Search Results (14)

To address the problems of high digging resistance, elevated energy consumption, and severe soil adhesion encountered during mechanized potato harvesting, a bionic potato digging shovel inspired by the corrugated dorsal structure of the white grub was developed. Based on reverse-engineered geometric curves, two longitudinally corrugated shovel models (L-S-1 and L-S-2) were constructed, and a coupled soil–potato–shovel model was established using the Discrete Element Method (DEM) to evaluate soil disturbance characteristics and digging resistance at a forward speed of 0.5 m/s and an entry angle of 35°. The simulation results indicated that the longitudinally corrugated shovel L-S-2 exhibited the best overall performance, reducing digging resistance by 13.87% and increasing the soil fragmentation rate by 20.67% compared with a conventional flat shovel (P-S). Using L-S-2 as the baseline design, additional DEM simulations were conducted at forward speeds ranging from 0.4 to 0.6 m/s to systematically investigate the influence of operating speed on digging performance. To further enhance anti-adhesion performance, a composite bionic shovel (H-L-S-2) was developed by embedding polytetrafluoroethylene (PTFE) hydrophobic material into the surface of L-S-2 and reinforcing the shovel tip using laser cladding. Soil-bin experiments were then performed under controlled conditions with forward speeds of 0.4–0.6 m/s and soil moisture contents of 15–20% at an entry angle of 35°, and the results showed an average resistance reduction rate of 17.46%, with a maximum reduction of 18.02%. Both DEM simulations and soil-bin tests confirmed the effectiveness of the composite bionic shovel in reducing soil adhesion, with the number of adhered soil particles decreasing by 41.2% in simulations and the mass of adhered soil reduced by 37.5% in physical tests. These results demonstrate that coupling a bionic corrugated structure with surface material modification can effectively reduce digging resistance, enhance soil fragmentation, and mitigate soil adhesion, providing a practical approach for optimizing the design of potato digging shovels. Full article

Eucalyptus plantations have suffered severe damage from scarab grubs in recent years. To investigate the actual scarab species that damage Eucalyptus trees, continuous closed-net monitoring and monthly soil-digging surveys were conducted in Eucalyptus plantations in Lancang County, China, from 2024 to 2025. The primarily affected roots were covered with nylon mesh bags until the insects reached adulthood. A few adults were successfully collected from the damaged roots. The scarab species that infests Eucalyptus trees has been identified as Megistophylla grandicornis (Fairmaire, 1891). It exhibited a single generation annually in local Eucalyptus plantations. Adults emerge from late April to June, and larvae cause damage from July to November. Eucalyptus trees with severely damaged roots exhibit reduced growth vigor and are highly prone to windthrow and death, leading to substantial losses in forestry production. These preliminary results provide foundational data for recognizing Megistophylla grandicornis as a new root pest of Eucalyptus and establishing targeted larval-monitoring protocols in Eucalyptus plantations. Full article

White grubs possess natural defense mechanisms against entomopathogenic nematodes (EPNs). Hence, EPN isolates that naturally infect white grubs tend to be among the most effective biological control agents of white grubs. We tested the virulence of four EPN isolates recently isolated from infected white grubs in turfgrass areas in central New Jersey, USA against third-instar larvae of Anomala orientalis, Popillia japonica, and Cyclocephala borealis, which are pests of turfgrass and ornamental plants in the northeastern USA. Against A. orientalis and P. japonica larvae, the Steinernema scarabaei Ad and S. scarabaei SL isolates were highly virulent in laboratory tests, whereas S. cubanum HF was less virulent and S. glaseri SH the least virulent. None of the isolates caused high mortality of C. borealis larvae. EPN efficacy in greenhouse tests against A. orientalis followed the same pattern. The original isolate of S. scarabaei, the AMK001 strain, that had been maintained in the laboratory on A. orientalis and P. japonica larvae for 19 years showed the same virulence level against A. orientalis larvae as it did soon after its first isolation and was also as virulent as the fresh S. scarabaei Ad isolate; both isolates were more virulent than S. scarabaei SL. Future tests should determine the ability of these white grub-adapted isolates to provide long-term suppression of white grub populations. Full article

Olfaction and gustation processes play key roles in the life cycle of insects, such as finding and accepting food sources, oviposition sites, and mates, among other fundamental aspects of insect development. In this context, chemosensory genes found in sensory organs (e.g., antennae and maxillary palps) are crucial for understanding insect behaviour, particularly the phytophagous behaviour of insect pests that attack economically important crops. An example is the scarab beetle Hylamorpha elegans, which feeds on the roots of several crops important for livestock in its larval stage. In this study, chemosensory gene candidates of H. elegans white grubs identified through the head transcriptome and phylogenetic and tissue-biased gene expression (antennae, head without antennae, and legs) have been reported. Overall, 47 chemosensory genes were identified (2 ORs, 1 GR, 11 IRs, 9 CSPs, and 24 OBPs). Gene expression analysis revealed the predominant presence of IRs in the legs, whereas ORs and the GR were present in the heads and/or antennae. Particularly, HeleOBP9 and HeleCSP2 were significantly expressed in the head but not in the antennae or legs; these and other genes are discussed as potential targets in the context of H. elegans management. Full article

The levels of different nutraceutical metabolites present in the jicama root were measured when subjecting the plant to induced biotic stress via infestation with Phyllophaga spp. (white grubs). The change in secondary metabolites on the stressed jicama roots (SJ), mostly antioxidants, was followed over 100, 140, and 180 days and compared against the non-infested control jicama (CJ). Our results show that infested (SJ) samples contained higher concentrations of tannins, flavonoids, and total phenols, measured using spectrophotometric methods, peaking at 140 days, and higher overall concentration of saponins. SJ samples showed higher DPPH inhibition, peaking at 100 days. Chlorogenic acid had the highest concentration among the phenolic compounds (7.47 mg g⁻¹), followed by protocatechuic acid, both in SJ, which was possibly related to the lower observed concentrations of caffeic and ferulic acids. As for flavonoids, we observed a high concentration of rutin in CJ and a low concentration of pelargonidin and myricetin in SJ, possibly promoted via the dihydrokaempferol pathway. Taken together, these results show that Phyllophaga spp.-mediated biotic stress affects the concentrations of secondary metabolites in the different maturity stages in jicama, having an effect on its metabolic pathways, which presents an opportunity for the use of material such as agro-industrial waste. Full article

The economic return for peanut (Arachis hypogaea L.) in Ghana is often low due to limitations in the availability of inputs or their adoption, which are needed to optimize yield. Six experiments were conducted in Ghana in 2020 and 2021 to determine the impact of planting date, cultivar, fertilization, pest management practices, and harvest date on peanut yield, financial return, and pest reaction. A wide range of interactions among these treatment factors were often observed for infestations of aphids (Aphis gossypii Glover); groundnut rosette disease (Umbravirus: Tombusviridaee); millipedes (Peridontopyge spp.); white grubs (Schyzonicha spp.); wireworms (Conoderus spp.); termites (Microtermes and Odontotermes spp.); canopy defoliation as a result of early leaf spot disease caused by Passalora arachidicola (Hori) and late leaf spot caused by Nothopassalora personata (Berk. and M. A. Curtis); and the scarification and boring of pods caused by arthropod feeding. Pod yield and economic return increased for the cultivar Chitaochi and Sarinut 2 when fertilizer was applied and when fertilizer was applied at early, mid-, and late planting dates. Pod yield and economic return increased when a combination of locally derived potassium soaps was used for aphid suppression and one additional hand weeding was used in the improved pest management practice compared with the traditional practice without these inputs. Pearson correlations for yield and economic return were negatively correlated for all pests and damage caused by pests. The results from these experiments can be used by farmers and their advisors to develop production packages for peanut production in Ghana. Full article

The genus Metarhizium is one of the most significant entomopathogenic fungi with diverse morphological characteristics and host species. Species of Metarhizium have been widely used for pest control as an environmentally safe alternative to chemical pesticides. This study reports a new species of Metarhizium and a new record of M. bibionidarum from China. The taxonomic positions of the two species within Metarhizium were assessed by morphological and multi-gene phylogenetic data. This assessment confirmed that the new species M. dianzhongense on white grubs (Coleoptera) is a sister to M. ellipsoideum on adult leafhoppers (Hemiptera) and represents a distinctive fungus according to the morphological and phylogenetic evidence. The two species, M. dianzhongense and M. bibionidarum, were described and illustrated. Pathogenicity tests by M. bibionidarum and M. dianzhongense were performed on early instar larvae of the significant agricultural pest Spodoptera frugipera (Lepidoptera). The results demonstrated that both M. bibionidarum and M. dianzhongense exhibit significant insecticidal activity against larvae of S. frugipera, providing new fungal resources for the development of an eco-friendly biocontrol agent against this pest. Full article

Injury and control costs for the invasive scarab Japanese beetle (Family Scarabeidae, Popillla japonica) alone is estimated at $450 million per year in the U.S. Chemical controls are commonly used to control scarab pests, but concerns about human safety and negative impacts on beneficial and non-target organisms, such as pollinators, are increasingly driving the market towards less toxic and more environmentally friendly management options. Microbial entomopathogens are excellent candidates for biopesticides and biocontrol agents. Although microbial pesticides currently make up only 1–2% of the insecticide market, the discovery and development of new microbes are increasing. Microbial products are non-toxic to humans and most are species-specific, reducing non-target effects. While some are slow-acting, others provide rapid control and some can be as efficacious as chemical insecticides, particularly when used in combination. Another major advantage of microbial controls is that many can persist in the environment, and become biocontrol agents, providing long-term control and reducing costs. This article provides a summary of the microbial entomopathogens that are known to infect scarab beetle species including bacterial, fungal, viral, microsporidian, and protozoan taxa, as well as the existing formulations and their efficacy. Lesser-known microbial species are also discussed as potential future controls. We also discuss the development of new techniques for improving efficacy, such as genetic engineering, synergistic interactions, auto-dissemination strategies, and improved formulations. Full article

The runoff or leaching of nitrogen fertilizers from monoculture turfgrass lawns contri-butes to water pollution, and such lawns are susceptible to insect pests and provide few resources for pollinators. One approach to creating more sustainable lawns is to incorporate white clover (Trifolium repens L.), a nitrogen-fixing legume, into grass seed mixtures or existing turfgrass swards. “Dutch” white clover (DWC), a ubiquitous landrace, forms non-uniform clumps when intermixed with turfgrasses, thus it is often considered to be a lawn weed. Recently, several dwarf varieties of white clover have been selected for their small leaf size and low growth habit, allowing them to tolerate low mowing heights and blend better with grasses. To date, there have been no studies published on the entomological aspects of dwarf clover in pure stands or intermixed with turfgrass. We established field plots with combinations of DWC, two cultivars of dwarf clover, and tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) in monoculture or mixed swards, and compared the invertebrate communities therein. Predatory arthropods and earthworm numbers were similar in all plot types. The clover monocultures were resistant to white grubs, but the grub densities in the clover–tall fescue dicultures were similar to those found in the pure tall fescue swards. Dwarf clovers and DWC were similarly attractive to bees and supported similar bee assemblages. The tall fescue foliar N content was elevated 17–27% in the dicultures with clovers. Full article

Serratia marcescens is a Gram negative bacterium (Enterobacteriaceae) often associated with infection of insects. In order to find pathogenic bacteria with the potential to control scarab larvae, several bacterial strains were isolated from the hemocoel of diseased Phyllophaga spp (Coleoptera:Scarabaeidae) larvae collected from cornfields in Mexico. Five isolates were identified as Serratia marcescens by 16S rRNA gene sequencing and biochemical tests. Oral and injection bioassays using healthy Phyllophaga blanchardi larvae fed with the S. marcescens isolates showed different degrees of antifeeding effect and mortality. No insecticidal activity was observed for Spodoptera frugiperda larvae (Lepidoptera: Noctuidae) by oral inoculation. S. marcescens (Sm81) cell-free culture supernatant caused significant antifeeding effect and mortality to P. blanchardi larvae by oral bioassay and also mortality by injection bioassay. Heat treated culture broths lost the ability to cause disease symptoms, suggesting the involvement of proteins in the toxic activity. A protein of 50.2 kDa was purified from the cell-free broth and showed insecticidal activity by injection bioassay towards P. blanchardi. Analysis of the insecticidal protein by tandem- mass spectrometry (LC-MS/MS) showed similarity to a Serralysin-like protein from S. marcescens spp. This insecticidal protein could have applications in agricultural biotechnology. Full article

The authors made two visits to the Juba Sugar Project in south-west Somalia, at the beginning of the minor rains in October 1986, and at the beginning of the main rains in March 1987. Observations were made on morphospecies of scarabaeid white grub larvae, the adults, and the two associated for the key economic species, Cochliotis melolonthoides and Brachylepis werneri. Sampling larvae and adults by digging soil quadrats and adults by light trapping gave useful information on their biology and phenology. Sampling methods were evaluated and economic thresholds were extrapolated based on earlier work. Natural enemies were surveyed, and entomopathogenic nematodes and a cordyceps fungus (Ophiocordyceps barnesii) were considered to have potential to be used as biological control interventions. Full article

White grubs are larvae of Coleoptera of the family Scarabaeidae. They are known because of their intensive feeding habits on crop roots. Mallophora ruficauda (Diptera: Asilidae) is a dipteran parasitoid whose larva is a natural enemy for white grubs. This species is a solitary ectoparasitoid, where both female and larva realize different steps in the host location process. Female place its eggs in high grasslands and then, the larva finds and parasitizes the host in the ground. There are nine potential hosts in the area of action of this parasitoid; however a high preference for Cyclocephala signaticollis has been observed (87% of field parasitism). It is known that many insects have developed defensive and immunological mechanisms when attacked by a parasitoid, which can be behavioral, physiological, chemical or genetic. The objectives of this work were to investigate what kind of defense and non-immunological associated mechanisms the white grubs have against this parasitoid and to understand why M. ruficauda have such a high preference for masked chafer grubs or Cyclocephala species. In particular, for each white grub species, we asked: (1) If there is a differential behavioral reaction when a parasitoid attack is simulated; (2) If body attributes of white grubs species have influence on defense behavior, and particularly for the masked chafer C. signaticollis; and (3) Why this species is the most selected by M. ruficauda. It was found that behavioral defenses of white grubs would explain the parasitism pattern of M. ruficauda larvae and its preference for C. signaticollis. Full article

We determined virulence of seven Heterorhabditis bacteriophora strain GPS11 inbred lines possessing superior infective juvenile longevity, and heat and ultra violet radiation tolerance against white grubs Popillia japonica and Cyclocephala borealis. At 1 and 2 weeks after treatment, inbred line A2 was significantly more virulent towards P. japonica compared to the parent strain GPS11 and inbred lines A7, A8, A12 and A21; and line A2 caused significantly higher C. borealis mortality than lines A6 and A12. Penetration, encapsulation and survival of two inbred lines, A2 and A12, that showed the highest and lowest virulence against both grub species were then assessed. There were no differences between the two lines for the total number of nematodes penetrated in either P. japonica or C. borealis within the first 24 h, but a significantly higher percentage of penetrated nematodes were alive in line A2 compared to the line A12 in both grub species. P. japonica immune response over time to hemocoel-injected nematodes of A2, A12 and the parent strain was further investigated. While all injected nematodes were encapsulated at 6 h post injection, non-encapsulated living nematodes were detected at 12 and 24 h post injection, showing the breakage out of encapsulation. A higher percentage of non-encapsulated living nematodes and a lower percentage of dead nematodes were found in line A2 as compared to the line A12 after 12 h post injection. These data suggest that virulence differences in the studied H. bacteriophora inbred lines are not due to differences in nematode penetration or recognition by the grub immune system, but are related to the ability of the infective juveniles to break out of encapsulation. Full article

In this study, 207 strains of aerobic and facultatively anaerobic cellulolytic bacteria were isolated from the gut of Holotrichia parallela larvae. These bacterial isolates were assigned to 21 genotypes by amplified ribosomal DNA restriction analysis (ARDRA). A partial 16S rDNA sequence analysis and standard biochemical and physiological tests were used for the assignment of the 21 representative isolates. Our results show that the cellulolytic bacterial community is dominated by the Proteobacteria (70.05%), followed by the Actinobacteria (24.15%), the Firmicutes (4.35%), and the Bacteroidetes (1.45%). At the genus level, Gram-negative bacteria including Pseudomonas, Ochrobactrum, Rhizobium, Cellulosimicrobium, and Microbacterium were the predominant groups, but members of Bacillus, Dyadobacter, Siphonobacter, Paracoccus, Kaistia, Devosia, Labrys, Ensifer, Variovorax, Shinella, Citrobacter, and Stenotrophomonas were also found. Furthermore, our results suggest that a significant amount of bacterial diversity exists among the cellulolytic bacteria, and that Siphonobacter aquaeclarae, Cellulosimicrobium funkei, Paracoccus sulfuroxidans, Ochrobactrum cytisi, Ochrobactrum haematophilum, Kaistia adipata, Devosia riboflavina, Labrys neptuniae, Ensifer adhaerens, Shinella zoogloeoides, Citrobacter freundii, and Pseudomonas nitroreducens are reported to be cellulolytic for the first time in this study. Our results indicate that the scarab gut is an attractive source for the study of novel cellulolytic microorganisms and enzymes useful for cellulose degradation. Full article