2. The most prevalent species were SSA1-SG1, MED-ASL, and SSA13, which were also the most polyphagous, colonising multiple plant species. Several whitefly species colonised specific weeds, such as Aspilia africana and Commelina benghalensis. The polyphagous nature of these species supports continuous habitats and virus reservoirs. Effective management of whitefly populations in eastern Africa requires an integrated approach that considers their polyphagy and the environmental factors sustaining host plants.

The Varroa destructor mite causes severe losses of Apis mellifera colonies, requiring recurring treatments. One such treatment is oxalic acid (OA), considered ecological. However, it is unclear whether OA affects the honey bee gut microbiota or other hive-associated microbiotas. Herein, we studied the effect of three OA treatments (trickling at 2.1% or 4.2%, and sublimation through Varrox®) upon microbial communities associated with workers’ gut, hive bee bread and pupae, sampled from conventionally or ecologically managed colonies under different anthropization levels (located in urban, rural or mountainous landscapes). We hypothesized that treatment with OA would impact the diversity and composition of bacteria and/or eukaryotic communities, and that the effect would be dose-dependent and specific to the beehive niche. Results showed that the microbiomes of apiaries under different anthropization levels and management strategies differed prior to OA application. Neither the bacterial nor the fungal communities of bee bread and pupae shifted due to OA treatment. Independent of the dosage and the application method (trickling or sublimation), OA induced slight compositional changes in the bacterial profiles of honeybee guts. Those changes were stronger the higher the anthropization (in colonies from urban areas under conventional management). OA treatment reduced the relative abundance of several pathogens, such as Nosema ceranae, and decreased the overall bacterial diversity down to values found in less anthropized colonies. Thus, our results suggest that, aside from managing Varroa infestations, OA could have beneficial effects for stressed colonies while not impairing honey bee resilience from a microbial point of view.

The activity of Cinnamomum cassia essential oil (EO) and (E)-cinnamaldehyde was investigated on the phytoparasitic species Meloidogyne incognita, Globodera rostochiensis, and Xiphinema index. Juveniles (J2) or eggs of M. incognita and G. rostochiensis and mixed-age specimens of X. index were exposed to 12.5–100 µg mL⁻¹ concentrations of the two products. The suppressiveness of soil treatments with 100–800 mg kg⁻¹ soil rates of the C. cassia EO and (E)-cinnamaldehyde to M. incognita and G. rostochiensis was assessed on potted tomato and potato, respectively. A 24-h exposure to a 12.5 µg mL⁻¹ solution of (E)-cinnamaldehyde resulted in more than 68% mortality of M. incognita J2, while a poor mortality occurred at the same concentration of the whole EO. The mortality of G. rostochiensis J2 ranged 39 and 42%, respectively, since after a 4-h exposure to a 12.5 µg mL⁻¹ solution of both products. All the X. index specimens died after a 48- and 8-h exposure to a 100 µg mL⁻¹ solution of the EO and (E)-cinnamaldehyde, respectively. Egg hatch was reduced by more than 90% after exposing the M incognita egg masses or the G. rostochiensis cysts to 800 µg mL⁻¹ concentration of both EO and (E)-cinnamaldehyde for 24 and 96 h, respectively. The infestation of M. incognita and G. rostochiensis on tomato and potato, respectively, was significantly reduced by all soil treatments with both products, though (E)-cinnamaldehyde generally resulted more suppressive than the whole EO to both nematode species. According to these results, C. cassia EO and (E)-cinnamaldehyde could be suggested as a potential source of new environment-friendly nematicides.

Metal phosphides, particularly aluminium phosphide (AlP) and zinc phosphide (Zn₃P₂), are widely used in low- and middle-income countries (LMICs) as rodenticides in urban and domestic environments due to their low cost and high toxicity to rodent pests. However, they are also highly toxic to humans with no antidote available and have been associated with numerous fatal cases of intentional and accidental poisoning. This paper reviews alternatives to metal phosphide use for rodent pest management in urban and domestic environments, highlights case studies of effective alternative approaches, and provides recommendations for research and policy. This review identifies numerous alternative methods available for managing rodent pests in domestic/urban settings that can replace metal phosphides. These include chemical methods, i.e. rodenticides, and non-chemical methods, e.g. rodent-proofing, sanitation and trapping. However, because the majority of chemical rodenticides qualify as highly hazardous pesticides due to acute human health toxicity, environmental toxicity, and/or bioaccumulation, simply selecting substitute chemical rodenticides to replace metal phosphides are likely to replace one set of hazards with others. Thus, careful risk and hazard assessments are needed when considering substituting with other chemicals. Overall, we need to move away from current levels of rodenticide reliance towards more integrated and ecologically based approaches.

The use of Bacillus volatiles to manage root-knot nematodes (RKNs) is a topic that gained extensive attention because it is safe and environmentally benign. Bacillus velezensis TA-1, isolated from a continuously cropped soil, exhibited strong nematicidal activity against RKNs in vitro and in field conditions. However, it remains poorly understood whether TA-1 volatile organic compounds (VOCs) could be effective against Meloidogyne incognita. In this study, the results of chemotaxis activity test revealed that B. velezensis TA-1 exhibited strong repellent effects on second-stage juveniles (J2s) of M. incognita. In in vitro assays, TA-1 VOCs in a three-compartment Petri dish assay exhibited a mortality rate of 84.1% at 48 h and 92.8% at 72 h to M. incognita J2s. Further evidence revealed that TA-1 VOCs significantly inhibited the gene expression of mpk-1, flp-18 and ord-1 by 61.0%, 44.8% and 54.5%, respectively. Moreover, TA-1 VOCs increased the content of reactive oxygen species (ROS), resulting in severe oxidative stress and death of nematodes. Results from a double-layered greenhouse experiment indicated that the populations of J2s in the soil and in cucumber roots were notably reduced by TA-1 VOCs compared to the untreated control. Furthermore, eleven VOCs were identified from TA-1 by solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC/MS) analysis, of which benzaldehyde, 2-decanol, and 2-undecanone had strong contact nematicidal activities against M. incognita J2s. In addition, benzaldehyde and 2-dodecanone exhibited fumigation effects on M. incognita J2s. Overall, these results demonstrated that TA-1 VOCs exhibited direct contact nematicidal and fumigation activities against RKNs and could be considered as potential biocontrol agents for the control of RKNs.

Plants use various secondary chemicals in their chemical defense against herbivores. While botanical insecticides are crucial for reducing the reliance on chemical pesticides, the development of plant-derived insecticides remains limited. In this study, we fed Henosepilachna vigintioctopunctata with three different host plants (Solanum nigrum, Solanum tuberosum, and Physalis floridana) and observed that feeding on P. floridana led to changes in the body size and a significantly high mortality rate. Through transcriptome analysis, it was found that the trehalose metabolism pathway of H. vigintioctopunctata changed significantly under different host feeding conditions, especially since the expression level of the trehalase gene was extremely different. We subsequently identified eight transcripts of HvTREs and analyzed their evolution and structure. Among them, significant differences are observed in the relative expression levels of HvTRE1-5 in H. vigintioctopunctata after the fourth instar and were affected by different plant diets. Compared with the natural host S. nigrum, the larvae that fed on P. floridana significantly reduced the contents of trehalose, glucose and glycogen and significantly affected the trehalase activity. Knockdown of HvTRE1-5 by RNAi increased mortality at the H. vigintioctopunctata prepupation stage, suggesting that HvTRE1-5 is important for H. vigintioctopunctata pupation. This study provides new insights into developing of green control methods for H. vigintioctopunctata and offers a valuable example for understanding the interaction between host plants and herbivorous insects.

Pyrethroids, targeting the voltage gated sodium channel (VGSC), are fundamental for the control of arboviral disease circulation. The spread of pyrethroid resistance among vector species represents thus a major public health concern. Culex pipiens is one of the most abundant European mosquito species and main vector of West Nile virus, leading cause of arboviral encephalitis worldwide. Despite this, monitoring of its resistance status and the understanding of underlying mechanisms are widely neglected. Herein, we performed an oligo-hybridization capture approach on 82 Cx. pipiens specimens from Italy and Greece to investigate the whole coding sequence of the vgsc gene for the presence of known and potential knock-down resistance (kdr) mutations associated with target-site resistance to pyrethroids in insects. Among the 26 non-synonymous substitutions revealed by the analysis, the super-kdr haplotype—i.e. the association of kdr-alleles 918T and 1014F, known for conferring a strongly enhanced resistance phenotype in Musca domestica – was revealed for the first time in mosquitoes. Three more potential kdr alleles were detected for the first time in Cx. pipiens and multiple kdr variants were observed for locus 1014, with allele 1014F, reaching frequencies > 80%. Overall, results depict a worrisome situation that could affect the ability to control West Nile virus outbreaks in southern Europe. To avoid this, resistance monitoring needs to be intensified and an enhancement of the diagnostic tool box for the easy detection of different kdr-variants (including in particular the super-kdr haplotype) and for subsequent functional studies on the resistance phenotype of detected variants, is required.

Mass trapping can be a crucial component of a push–pull strategy, which involves deterrence of pests from a crop (push), while luring them toward an attractive source e.g., a trap (pull). In this study, we explored the effect of blue and blue + UV LEDs on the dispersal of greenhouse whiteflies settled on tomato plants (“push” factor) and the contribution of a yellow sticky trap (YST) and a green LED-enhanced YST (green LED trap) on their recapture after take-off (“pull” factor), in controlled conditions. In following scaling-up experiments in the greenhouse, we tested the effect of different blue spotlight arrangements and intensities on whitefly dispersal, in the presence of a green LED trap. Number of dispersed and trapped whiteflies was counted and the results revealed that blue and blue + UV LEDs increased the dispersed whiteflies by twofold compared to the control without deterrent LEDs and 87–90% of them were captured on a green LED trap. In the greenhouse, high-intensity blue spotlights (186 μmol/m²/s) deterred nearly 50% of whiteflies from the plants and more than half of them were recaptured, regardless the different arrangement of the blue spotlights. The green LED trap was at least twice as attractive as the YST, and in the greenhouse, it captured nearly 12 times more whiteflies in the presence of high-intensity deterrent blue spotlights, compared to the control. These findings provide significant implications for improving targeted whitefly control techniques and can lead to the development of new push–pull strategies.