Journal of Pest Science最新文献

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.

The corn leafhopper, Dalbulus maidis (Hemiptera, Cicadellidae), is an important pest of maize in Latin America, transmitting plant pathogens that impact grain production. Recently, mycopesticides have been considered as an alternative for the biological control of D. maidis populations, but there is controversy surrounding the efficacy of these products. We assessed the susceptibility of D. maidis to invertebrate-pathogenic fungi and, for the first time, investigated the protective role of the protein-lipid coat of brochosomes on the insect integument as a barrier against infections. Adult mortality was lower than 35% seven days after exposure to maize plants sprayed with water + surfactant-based conidia suspensions of 31 fungal strains from three different genera (Beauveria, Cordyceps and Metarhizium). Direct application of conidia suspensions on adults did not increase significantly the mortality rates when compared to adults exposed to contaminated surfaces. Conidia in water + surfactant readily adhered and germinated on detached forewings of D. maidis from which brochosomes were removed, but wings coated with this protein-lipid layer repelled droplets. Dry conidia easily adhered to brochosome-coated wings and their germination was not affected, although the methodical self-cleaning behavior of the adults effectively dislodged most conidia (either in suspensions or as a dry powder) from insect’s body after treatment. In conclusion, brochosomes and self-cleaning together efficiently prevent adhesion of conidia to D. maidis cuticle, serving as important barriers against fungal invasion and decreasing insect mortality. Our study highlights the importance of combining mycopesticides with effective adjuvants in spray applications to enhance infection rates and successfully control D. maidis populations.

Plants face an array of insect herbivores and have evolved complex defense approaches against various insect feeding strategies. However, little is known about how plants respond to successive attacks by herbivores with different feeding modes and coordinate their diverse defense mechanisms. In this study, we unveil that inducible jasmonic acid (JA) accumulation in response to leaf-chewing insects augments plant resistance and repellence to sequential leaf-chewing insect (caterpillar) and phloem-feeding insect (whitefly) infestations. Conversely, constitutive and whitefly inducible salicylic acid (SA) accumulation exclusively bolsters defense against later-stage whitefly invasion. Through assessments of herbivore performance and preferences on wild-type, JA-deficient, and SA-deficient plants, we show that JA/SA levels regulate plant resistance to both initial and sequential herbivores. Notably, JA or SA accumulation due to caterpillar or whitefly attacks does not substantially affect constitutive levels of the other compound, despite their antagonistic crosstalk. Furthermore, exogenous JA application in tobacco elicits efficient defense against successive caterpillar and whitefly assaults, surpassing SA's efficacy, albeit with associated growth penalties. Our discoveries demonstrate that plants can tailor their defense strategies against initial and sequential insects with different feeding modes. This customized defense is facilitated by JA/SA responses and their intricate cross-talk while taking account of the growth-defense trade-off.

Moutan Cortex essential oil (MCEO) is considered to be a promising botanical insecticide. However, like most oils, MECO has several limitations, including instability and poor solubility. Nanoencapsulation technology is an excellent strategy for stabilizing essential oils because of its controlled release, enhanced efficacy, and strengthened biological activity. The present study investigated the acaricidal efficacy of pure MCEO and its encapsulated nanoemulsion (NE) and mesoporous silica nanoparticles (MSNs) against the house dust mite Dermatophagoides farinae using contact bioassays, fumigant bioassays, repellent bioassays, and the observation of toxic symptoms. MCEO-MSNs obtained in the study successfully encapsulated MCEO with an encapsulation efficiency of 63.83%. The acaricidal mortality experiments revealed that MCEO-NE and MCEO-MSN showed more significant toxicity against D. farinae than did pure MCEO. The nanomaterials showed better larvicidal and nymphicidal activities than pure MCEO at a high concentration (12-h LC₉₀). Notably, the repellent effect experiment showed that MCEO-NE and MCEO-MSN had long-term and stable repellent effects on D. farinae, indicating the sustained release and persistence of the nanomaterials. More toxicity symptoms were observed in the IM-type group than in the KD-type group, suggesting that the MCEO nanoparticles have adverse effects on the respiratory system. Nanomaterials and MCEO promoted superoxide dismutase (SOD) activity and inhibited acetylcholinesterase (AChE) activity in D. farinae. In addition, the binding sites of paeonol to SOD and AChE were found through molecular docking. These findings demonstrate the potential of MCEO as a biological acaricide, which merits further investigation.

Spodoptera frugiperda is a newly invasive pest in China, often sharing the same feeding niche with native S. exigua. To clarify the competitive displacement, colonization and potential threat to crops by S. frugiperda, the cannibalism and predation behavior, feeding preferences, development and reproduction of both species under laboratory conditions, as well as the population dynamics and damage to maize plants in the field, were studied. Results found that food scarcity intensified interspecific predation between S. frugiperda and S. exigua, but the survival rate of 4th instar S. frugiperda was not significantly influenced (> 93%; P > 0.05). Although S. frugiperda exhibited less aggressive behaviors, its cannibalism coefficient and attack intensity were significantly higher than those of S. exigua (P < 0.05). Moreover, S. frugiperda showed a higher feeding preference for mechanically lethal insects when the maize leaf supply was insufficient. Additionally, a combined diet of maize leaves and lethal insects significantly increased their pupal weight and fecundity (P < 0.05). Field trials showed that when S. frugiperda and S. exigua co-occurred, the population of S. frugiperda at mature stage was similar to that after the intraspecific treatment, and seriously damaged maize plants. These results suggested that interspecific predation by S. frugiperda on S. exigua not only conferred an obvious advantage, but may also promote its development and reproduction, and facilitated its colonization in the invaded area. Our results provide an understanding of the rapid colonization mechanisms of S. frugiperda and will assist development of integrated management strategies.

Tomato chlorosis virus (ToCV) causes widespread infections in tomatoes globally, rapidly spreading in China is closely associated with the dominant whitefly, Bemisia tabaci (Gennadius) Mediterranean (MED). Viruliferous whiteflies have been reported to have shown preference for healthy tomato plants and thus greatly facilitate the spread of this virus. However, the mechanism underlying the change in the host selection behavior is yet unknown. We studied the effects of ToCV infection on the volatile emissions of tomato plants to determine the main volatiles associated with host selectivity by B. tabaci MED. Gas chromatography mass spectrometry (GC-MS) analyses revealed that ToCV infection significantly altered concentrations of 11 volatile compounds. Notably, the attractive p-ethylacetophenone, decreased, while the repellent butylated hydroxytoluene increased. RT-qPCR showed significant expression changes in 10 odorant binding protein (OBP) genes and 11 chemosensory protein (CSP) genes in viruliferous whiteflies compared to non-viruliferous whiteflies. RNA interference indicated that silencing OBP-17 or CSP-1 triggered a strong repellent response from B. tabaci toward tomatoes. Furthermore, OBP-17 expression rose notably with p-ethylacetophenone exposure, with both OBP-17 and CSP-1 exhibiting strong binding affinity for this compound, having dissociation constants of K_{D OBP-17} = 17.24 µmol/L and K_{D CSP-1} = 15.02 µmol/L, respectively. In conclusion, our study revealed dual effects of ToCV on its vectoring whitefly as well as its host plant, which together facilitate the spread of the virus. This novel insight into the epidemiological mechanisms of insect-vectored plant viruses may help to develop new strategies to control these exceedingly important agricultural pests.