Journal of Applied Entomology最新文献

Flue-cured tobacco, Nicotiana tabacum (L.), is often attacked by various pests such as aphids, whiteflies and tobacco budworm. Insecticide application has been the primary method in managing these pests for Yunnan Province. However, it is necessary to look for more sustainable strategies that can help control pests. In this context, conservation biological control is a highly promising alternative, involving the cultivation or conservation of flowering plants within the agricultural ecosystem to attract and support natural enemies. The objective of this study was to evaluate the potential of alyssum, Lobularia maritima (L.) Desv., in attracting natural enemies and managing pests in flue-cured tobacco cultivation. The study conducted two field experiments over successive years, each with of two treatments and three replicates, arranged in a completely randomized design. The treatments were (1) tobacco monoculture and (2) tobacco intercropped with alyssum flower strips. The population density of natural enemies and pests was monitored weekly throughout the study period. The results showed that the presence of alyssum flowers in the tobaccosalyssum treatment significantly increased the abundance of generalist predators such as syrphids, rove beetles, carabids, Orius sp. and spiders during both experiments. This increase in predator population led to a substantial reduction in tobacco pests, particularly aphids. Intercropping alyssum with tobacco can serve as an effective strategy for managing pests specific to the Nicotiana plant, as well as addressing the limited availability of approved insecticides for this crop. This approach may help to mitigate pest-related issues and reduce the reliance on insecticides in tobacco cultivation, contributing to more sustainable pest management practices.

Bean flower thrips (Megalurothrips usitatus) is a major French bean (Phaseolus vulgaris L.) pest. Small-scale farmers manage the pest using mixed plant extracts although their efficacy has not been scientifically validated. We evaluated the efficacy of mixed plant extracts comprising; Capsicum frutescens, Allium sativum, Lantana camara, Tagetes minuta and Azadirachta indica, against M. usitatus under laboratory and screenhouse. We identified and quantified the secondary metabolites associated with insecticidal activity using spectrophotometry and liquid chromatography–mass spectrometry (LC–MS). The plant combinations included PE1 (C. frutescens + A. sativum + L. camara + T. minuta extracts infused for 14 days), PE2 (same as PE1 but infused for 24 h) and PE + N (the five plant extracts infused for 24 h) in distilled water. We used an organic commercial botanical (Pyneem) as a positive control and distilled water as a negative control. Pyneem and PE + N induced the highest mortality at 88% and 77%, respectively, in the laboratory, and 68% and 71%, respectively, in the screenhouse. Phenolics, terpenoids and organosulfur compounds were identified in PE + N and individual plant extracts in varied quantities. These compounds were significantly higher (p < 0.001) in PE + N compared to individual plant extracts. The study showed that PE + N efficiently manages bean flower thrips, and mixing different plant extracts amplifies the secondary metabolites' abundance. The use of mixed plant extracts could be incorporated into integrated pest management strategies for thrips management in legumes. The specific compounds identified in PE + N should be investigated further to understand their modes of action against the pest.

The three ecologically similar species of hemipteran sucking insects, brown planthopper (BPH) Nilaparvata lugens, small brown planthopper (SBPH) Laodelphax striatellus and white-backed planthopper (WBPH) Sogatella furcifera are destructive pests causing severe damage to rice throughout Asia, but they have different host plants that BPH is monophagous insect just feeding rice, WBPH and SBPH are oligophagous insects additionally feeding wheat and barley and SBPH can also feed maize. This study was investigated the gut bacterial communities in BPH, WBPH and SBPH by high-throughput amplicon sequencing in order to explain the differences in host range (SBPH>WBPH>BPH) and feeding habit (BPH with monophagy vs. WBPH and SBPH with oligophagy) of the three ecologically similar species of planthoppers. It was revealed that the gut bacterial flora in BPH was the most complex, and that in SBPH was the simplest. The diversity of the gut bacterial community in BPH was significantly higher than that in WBPH and SBPH, respectively, there was not only significant difference in α-diversity metrics but also in β-diversity metrics. KEGG enrichment analysis furtherly indicated that there was significantly different in the relative abundance of some functional categories (including those related to the biosynthesis of amino acids, fatty acids, lipids and carbohydrate) among BPH, WBPH and SBPH, which were closely related to their nutrient absorption and metabolism. It is presumed that the differences in abundance and composition of the gut bacteria in BPH, WBPH and SBPH may lead to different nutrient absorption and metabolism, which furtherly alter their host range and feeding habit.

The twospotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest of field and greenhouse crops leading to qualitative and quantitative losses. Various chemical-based acaricides are being used for its management that pose risks to human health, environment and non-targeted organisms besides the development of resistance and resurgence of the pests. Therefore, alternative mite management practices are being promoted and implemented. Amongst them, entomopathogenic fungi (EPF) like Beauveria bassiana and Metarhizium spp. are being used globally, although new alternative EPF are required. Keeping this in mind, the present study was comprehended to determine the pathogenicity of native EPF, viz., Tolypocladium inflatum (Hypocreales: Ophiocordycipitaceae) and Clonostachys krabiensis (Hypocreales: Bionectriaceae) against different life stages of TSSM under laboratory conditions. The results indicated that adults are more vulnerable to studied fungi followed by nymphs and eggs of TSSM. The combined application of T. inflatum and C. krabiensis was significantly effective in controlling TSSM adults (99.33%) followed by T. inflatum (93.34%) and C. krabiensis (85.33%). According to the probit analysis, the combined application of studied EPF was found to be more effective against TSSM adults (LC₅₀ = 6.72 × 10⁴ conidia/mL) followed by T. inflatum (LC₅₀ = 1.92 × 10⁶ conidia/mL) and C. krabiensis (LC₅₀ = 7.90 × 10⁶ conidia/mL). All three treatments at higher concentrations significantly reduced the adult and nymph populations. Morphological investigations using scanning electron microscopy revealed the successful conidial adhesion, germination and penetration of native T. inflatum and C. krabiensis conidia on TSSM adults. Thus, the acaricidal potential of isolated native fungi can further be explored for developing fungal-based formulations for the sustainable management of mites.

The greater wax moth, Galleria mellonella L., poses a substantial threat to apiculture, adversely impacting wax quality and potentially acting as a disease vector. There is an urgent need to develop innovative and effective control strategies to address the challenges posed by this pest and ensure the sustainability of the apiculture industry. Spiro-derivative compounds represent a novel class of environmentally safe compounds with high insecticidal properties. For example, they have demonstrated high efficacy against sap-sucking insects such as aphids and whiteflies. However, their effect on chewing insects has not yet been well explored. In this study, we hypothesized that 4-amino-1-azaspiro[4.5]dec-3-en-2-one (4A1AD), a spiro-derivative compound, would exhibit efficacy against G. mellonella larvae. To test this hypothesis, we conducted dipping and feeding bioassays, incorporating varying concentrations of 4A1AD on fourth instar G. mellonella larvae, and recorded mortality, biochemical parameters including total soluble protein content and enzyme activities, and anatomical abnormalities resulting from treatment. Results revealed a significant increase in larval mortality with increased concentrations and treatment durations across both bioassays. Additionally, a significant decrease in protein content and an increase in phenol-oxidase activity were observed with alterations in α and β-esterase activities. Scanning electron microscope findings revealed abnormalities in larval cuticle, spiracular openings and legs. These findings demonstrated the efficacy of 4A1AD, indicating a potential alternative to conventional insecticides in promoting sustainable apiculture practices. Moreover, they provide valuable contributions to the development of novel strategies for effective pest management in apicultural settings.

Biological control of pests can be enhanced by the presence of semi-natural habitats within agricultural landscapes. However, this assumption remains controversial due to inconsistencies related to the type of agroecosystems and the natural enemies studied. Within olive orchards, there is a lack of information regarding the interaction among natural enemies and their relation with habitat structure to control pests at the landscape scale. Here, we investigate the effects of the natural habitat on the pest, pest damage and the interaction of pests and natural enemies – using a trophic guild approach, in organic olive orchards. For this, we decomposed the natural habitats into vegetation structures and analysed their effects with a multi-scale perspective. Our results show that (1) greater proportions of natural habitats increase the abundance of ants (omnivores) and predators and diminish pest pressures – reducing the impact of Prays oleae on olive fruits. (2) Vegetation structures within natural habitats were grouped, based on their effects, into three main vegetation groups: grassland and forest, scrublands and olive trees. However, the dense scrubland and the dense forest improve the abundance of natural enemies that are linked to pest damage the most. (3) Prays oleae increases in landscapes dominated by low numbers of patches that are highly aggregated. Conversely, ants and predators increased in landscapes dominated by high numbers of patches that have a less edge-resembling shape. (4) Within the olive canopy, the abundance of lacewing larvae and salticid spiders is related to lower pest damage and a reduction in P. oleae adults respectively. However, when ants and predators interact with the natural habitat, they can cope with pest pressures without the need for high abundances, supporting ‘the more-effective natural enemy hypothesis’ in agroecosystems.

We provide evidence that Camponotus chilensis (Spinola) visit flowers of the Radal tree (Lomatia hirsuta Diels ex J.F.Macbr.), possibly acting as pollinators of this important tree of the Proteaceae family in the Andean Patagonian forests of Argentina. We found several ant workers transporting pollen from different trees during the blooming season. Pollen transported by workers varied in amount, with some individuals observed fully coated with pollen grains. This note constitutes the first observation of ant activity on the flowers of this plant species and also the first potential example of a tree pollinated by ants in the Neotropics. This note highlights the importance of natural history data in the emergent study field of ant-pollination.

Harmonia axyridis (Pallas), commonly known as the Asian lady beetle, is a native insect species of Asia that has been intentionally introduced to various regions for biocontrol purposes. However, its widespread presence beyond its original release sites suggests a high degree of invasiveness. In this study, we utilized the CRISPR-Cas9 approach to achieve precise genome editing in H. axyridis. Specifically, we targeted two genes in H. axyridis, laccase2 and scarlet, knockdown of which orthologues in other insects showed visible phenotypic changes. The knockout laccase2 resulted not only in an early-detectable phenotype but also in lethality. However, we successfully established a viable and genetically stable mutant colony by disrupting the scarlet gene, resulting in beetles with white eyes. Our findings contribute to the expanding knowledge of genetic manipulation in H. axyridis and provide insights into its potential for future research and practical applications for biocontrol and invasive species management.

The European spruce bark beetle, Ips typographus (L.), is the most important forest pest in Europe due to the profound impacts of periodic outbreaks on ecosystem goods and services. Herein, we evaluated the responses of I. typographus to different doses of verbenone (SPLAT^® Verb, 10% (−)-verbenone by weight; ISCA Inc., Riverside, CA, USA) in traps baited with its aggregation pheromones. Results are based on 1,492,289 I. typographus collected in five experiments over 3 years. SPLAT^® Verb inhibited the response of I. typographus to baited traps out to 14 m from the point of release (dollop) and for >80 days at a dose of 75 g per dollop. Reductions in trap catch ranged from 34% to 93% depending on the dose of verbenone, age of SPLAT^® Verb dollops, distance from dollops and the environment. In forest stands, significant reductions in trap catch were observed at distances up to 14 m from the point of release, with the largest reductions observed at 0 m (93%) and 2 m (64%). In an open area, significant reductions in trap catch were observed at distances up to only 2 m from the point of release, with the largest reduction observed at 0 m (66%). The much lower active inhibitory range of verbenone in the open area appears to be explained by less stable accumulations of verbenone in the surrounding air. There was a significant negative correlation between trap catch and the amount of verbenone measured in air in the vicinity of traps. We also observed inhibition of the sixtoothed spruce bark beetle, Pityogenes chalcographus (L.), another important forest pest in Europe, at all doses (20, 40, 75 and 100 g) of SPLAT^® Verb that were evaluated. The implications of these and other results to the management of I. typographus are discussed.