Journal of Pest Science最新文献

Insects are vital arthropods that significantly impact various ecosystems. Their successful colonization of diverse habitats spanning from cold to warm environments is made possible by numerous adaptations shaped by environmental selection. This comprehensive review delves into the spectrum of physiological adaptations exhibited by insects to thrive in diverse environments, with a particular emphasis on the connection between these adaptations and the challenges posed by cold temperatures. Focusing on both long-term and short-term strategies, the review highlights the key protective mechanisms that insects employ to cope and thrive in cold temperatures. To withstand these constraints, insects have developed four main strategies: freeze tolerance, freeze avoidance, cryoprotective dehydration, and vitrification. These adaptive responses involve crucial physiological and biochemical changes that enable insects to withstand low temperatures. Specifically, insects exhibit cold tolerance through a range of molecular adaptive strategies, which encompass alterations in the expression of specific target genes, the synthesis of ice core formers, and the production of polyol cryoprotectants. Despite these remarkable results, there is still a lack of in-depth knowledge about the major factors contributing to successful overwintering of insects and their ability to withstand extremely low temperatures. To address these gaps, technological advances and genome sequencing of model organisms are critical to uncover the molecular mechanisms in insect responses to low temperatures. The knowledge gained from these advances provides valuable information about insect cold tolerance strategies and paves the way for a better understanding of their ecological importance and potential applications in conservation and ecological management.

Cotesia ruficrus (Hymenoptera: Braconidae) is an endoparasitic natural enemy of various Lepidopteran pests, and it plays a significant role in integrated pest management. In the field survey of maize fields, we found for the first time that the indigenous parasitoid C. ruficrus parasitized the major invasive pest Spodoptera frugiperda (Lepidoptera: Noctuidae) in China. We identified 18 odorant-binding proteins (CrufOBPs) of C. ruficrus through the RNA-Seq method, and PCR analysis showed that 13 out of the CrufOBPs were highly expressed in antennae. Two CrufOBPs, CrufOBP3 with the highest antennal expression and CrufOBP17 with antenna-specific expression, were selected for protein biosynthesis in the prokaryotic protein expression system and subjected to protein purification. Through fluorescence binding assay, seven maize volatile compounds were selected for the antennal electroantennography (EAG) study, and the results indicated that female C. ruficrus exhibited distinct responses to these volatiles at different concentrations. Octanal and 2-heptanone of 10 mg mL⁻¹ were chosen for olfactory behavioral experiments because of their high EAG responses, and the results showed that C. ruficrus adults were significantly attracted at certain concentrations. Furthermore, in the cage experiments, 10 mg mL⁻¹ of 2-heptanone significantly increased the parasitism rate of C. ruficrus on S. frugiperda. These findings not only provide a theoretical basis for studying the odorant-binding protein family of C. ruficrus but also contribute to the development of novel pest control strategies for this invasive pest management.

The red-necked longhorn beetle, Aromia bungii (Coleoptera: Cerambycidae), is a wood-boring pest of ornamental cherry trees in the Rosaceae family. This study evaluates the effectiveness of a preventive measure using fine-mesh netting in preventing A. bungii from oviposition on host cherry trees. Aromia bungii typically oviposits in cracks and crevices of host tree bark using its elongated ovipositor, leading to higher infestations on the lower trunk where there are abundant rough barks suitable for the beetle oviposition. Therefore, we assessed the effectiveness of netting with a gap that exceeded the reach of the A. bungii ovipositor from the tree surface. This evaluation involved laboratory experiments using cut branches and field experiments using lower trunks from standing trees. In the field, we determined the distribution of A. bungii body sizes and estimated the maximum ovipositor length based on their proportional relationship. This led to the establishment of a 10 mm gap for the test net, featuring a 0.4 mm mesh. Both laboratory and field experiments confirmed that the 0.4 mm mesh net with the specified gap effectively prevented A. bungii oviposition in netted areas. Field experiments also suggested a potential shift in oviposition sites from netted (lower) to un-netted (upper) areas in trees with nets, considering results from trees without nets. Although various measures, such as insecticide spraying, are necessary to safeguard areas without nets, our netting method can serve as a fundamental component of integrated pest management against A. bungii.

A dynamic homeostasis between gut microbiome and the host is essential for animals. Antibiotics feeding may be a good way to study the function of microbes in insects due to efficiency and a linkage with pest control. Here, by using 16S rDNA sequencing, we show antibiotics feeding significantly altered the composition and diversity of microbes in different stages of Spodoptera frugiperda and showed dose dependent effects. Antibiotics ingestion resulted in a dramatic reduction of Enterococcus in larvae and Klebsiella in adults, but increase of Weissella in larvae and Pseudomonas in pupae and adults. Enterococcus spp in the lepidopteran gut may play a protective role against insect pathogens and Klebsiella spp may have positive effects on insect fecundity. Some strains from Pseudomonas and Weissella are pathogens or opportunistic pathogens. Further biological assay showed that antibiotics treatment significantly affected the fitness of treated insects and their untreated offspring, with treated insects and their offspring having longer developmental period but lower body weight, survival rate, flight capacity and fecundity than those of controls. Lepidopterans may rely on gut microbiome for some digestions and previous study indicated that antibiotics-induced dysbiosis of gut microbes affects many biological processes of S. frugiperda. Therefore, it is possible that antibiotics disrupted the homeostasis of gut microbes and the host, which then negatively affected the survival and reproduction of S. frugiperda. These findings contribute to a better understanding of the role of the microbiota in insects and will aid in the development of environmentally friendly management techniques for this pest.

The spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is a serious pest in vineyards where it is difficult to control. Trap cropping, which involves manipulating the host plant composition in the crop vicinity to lure the pest away from grapes and towards more attractive host plant fruits, might be an interesting but so far neglected control approach to limit SWD egg-laying in grapes. An ideal trap crop should be more attractive to the pest than the actual crop and should ideally restrict pest development. We determined the attractiveness of fruits of 60 plant species for SWD egg-laying and their suitability for larval development in laboratory assays. Compared to grapes, 16 of the 60 fruits were strongly preferred by SWD females for egg-laying and additionally inhibited the development of SWD larvae into adults. Host preference was strongly influenced by the hardness of the fruit skin, and larval development was marginally affected by the acidity of fruits. However, none of the measured fruit traits had a significant effect on the emergence success of SWD. All 16 candidate trap crop plants should be further tested for their potential to reduce SWD infestation of grapes. We provide practical advice on the next steps to be taken for implementing a successful trap cropping strategy against SWD in commercial vineyards.

Abstract

Blue sticky traps contribute substantially to monitoring the western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), in greenhouses. Although sticky traps can detect the initial presence of thrips reliably, an estimation of the actual thrips density in the crop by counting number of thrips on the traps is often not accurate. To overcome this issue, we compared blue sticky traps and newly developed sticky LED-enlightened traps in combination with the commercial thrips kairomone Lurem-TR under commercial growing conditions. Therefore, an experiment was conducted in cucumber, Cucumis sativus L. (Cucurbitaceae), crop stands in greenhouse cabins investigating the correlation between thrips caught on (LED) traps and the thrips density in the crop for an accurate and reliable thrips monitoring. Additionally, experiments aiming to understand underlying mechanisms of thrips orientation towards traps in different scenarios were conducted under controlled conditions. Results show that thrips catches on sticky LED enlightened coloured traps correlated strongly positive with number of thrips in the crop, especially at low thrips population densities. Adding Lurem to this trap type further improved accuracy of the correlation in the greenhouse cabin experiment. Moreover, LED traps with and without Lurem were more attractive towards thrips in small follow-up experiments compared to standard blue sticky traps. The results are discussed in the context of general orientation of thrips and its behaviour towards visual and olfactory cues when considering different scenarios. Our study shows the successful integration of blue LEDs into an existing trapping system and underlines the advantages compared with standard sticky plates. In conclusion, sticky LED enlightened coloured traps have a potential as an improved thrips monitoring device that might improve pest management decisions.

Cotton aphids (Aphis gossypii Glover) are important pests of cucurbit crops. Plant defenses at different cell layers, including the leaf surface, mesophyll cells, and phloem, are employed to defend aphids. Here, we assessed differences in aphid resistance among six watermelon varieties and elucidated the defense mechanisms underlying aphid-resistant/susceptible watermelon varieties. The population abundance, offspring number per female, and meantime of phloem-feeding (E2 phase) of aphids were the highest on XiNong (XN), followed by JingXin (JX), TianWang (TW), ZaoJia (ZJ), and MeiFuLai (MFL), and these parameters were the lowest on JinMeiDu (JMD). Further analyses showed that there was no correlation between the aphid resistance of six watermelon varieties and defenses at the leaf surface. For defenses at mesophyll cells, aphid infestation increased salicylic acid (SA) content at 48 h post-infestation (hpi) and ROS accumulation at 6 and 12 hpi in six watermelon varieties. For phloem defenses, aphid infestation increased callose content in JMD plants but decreased callose content in JX, TW, ZJ, MFL, and XN plants at 6, 12, 24, and 48 hpi. Moreover, callose deposition suppressed by 2-deoxy-d-glucose (2-DDG) neutralized the resistance of JMD plants and exacerbated the susceptibility of XN plants to aphids, which exhibited a higher population abundance and E2 phase time. Collectively, phloem defenses regulated by aphid-induced callose deposition were responsible for differences in aphid resistance among the watermelon varieties.

Root-knot nematodes (Meloidogyne spp.) are highly destructive pests that cause enormous crop losses worldwide. With the increasing awareness of environmental protection, exploring the potential of biocontrol agents has become crucial for nematode management. Priestia megaterium YB-3 was originally isolated from rice rhizosphere soil. In vitro experiments with the fermentation supernatant of YB-3 exhibited up to 96.0% mortality of M. graminicola second-stage juveniles (J2) and 39.2% egg hatching inhibition rate at 48 h after treatment. In greenhouse and field experiments, the application of YB-3 significantly suppressed the gall index, final nematode and egg populations compared to the untreated control, while it promoted rice (Oryza sativa) growth. YB-3 showed consistently high biocontrol efficacy against M. graminicola. Moreover, YB-3 remarkably enhanced the expression of defence genes involved in salicylic acid (OsNPR1, OsWRKY45, OsPR1a), jasmonic acid (OsJaMYB, OsAOS2) and ethylene (OsACS1) signalling pathways at different levels. In addition, YB-3 steadily colonized rice rhizosphere soil at levels ranging from 3.54 × 10³ to 9.08 × 10⁴ cfu/g soil. High-throughput sequencing analysis showed that the application of YB-3 had no significant influence on the rice rhizosphere microbial community structure, and the taxa enriched in the YB-3 treatment were Acidobacteria, Bacteroidetes and Ascomycota. YB-3 effectively suppressed M. graminicola infection, possibly because it colonized the rice rhizosphere, induced plant resistance and increased the relative abundances of beneficial microorganisms. Priestia megaterium YB-3 could be a promising and safe biological component in the integrated management of M. graminicola.

Abstract

Zoophytophagous predators can induce plant defence responses through phytophagous feeding. Since the zoophytophagous bug Orius sauteri lays eggs into plant tissues, we hypothesised that its oviposition behaviour may also induce plant defence responses with a negative impact on subsequent herbivore attacks. Pre-inoculation of O. sauteri females on tomato plants significantly reduced the fitness and reproduction of Frankliniella occidentalis, which also preferred the non-inoculated plants in indoor micro-environments. In the field, O. sauteri pre-inoculation also caused reduced population growth of F. occidentalis. All these tendencies were weaker with male compared to female O. sauteri pre-inoculation. Next, a transcriptome analysis showed that the MAPK signalling pathway, the plant hormone signal transduction and plant-pathogen interaction of defence-related pathways were significantly enriched in plants inoculated with O. sauteri females compared to untreated plants. We showed that three key genes of the JA pathway, allene oxide synthase (AOS), jasmonate ZIM-domain 2 (JAZ2), and proteinase inhibitor 1 (PI-1), were upregulated. This is evidence of plant defence activation, the likely mechanism by which O. sauteri pre-inoculation (through feeding and oviposition activities) reduced F. occidentalis fitness in the laboratory and population densities by almost three times in a greenhouse experiment. This mechanism could be promoted in IPM strategies through the early introduction of zoophytophagous biocontrol agents activating crop plant defences to enhance biological pest control.

Myzus persicae and Aphis gossypii (Hemiptera: Aphididae) are two of the most significant aphid species acting as vectors for plant viruses in vegetable crops worldwide. This work provides new knowledge relating the persistence (including population growth and survival) and impact on aphid probing and feeding behaviour of plant essential oil-derived products. Modifications in M. persicae behaviour (EPG results) were noted in plants treated with 0.2% nanoemulsions of distilled lemon oil: (1) the non-probing activity lasted longer, (2) both non-phloematic probing and phloem ingestion activities of aphids were shorter, and (3) xylem ingestion activity and the time taken to achieve sustained phloem ingestion appear to be longer. Finally, a slight increase was also observed in the mean duration of the non-probing activity of M. persicae on plants treated with 0.2% nanoemulsions of farnesol. When pepper plants were sprayed with a 0.2% nanoemulsion of farnesol with Tween 80^® (1:2), the population growth of M. persicae colonies on treated plants was slower (40 aphids/plant) than on controls (60 aphids/plant) up to the day seven. The slope of the aphid population growth line corresponding to the formulated mixture of bioactive volatiles was lower (2.26 b) and statistically significant in comparison with the control (7.09 a), probably due to a controlled-release effect up to day 14. No systemic effects were obtained for the bioactive volatiles tested.