Journal of Applied Entomology最新文献

The diamondback moth (DBM), Plutella xylostella (L.), is responsible for extensive losses in brassicas' production, with its control heavily relying on the use of insecticides. The imbricated brassica's leaves on the stem provide a suitable habitat for the ring-legged earwig, Euborellia annulipes (Lucas), to attack DBM larvae and pupae. The study focused on the combination of the earwig with indoxacarb and cyantraniliprole against DBM, as these insecticides target chewing and sucking sap pests infesting Brassica crops, respectively. These insecticides were tested against adult earwigs, 5th instar nymphs and predation upon DBM. When exposed to the recommended rates, the survival rates for nymphs were 74%, 100% and 96% in the cyantraniliprole, indoxacarb and control groups, respectively, and over 90% for adults. When 5th instar earwig nymphs were exposed to cyantraniliprole, they took 16.3 days to develop compared to indoxacarb (3.4 days) or the control group (3.2 days). Furthermore, females exposed to cyantraniliprole required more time to initiate oviposition and produced fewer eggs in the first egg batch. Despite that, the egg-hatching rate was greater than 80% in all treatments. Female earwigs confined to indoxacarb- or cyantraniliprole-treated or untreated leaves and DBM larvae maintained similar survival but lower consumption of DBM larvae when exposed to cyantraniliprole. The findings revealed that cyantraniliprole weakened the potential of the ring-legged earwig to control DBM. On the other hand, indoxacarb was harmless to the earwig and showed additive mortality for the pest. Therefore, indoxacarb seems compatible with E. annulipes, while cyantraniliprole has a sublethal effect that slows down development and reproduction.

Knowledge about cold tolerance of non-native biological control agents is critical to avoid permanently establishing them in new temperate areas outside of their native range. The cold tolerance of the predatory mites, Amblydromalus limonicus and Iphiseius degenerans, was investigated in the laboratory to assess their establishment potential in northern Europe, particularly Sweden. The lethal time of I. degenerans (the number of days until 100% mortality was reached) declined steeply from 5°C to 0°C and was almost zero at −5°C. The lethal time of A. limonicus did not differ between 5°C and 0°C, but was reduced at −5°C. For both species, LTime₅₀ (the number of days until 50% of the mites died) was longer for fed than for unfed mites. The lethal temperature of A. limonicus (the temperature at which 100% mortality was reached) was −17.75°C, whereas most I. degenerans died at −8.5°C. LTemp₅₀ (the temperature at which 50% of the mites died) was lower for A. limonicus (−9.8°C) than for I. degenerans (−0.1°C). Collectively, these findings suggest that I. degenerans is unlikely to establish in Sweden but that A. limonicus is more cold tolerant. This highlights the risk associated with releasing A. limonicus in Sweden due to concerns about potential establishment.

Diapause is a vital survival strategy for insects, enabling them to conserve energy and endure adverse conditions. Understanding how diapause affects insect phenology and population dynamics is crucial for the effective management of insect pests. Predictive pest phenological models can be invaluable tools for providing essential information to support management strategies. This study presents a modelling framework to incorporate diapause into phenological models when biological information on variables regulating and functions describing diapause induction and termination are lacking or limited. In our framework, insect phenology is divided into a set of phases characterized by specific events (diapause induction and termination) and processes (development of diapausing and post-diapausing biological stages). The phenology is simulated by a stage-structured model based on the Kolmogorov equation, and the temperature-dependent development rate functions are described by the Brière functional form. Our modelling framework was tested on a case study involving the prediction of the phenology of the codling moth, (Cydia pomonella L. 1758). Model calibration and validation were performed using four time-series adult trap catch data collected in the Emilia Romagna Region from 2021 to 2023. The calibration procedure allowed obtaining realistic parameters related to the temperature threshold triggering diapause termination and the development rate function of post-diapausing larvae and pupae. Model validation proved successful in simulating both the initial emergence and the overall phenological patterns of adults across the three observed generations. The methodological framework proposed here aims to facilitate the introduction of diapause in phenological models improving also their predictive abilities. The model may serve as an accurate and knowledge-based tool for planning and implementing pest monitoring and control actions based on the realistic predictions provided by the model on the phenological status of the pest.

Studies of oriental fruit moth (OFM), Grapholita molesta (Busck), and codling moth (CM), Cydia pomonella (L.) (Lepidoptera: Tortricidae), both important pests of pome fruit, evaluated the addition of low-intensity light-emitting diode (LED) to delta traps baited with 3 commercial monitoring lures. Studies were conducted in 9 orchards treated with and without sex pheromone mating disruption for one or both species. OFM was monitored with a two-part pheromone/kairomone lure (OFM Combo Dual), while CM was monitored with either a two-part kairomone lure (CM Dual 4 K) or a sex pheromone lure (CM PH). Both pests were monitored with or without the addition of three types of a low power LED light with peak intensity at 395 (UV-A), 458 (blue), and 516 (green) nm. The UV-A LED was found to be the most effective among the three lights for OFM. Unexpectedly, traps with the OFM Combo Dual lure plus UV-A LED caught similar numbers of CM as traps baited with the CM Dual 4 K and CM PH lures alone. They also caught other pest species, such as oblique banded leafroller (OBLR), Choristoneura rosaceana (Harris), and peach twig borer (PTB), Anarsia lineatella (Zeller). Interestingly, in different trials the OFM Combo Dual combined with UV-A LED light caught significantly more OFM and/or CM females compared to the OFM Combo Dual lure without light, opening the perspective for a female-oriented monitoring and for a “female removal” management approach of these pests. The development of inexpensive, dual-modality traps adding a light stimulus to a pheromone/kairomone lure may reduce monitoring costs in orchards with multiple moth pests, improving the trapping efficiency.

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.