Neotropical Entomology最新文献

This study evaluated the larvicidal efficacy of the methanol extract of Dactyloctenium aegyptium against Aedes aegypti (L, 1762) (Diptera: Culicidae), Anopheles stephensi Liston, 1901 (Diptera: Culicidae), and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae). The methanol extract exhibited the highest mortality rates, achieving 100% mortality at 250 µg/mL for all species tested, and demonstrated the lowest LC₅₀ values of 94.28 µg/mL for Ae. aegypti, 119.07 µg/mL for An. stephensi, and 103.71 µg/mL for Cx. quinquefasciatus. In contrast, the n-hexane extract was the least effective against Ae. aegypti and Cx. quinquefasciatus, while the chloroform extract showed the least efficacy against An. stephensi. Statistical analysis confirmed the significant impact of extract concentration, type, and mosquito species on mortality rates, with the model explaining 98.4% of the variance. GC-MS analysis of the methanol extract identified several bioactive compounds, with stigmasterol being the most abundant (13.92%), followed by gamma-sitosterol (10.40%) and campesterol (5.31%). Molecular docking studies revealed that campesterol exhibited the highest binding affinity with docking scores of -9.6 kcal/mol for the sterol carrier protein from Ae. aegypti (PDB ID: 1PZ4) and -10.3 kcal/mol for acetylcholinesterase from Anopheles gambiae (PDB ID: 5X61). Additionally, stigmasterol and sitosterol showed significant binding affinities of -9.4 and -9.0 kcal/mol against 1PZ4, and -9.5 and -9.4 kcal/mol against 5X61, respectively. Citrost-7-en-3-ol demonstrated a promising affinity of -9.7 kcal/mol for acetylcholinesterase. Overall, the methanol extract of D. aegyptium shows promise for mosquito control, with specific compounds identified as potential inhibitors of key targets in vector control strategies.

The corn leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae) and its associated corn diseases are considered the main production drawback currently faced by maize growers across South America, especially in Brazil. Native to Mexico and historically restricted to tropical America, the species has recently increased its occurrence in temperate areas of the continent, raising the need for a deeper understanding of the genetic basis driving its population dynamics. In this study, we used the partial mitochondrial DNA cytochrome c oxidase I (mtCOI) gene to characterize D. maidis collected in eight Brazilian sites and one Paraguayan site, as well as publicly available mtCOI data from Argentina and Mexico, to investigate genetic diversity and population structure of this important maize pest. Our results revealed low genetic diversity (π = 0.00162, Hd = 0.433) in the mtCOI partial gene region of the surveyed D. maidis populations. Six haplotypes were identified, with one potential ancestral (haplotype A) predominating in Mexico and tropical South America, and a second, possibly more recent one (haplotype B) standing out in temperate areas of the continent. The population structure detected indicates that outbreaks of D. maidis in different regions are associated primarily with local populations, with minor contribution from long-distance dispersal of insects, and limited gene flow across different countries and macro-regions. Based on these findings, pest management strategies should focus on suppressing winter survival and migration of D. maidis within a regional scale, thus reducing population pressure in maize crops.

Diaspis echinocacti (Bouché) (Hemiptera: Diaspididae) damages Opuntia spp. by feeding on the cladodes, reducing photosynthesis and causing economic losses. This study explored an integrated pest management approach to control D. echinocacti, using a combination of parasitoids species [ectoparasitoid Aphytis debachi Azim (Hymenoptera: Aphelinidae) and endoparasitoid Plagiomerus diaspidis Crawford (Hymenoptera: Encyrtidae)] and entomopathogenic microorganisms (Alternaria murispora Ariyawansa and Hyde, Alternaria destruens (Simmons), and three different Streptomyces species: Streptomyces bellus Margalith and Beretta [strains E23-2 and E25-12], Streptomyces galilaeus (Ettlinger et al.), and Streptomyces africanus (Meyers et al.). Laboratory trials showed that A. murispora and A. destruens at 10¹⁰ conidia mL^-1 achieved the highest mortality rates (57.2% and 52.2%, respectively) after 14 days of application. Streptomyces species also proved effective, with S. bellus-E23-2 and S. galilaeus causing significant mortality (53.8% and 49.8%, respectively) at 10¹⁰ CFU mL^-1. Combining parasitoids with these entomopathogens yielded varied results, with a notable success in the pairing of P. diaspidis with A. murispora at 10¹⁰ conidia mL^-1 (89.7% mortality) and P. diaspidis with S. bellus-E23-2 at 10¹⁰ CFU mL^-1 (86.3%). These findings revealed a mix of antagonistic and additive interactions, emphasizing the complexity of combining these biological agents. Semi-field trials confirmed the laboratory results, with P. diaspidis + A. murispora at 10¹⁰ conidia mL^-1 achieving 50.4% mortality and P. diaspidis + A. destruens at 10¹⁰ conidia mL^-1 reaching 49.2% mortality after 14 days of application. Thus, the accurate mix of biological control agents can effectively contribute to D. echinocacti management, emphasizing the importance of considering their interactions.

The excessive use of synthetic chemical pesticides in agriculture has led to the emergence of resistant insect populations, posing significant threats to both ecosystems and human health. As part of sustainable pest management, Integrated Pest Management (IPM) strategies have increasingly incorporated eco-friendly alternatives, such as plant ethanolic extracts, to reduce chemical pesticide dependency. This study aimed to evaluate the effectiveness of ethanolic extracts from Cannabis sativa L., Citrullus colocynthis L. Schrad., and Laurus nobilis L. in controlling tomato crop pests. Repellency essays, olfactometer responses, and field trials were conducted to compare the efficacy of these extracts with natural enemies (ladybird beetle Coccinella septempunctata L. and zigzag beetle Menochilus sexmaculatus Fabricius) and a synthetic pesticide (Acetamiprid 20% SP). Results show that L. nobilis exhibited the highest repellency against whiteflies and thrips, significantly reducing pest population, followed by C. colocynthis and C. sativa. Olfactometer bioassays revealed that C. septempunctata and M. sexmaculatus were strongly attracted to L. nobilis and C. sativa. Greenhouse trials demonstrated that the combination of natural enemies and botanical extracts resulted in a significantly lower pest population compared to synthetic pesticides alone. These findings support the potential of botanical extracts, particularly L. nobilis, as integral components of IPM systems, offering an environmentally sustainable approach to pest management by reducing reliance on chemical pesticides while promoting crop health and productivity.

In agriculture, spontaneous field border vegetation offers numerous benefits, such as reducing soil erosion, enhancing carbon sequestration, conserving biodiversity, and supporting biological control. However, the extent of these benefits often depends on the contexts of location and time. As for biological control, field borders can promote natural enemy conservation if the plants therein can provide adequate resources (e.g. shelter, alternative food, microclimate). In the context of location, field borders can be adjacent to areas with varying degrees of agricultural intensification, including fields with annual crops, perennial crops, or forest areas. While many studies have investigated how field borders can influence arthropod communities in adjacent crops, the opposite direction of effect (i.e. how crop areas can influence adjacent field borders) remains an underexplored topic. Therefore, in this three-season study, we selected vegetated field borders next to annual crops, perennial crops, and forest areas, to study their communities of spontaneous plants and arthropods as well as their potential to engender biological control nearby. In general, our results indicate that both plant and arthropod community composition were influenced by the type of adjacent land use and season. Field border vegetation next to areas with higher level of agricultural intensification (i.e. annual or perennial crops) harbored more herbivores, flowers, and natural enemies, although some of these results were season dependent. Field borders adjacent to annual or perennial crop areas promoted stronger biological control of aphids, likely due to complementary food resources (herbivores and floral resources) provided for natural enemies by the plants within those borders. Taken altogether, our results reinforce the importance of preserving spontaneous field border vegetation, especially in areas under intensive agriculture management.

Annulata J. Hall is a recently described monotypic riodinid genus composed of a single myrmecophilous butterfly species, Annulata annulifera Godman, which occurs in bamboo forests in the Amazonian region. Here, we describe a new species of this genus, Annulata kaminskii Seraphim, Freitas & Mota sp. nov., from the southern Brazilian Amazonia, in addition to its life history and immature stages. This new species is aphytophagous and involved in a four-level trophic interaction with the bamboo plants it inhabits, scale insects whose honeydew and wax it feeds on, and two different, parabiotic ant species that tend to young and older larvae. This is the first case of a butterfly larva observed to offer, as rewards to tending ants, both a secretion produced by specific ant-organs (tentacle nectary organs) and an anal exudate that probably results from its liquid diet. Annulata kaminskii sp. nov. larvae present both tentacle nectary organs and vibratory papillae as ant-organs but anterior tentacle organs are absent. Furthermore, we provide a preliminary attempt at a phylogenetic hypothesis suggesting its systematic position within the Nymphidiini, as a member of the Lemoniadina subtribe (Nymphidiini: Riodininae), despite its lack of anterior tentacle organs. We further discuss the evolution of complex life-history traits in myrmecophilous butterflies in light of current published evidence.

Aphids (Hemiptera: Aphididae) are well-known agricultural pests, affecting global crop production both through direct feeding and as the vector of multiple plant viruses. The classification of citrus aphid species was outdated and limited within the Zhejiang Province, China. A comprehensive investigation was conducted to determine the aphid species associated with citrus cultivars from 2019 to 2024. The present study included an analysis of occurrence rate, ecological contexts, and microscope slides photographs of apterous viviparous female, along with the key morphometric parameters such as body length, antenna, rostrum, hind tarsus, cauda, and siphunculi. Our morphological and molecular data revealed five species in this particular citrus region. Among the identified species, Aphis (Aphis) gossypii Glover and A. (A.) spiraecola Patch were the most prevalent, followed by A. (A.) craccivora Koch, A. (Toxoptera) citricidus (Kirkaldy), and A. (T.) aurantii Boyer de Fonscolombe. Furthermore, the genetic variation among aphid clades was assessed using Kimura 2-parameter (K2P) model. The results showed that citrus aphid species exhibits low intraspecific genetic variation and high interspecific genetic variation. Although the morphometric parameters of these aphid species are relatively similar, they can be distinguished through extensive morphological characteristics and cytochrome c oxidase subunit I (COI) fragment. Additionally, this study also addresses the historical and current distinctions among A. (A.) spiraecola and A. (T.) citricidus. These findings will significantly contribute to the ongoing research and management of citrus aphids in citrus plantations.

Host plant resistance (HPR) is a fundamental control tactic in integrated pest management programs. The evaluation of plant varieties for the expression of resistance against major insect pests is a key step for recommending and deploying resistant varieties in crops where pest pressure is high. Therefore, the use and publicizing of appropriate terminologies on HPR have a pivotal role in conveying information on effective resistant varieties to the scientific community and farmers. Basically, there are two HPR terminologies being used in the Entomology scientific literature: the classical HPR definition based on the trichotomous model of resistance, i.e., antixenosis, antibiosis, and tolerance; and a more recent proposition dividing plant defense into resistance vs. tolerance, the sichotomous model, which also incorporates the concepts of constitutive vs. induced resistance and direct vs. indirect resistance. In addition, there is scarce information on insect-resistance levels in commercial plant varieties to be divulged in seed labels, with exception of the Bt transgenic varieties. Using unstandardized technical terms on HPR can be confusing and less likely to transmit proper information on resistant varieties, hindering their use in the field. This review discusses the terminologies on HPR, the research gaps, and proposes a concept of what should be considered a resistant variety for practical purposes and uses by farmers, extension services, and the scientific public. Finally, the proposed HPR defense-growth model is presented for appreciation.

The increasing demand for eco-friendly pest management solutions has sparked a renewed interest in botanical insecticides. These plant-based insecticides offer a more sustainable option compared to synthetic chemicals, minimizing harm to non-target organisms. Nevertheless, certain challenges like rapid degradation, low stability, and limited efficacy in field conditions have hindered their extensive adoption. This review thoroughly examines recent developments in formulations and delivery techniques with the goal of enhancing the effectiveness of botanical insecticides. In addition, we explore innovative methods such as nanoformulations, encapsulating technologies, and controlled release systems to improve the stability, bioavailability, and targeted delivery of these natural substances. Furthermore, the paper highlights the significance of synergists and adjuvants in enhancing the effectiveness of insecticides and addressing resistance issues in pest populations. Through a thorough analysis of existing research and the identification of important areas that need further exploration, this review seeks to offer valuable insights that can contribute to the creation of botanical insecticide products that are both more efficient and commercially successful. In addition, a comprehensive list of market products that utilize these innovative formulations is also included.

The productivity of eucalyptus is threatened by several pests, including the red gum lerp psyllid, Glycaspis brimblecombei, which causes significant losses in forest systems. In Brazil, the lacewings Ceraeochrysa cubana and Chrysoperla externa are common in eucalyptus plantations, but little is known about the behavior of these predators toward the red gum lerp psyllid. This study evaluated the predatory behavior of larvae of both lacewing species on psyllid eggs and nymphs. Subsequently, the predatory capacity and functional response of C. externa were determined in relation to different developmental stages of the psyllid. Predatory capacity was studied for 2nd and 3rd instar larvae of C. externa using eucalyptus leaves naturally infested with 2nd and 3rd instar nymphs of G. brimblecombei. For the functional response, 3rd instar larvae, 24 h after ecdysis, were supplied with psyllid eggs at densities of 1, 2, 4, 8, 16, and 32 eggs per predator larva. The results showed that larvae of both predators exhibit differences in their behavioral parameters, regardless of the developmental stage. Chrysoperla externa larvae are capable of preying on eggs and nymphs in the early instars of the red gum lerp psyllid. The 2nd and 3rd instar larvae of C. externa consumed an average of 19.75 and 38.4 nymphs, respectively. Third instar larvae of C. externa exhibited a type II functional response when fed with different egg densities. Our results suggest that C. externa is a potential control agent for eggs and early instar nymphs of G. brimblecombei. For C. cubana, further studies are necessary to determine its potential in controlling this pest.