Four new species of carabid beetle—Harpalus mckayi sp. n., Harpalus mnguni sp. n., Harpalus nkqwili sp. n., and Harpalus peteni sp. n.—are described using relatively well-preserved compression fossils from an Upper Cretaceous lacustrine rock deposit at the Orapa Diamond Mine in Botswana. All the fossils are assigned in the extant subfamily Harpalinae based on key diagnostic characters, including the general habitus, mandibular scrobe without seta, elongated scutellum, and spiny mesotibia. They are assigned in genus Harpalus due to the following characters: glabrous habitus, hairless eyes, and narrow epilobes of mentum. Notably, all the fossils reported in this study can also be compared with members of the genera Cratognathus, Dichaetochilus, Heterohyparpalus, Aulocoryssus, Acupalpus, Egadroma, and many other genera. Harpalus mckayi sp. n. has unusual two supraorbital pits (instead of only one) located above each eye. Harpalus mnguni sp. n. and H. nkqwili sp. n. are rather similar; but H. mnguni sp. n. has elongated palps and slender antennomeres, whereas H. nkqwili sp. n. has a unique postorbital constriction. Harpalus peteni sp. n. differs by the shape of the eyes and anterior margins. The Harpalinae have been remarkably conservative in their evolution since the Cretaceous and possibly even longer. All of the fossils consolidate the widely documented diversity and widespread distribution of the Carabidae in the Cretaceous and in the Mesozoic at large.Abstract
Thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), are among the main insect pests of lemon production in Mexico. They damage flowers and fruits, thus, requiring several pest management approaches, including biological control. To determine the relationship between the populations of these pests and their main natural enemies, we estimated the population densities of thrips and their natural enemies in the citrus growing area of Apatzingán Valley, Michoacán, Mexico, in five conventional Mexican lemon orchards from May 2018 to December 2022. The detected natural enemies were Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) at a density of 0 to 0.57 individuals per branch, Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae) at 0 to 0.26 individuals per branch, and Amblyseius swirskii (Athias-Henriot) (Acarina: Phytoseiidae) at 0 to 3.18 individuals per branch. Nonlinear exponential regression analyses were conducted with the population density of F. occidentalis, population densities of its natural enemies, and the sum of the population densities of the natural enemies in each orchard. A strong correlation was observed with the mean population density of F. occidentalis and the accumulated population densities of C. rufilabris, H. convergens, and A. swirskii.Abstract
Phthorimaea absoluta (=Tuta absoluta) (Meyrick) (Lepidoptera: Gelechiidae), an invasive pest native to South America, poses a severe threat to solanaceous crops, particularly tomatoes (Solanum lycopersicum L.). Other researchers have often attempted to claim P. absoluta as a polyphagous pest and expanded its host plant list based on unverified observations without evaluating whether the plant could support the completion of the life cycle. Such an approach has led to the inclusion of numerous non-Solanaceae families as hosts, creating ambiguity about the pest’s true host range. To address this issue, we reviewed published articles and extracted host plant records from 63 species across the Solanaceae and non-Solanaceae families. Host plants were assessed for their suitability to support complete, partial, or no life cycle of P. absoluta. Our findings revealed that only a specific subset of host plants, predominantly within the Solanaceae, support the complete life cycle of this pest, defining its true host range as an oligophagous herbivore. In contrast, other recorded host plants permit only partial development or fail to sustain larval survival. A notable finding is the mismatch between female oviposition preferences and larval development, resulting in variability in host plant usage across genera such as Nicotiana and Datura and even within Solanum. These discrepancies may stem from geographic, chemical, and ecological factors. Inconsistent methodologies and limited data pose significant challenges to clarifying the pest’s true host range. This review highlights the need for life cycle data to clarify the host range of P. absoluta. By addressing these gaps, this study advances host specialization theories and supports future research on invasive pests.Abstract
Trichonephila clavata L. Koch (Araneae: Araneidae), the Jorō spider, was first observed in Georgia in 2014. This large, colorful spider has received nationwide attention for its potential to disperse through the United States. Community scientists have the potential to contribute important information to spider conservation biologists, and public captivation with this spider might lead to more spider observations by community scientists. The objectives of this study were to determine whether (1) T. clavata was the dominant observed araneid spider, (2) the presence of T. clavata inspired more community scientists to post observations of spiders and other araneids, and (3) the observed araneid communities differed in states where T. clavata was present and absent. Although T. clavata was the most-observed araneid spider in Georgia according to iNaturalist observations, its presence did not lead to more spider and araneid iNaturalist observations in states with T. clavata than those without, but Argiope aurantia Lucas and Trichonephila clavipes L., the other two most-observed spiders, were observed more often in states with T. clavata. Araneid communities recorded to the Global Biodiversity Information Facility did not statistically differ in Georgia, North Carolina, South Carolina, and Tennessee before and after its first observations in those states. Further observations by community scientists will only help professional scientists, and professional scientists are encouraged to communicate with community scientists about the importance of repeated submissions of observations of all spiders.Abstract
The fruit flies Dacus frontalis Becker and Dacus ciliatus Loew (Diptera: Tephritidae) are major pests of geothermal cucurbit greenhouses in southern Tunisia, causing significant yield losses. This study evaluated soil solarization coupled with the use of geothermal water and plastic film as a sustainable pest management strategy during the fallow period when only pupae of both insects are present in the soil. Solarization with geothermal water at 60°C, combined with black or transparent plastic films as mulches, significantly reduced the number of pupae and subsequent emergence of adult fruit flies in 2021 and 2022. Solarization using black plastic film resulted in the recovery of a mean of only 1 pupa per greenhouse in 2021 and 0.677 in 2022. The mean number of pupae collected from solarization with transparent film was 4.67 pupae per greenhouse in both years. In untreated greenhouses, mean numbers of pupae were 19.3 in 2021 and 18.7 in 2022. No adults emerged from pupae in the solarized greenhouses, whereas in the untreated greenhouses emergence rates were between 43.4% and 45.1%. During the production season, black film solarization reduced fruit infestation by 20.7% (75.3 flies/kg of fruit) in 2021 and 20.3% (73.9 flies/kg of fruit) in 2022. Fruit infestation in treatments with transparent film was reduced 12.7% (63.5 flies/kg) in 2021 and 16.7% (58.1 flies/kg) in 2022. In contrast, untreated greenhouses had the highest infestation levels, with 34% infested fruits (101 flies/kg) in 2021 and 40.7% infested fruits (102 flies/kg) in 2022. These results demonstrate the potential of solarization as a viable pest management tactic and perhaps a sustainable alternative for managing Dacus fruit fly pests in geothermal greenhouses.Abstract
The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), remains a major pest of soybean, Glycine max (L.) Merrill (Fabales: Fabaceae), production in the Upper Midwest, leading to yield losses of up to 40% and it has developed resistance to some insecticides. These challenges underscore the necessity for more integrated pest management approaches, such as cultural control methods. Relay-cropping soybean with a winter cover crop has the potential to suppress some soybean pest populations. Field pennycress or pennycress, Thlaspi arvense L. (Brassicales: Brassicaceae), is currently being domesticated as a new cover crop and oilseed crop. In this study, we evaluated the impact of relay-cropping soybean into a pennycress cover crop on soybean aphid populations across 4 site-years in Minnesota. The experimental design included combinations of two soybean varieties planted with and without pennycress. Soybean aphid populations were monitored weekly by counting aphids on 10 randomly selected soybean plants per plot. Although aphid infestations were relatively low across the site-years, the results demonstrated that soybean relay-cropped with pennycress had lower seasonal aphid abundance (i.e., cumulative aphid-days) than soybean without the cover crop. These findings indicate that relay cropping soybean into pennycress cover crops holds promise as a cultural control tactic to reduce soybean aphid populations, providing a more sustainable pest management option for growers.Abstract
The quality (number of live individuals) of biological control agents, such as parasitoids and predators, is important to ensure the success of biological control programs. Shipment quality of slow-release sachets containing the predatory mite, Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), and release cards containing the whitefly parasitoids, Encarsia formosa Gahan (Hymenoptera: Aphelinidae) and Eretmocerus eremicus Rose & Zolnerowich (Hymenoptera: Aphelinidae), was determined from a distributor/supplier in 2023. Slow-release sachets containing predatory mites were inserted into a mold of clay placed on a 7.6 × 12.7 cm yellow sticky card. The number of adults that emerged and were captured on the yellow sticky card was recorded. Release cards containing parasitized pupae of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), or sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), were placed into a 225-mL Mason jar and a 2.5 × 2.5 cm yellow sticky square was attached to the lid underside. The number of adults captured on the yellow sticky square was recorded. The numbers of N. cucumeris, E. formosa, and E. eremicus adults that emerged from slow-release sachets or release cards varied depending on shipment date. The mean (± SEM) number of adults on the final assessment date was between 156.2 ± 12.9 and 410.0 ± 24.2 for N. cucumeris, 47.8 ± 2.2 and 52.6 ± 1.2 for E. formosa, and 40.0 ± 5.0 and 75.2 ± 9.4 for E. eremicus. Greenhouse producers should assess whether biological control agent shipments are viable when released into greenhouse production systems.Abstract
The aim of this study was to evaluate the ovicidal, larvicidal, and pupicidal activities of various commercial insecticides against Aedes aegypti (L.) (Diptera: Culicidae), a primary vector of several human diseases. Laboratory bioassays were used to evaluate fenpyroximate, etoxazole, spinetoram, pyriproxyfen, flufenoxuron, spinosad, neem oil, soybean oil, and spiromesifen to identify promising treatments. Quasi-field tests followed to assess the practical applicability of these insecticides. None of the tested compounds exhibited significant ovicidal activity. The most effective larvicidal treatments were spinosad, spinetoram, pyriproxyfen, and neem oil, with 95% lethal concentration (LC95) values of 0.029, 24.3, 95.3, and 103.8 mg/L, respectively. Neem oil exhibited the lowest LC95 value against pupae (28.3 mg/L) and was considered the most promising treatment of the nine compounds tested to manage larvae and pupa of Ae. aegypti. In stagnant water, neem oil at 264 mg/L provided 96.9–100% larval mortality over 28 d, with and without 10% water exchange (i.e., simulated rain-induced dilution). At this concentration, pupal mortality exceeded 99% at 1 and 7 d after treatment (72 h of exposure). Neem oil, a natural and cost-effective insecticide, has significant potential for controlling the larval and pupal stages of Ae. aegypti.Abstract
Cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae), is an important pest of brassicas worldwide, including on the Central Coast of California. Although D. radicum larval feeding and damage are reported, the impact of infestation on plant growth and the potential effects of soil type on larval survival have not been fully investigated. Thus, the objectives of this study were to determine (1) the effects of D. radicum infestation on broccoli growth and (2) the performance of D. radicum larvae when exposed to various soil types on the Central Coast of California. As a case study, a D. radicum-infested broccoli field was selected 8 weeks after plant emergence. The health status of plants on the basis of vigor and D. radicum infestation was established using a 1–6 rating scale. Health status and plant development were monitored for 5 weeks. The results demonstrate that D. radicum infestation caused asynchronous plant growth and development of florets, which can potentially result in complete crop loss. Of 18 soil types evaluated on the basis of a laboratory experiment with turnip discs, the Diablo Clay, Lockwood Loam, and Oceano Sandy Loam soils resulted in reduced D. radicum feeding activity relative to other soil types sampled from the Central Coast of California. Delia radicum larval mortality was greatest on the Diablo Clay soil. Thus, vegetable fields with Diablo Clay, Lockwood Loam, and Oceano Sandy Loam soils may benefit from reduced D. radicum densities for Brassica production.Abstract
Oviposition and feeding of herbivorous arthropods influence the plant-arthropod interaction and determine the success in colonization and establishment on their host plant. The avocado brown mite, Oligonychus punicae Hirst (Acari: Tetranychidae), causes severe damage to several crops due to its feeding. This study proposed to evaluate the resistance mechanisms of Moringa oleifera Lamarck (Moringaceae), Phaseolus vulgaris L. (Fabaceae), Persea americana Miller (Lauraceae), and Rosa hybrida L. (Rosaceae) to the attack by avocado brown mite under laboratory conditions. The study was conducted under laboratory conditions at 28 ± 1°C and 70–80% relative humidity (RH), with a photoperiod of 12:12 h (light: dark). Oligonychus punicae females showed no preference to oviposit on M. oleifera (2.10 ± 0.05 eggs/female/day) compared with R. hybrida (2.77 ± 0.06), P. americana (2.73 ± 0.08), and P. vulgaris (3.05 ± 0.08). Females showed a preference to feed on P. vulgaris compared with other host plants. Avocado brown mite recorded the lowest values in r (0.5990 d−1) on M. oleifera foliage square. Moringa oleifera was the most resistant to O. punicae, whereas the most susceptible host plant was P. vulgaris. These results indicate possible resistance of M. oleifera to the attack of O. punicae and that those responses might be due to antibiosis and antixenosis.Abstract
The toxicity and biochemical impact of four novel insecticides (sulfoxaflor, spiromesifen, cyantraniliprole, and flonicamid) were evaluated in laboratory bioassays against the cowpea aphid, Aphis craccivora Koch (Hemiptera: Aphididae). In addition, the inhibitory effect of the insecticides on glutathione S-transferase (GST) was determined using molecular docking analysis. Based on the median lethal concentrations (and associated 95% confidence intervals), spiromesifen (at 1.98 mg/L) and sulfoxaflor (at 3.13 mg/L) exhibited the greatest level of toxicity followed by flonicamid (at 4.02 mg/L) and cyantraniliprole (at 14.93 mg/L). Additionally, sulfoxaflor and cyantraniliprole significantly reduced the activity of α-esterase and cytochrome P450 monooxygenase 48 h after exposure. The insecticidal activity of sulfoxaflor, cyantraniliprole, and spiromesifen was associated with the inhibition of GST activity. The in silico studies of the interactions between GST and the insecticides revealed that the proposed binding patterns of sulfoxaflor and spiromesifen had one hydrogen bond with THR 54 and an arene-H contact with HIS 41, respectively. Thus, cyantraniliprole combined with the receptor through two hydrogen bonds (with HIS 53 and ARG 112) and an arene-H contact with HIS 53. Based on these results, spiromesifen and flonicamid have potential for use in aphid management.Abstract
Scientists are searching for safer substitutes for several hazardous chemicals because of environmental concerns and the development of arthropod resistance to synthetic pesticides. Essential oils pose fewer risks to the environment and human health and are potential alternatives for crop protection; therefore, this study assessed the toxicity and biochemical activity of essential oils from geranium (Pelargonium graveolens L’Hérit) against larvae of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). In addition, molecular docking was used to determine the binding pattern of the detoxifying enzymes glutathione S-transferase (GST), cytochrome P450, and α-esterase with citronellol, the main ingredient (20.91%) of the P. graveolens extract. Concentration–mortality response assays determined lethal concentrations (LCs) of the essential oil as LC15 = 608.52 mg/L and LC50 = 1,820.77 mg/L against second-instar larvae. Additional sublethal studies showed that, compared with the control, exposure of the second-instar larvae with LC15 or LC50 levels of P. graveolens essential oil significantly increased the duration of the larval and pupal stages. Considerable biochemical alterations were found in relation to P. graveolens essential oil biochemical impact on S. littoralis larvae. According to the activity of detoxifying enzymes and the results of the molecular docking study, the citronellol molecule of P. graveolens essential oil exhibited a binding affinity of GST > cytochrome P450 > α-esterase, with an energy score of −5.346, −5.295, and −5.4278 kcal/mol, respectively. The findings confirm the potential of using essential oils in sustainable pest management.Abstract
Bactrocera cucurbitae (Coquillett) and Bactrocera tau (Walker) (Diptera: Tephritidae) are two invasive pests that pose a great threat to melon and fruit crops in tropical and subtropical regions. Previous studies have indicated that there may be a competitive relationship between these two pests because they have similar morphologies and a tendency to damage the same range of hosts. However, no studies have yet confirmed this competitive relationship, which is crucial for predicting the tephritid community structure and population dynamics, as well as for designing management strategies for these pests. In this study, we combined field investigations, literature reviews, and host preference tests to analyze the species association, niche width, and overlap of the two fruit flies to confirm their competitive relationship. We found that B. cucurbitae was more abundant in the wild than B. tau, and there was a negative correlation between them regardless of habitat types. The niche widths of B. cucurbitae and B. tau were 7.50 and 7.42, respectively, and the niche overlap was 0.87 when we analyzed the data from the selected literature. Similarly, the niche widths were 4.95 and 4.44, with a niche overlap of 0.95 when we analyzed data from host preference tests. These results indicate that the two fruit flies co-occur and have a competitive relationship due to their similar niche widths and high niche overlap. The findings offer insights into predicting the field population dynamics and structures of these pests, important for pest monitoring and management.Abstract
Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae: Asopinae) captures and feeds on a wide range of insect pests, making it an important biocontrol agent in agriculture and forestry with significant regional application and promotional potentials. This review summarizes current research information on E. furcellata focusing on taxonomy, morphological characteristics involved in predation, its natural prey, mass rearing, regional application and potential, integrated pest management (IPM) usages, ecological safety evaluations, as well as future prospects for its use in IPM programs.Abstract
Postharvest insect pests pose a significant threat during product storage, diminishing both the quantity and quality of stored goods. Recently, plant-based pesticides have emerged as a promising alternative for managing storage pests. Plant essential oils are rich in biologically active monoterpenes, which have shown considerable potential as pest control agents due to their toxicity to insects. The purpose of the study was to assess the toxicity of six monoterpene compounds (citral, β-citronellol, eucalyptol, geraniol, β-myrcene, and thymol) against rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae). Among the tested monoterpenes, thymol and geraniol exhibited the highest contact toxicity, with 50% lethal concentration (LC50) values of 63.16 and 70.77 μl/cm2 against S. oryzae, respectively, at 72 h after treatment, followed by β-citronellol and citral. The fumigant activity of the compounds tested at concentrations ranging between 20.0 and 100.0 μl/ml of air was highest with β-citronellol (LC50 of 22.12 μl/ml of air), followed by citral (LC50 of 32.23 μl/ml of air) at 72 h after exposure. β-Myrcene and geraniol also exhibited fumigant toxicity but at levels lower than β-citronellol or citral. Among the six monoterpenes, geraniol showed highest repellent activity of 90.00% ±1.44%, followed by β-citronellol (75.00% ± 2.88%) and citral (71.75% ± 1.25%) at 4 h of exposure at 7.5 μl/cm2. In sum, the six tested monoterpenes exhibited moderate to high toxicity against S. oryzae, suggesting that they have the potential to be developed and used as effective alternatives for managing S. oryzae in stored products.Abstract
Beekeeping activities involving Apis mellifera L. (Hymenoptera: Apidae) impact social, environmental, and economic aspects of daily life in Mexico. For this activity, the participation of women is crucial because they attend to, care for, and collect products from the hives. Beekeeping, however, can be significantly limited by arthropod and disease pests, thereby reducing production. This review was undertaken to identify agents or products of natural origin (i.e., biological control) that have been developed or have the potential to combat these pests. We found that managed hives in Campeche, Mexico are plagued by the varroa mite (Varroa destructor Anderson and Trueman) (Acari: Mesostigmata), the small hive beetle (Aethina tumida Murray) (Coleoptera: Nitidulidae), the greater wax moth (Galleria mellonella L.) (Lepidoptera: Pyralidae), and the microsporidia Vairimorpha apis (Zander) Tokarev et al. and Vairimorpha ceranae (Fries et al.) Tokarev et al. (Microsporidia: Nosematidae). Our review revealed at least 47 microorganisms or products of plant or microbial origin that have been assessed and/or developed for management of these pests in A. mellifera hives. All of these products can be easily obtained in Mexico and, thus, hold promise in the management of pests of A. mellifera hives in Mexico.Abstract
A population of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), larvae was collected from cowpeas (Vigna unguiculata [L.] Walpers) from Scooterville, GA (Tift Co.) in the summer of 2022, following a report of control failure after chlorantraniliprole application. The collected larvae were transported to Tifton, GA for study at the Coastal Plains Experiment Station. The 72-h maximum dose leaf-dip bioassays of the field-population determined percent mortality to be 26, 49, and 87% for the insecticide active ingredients chlorantraniliprole, cyantraniliprole, and spinetoram, respectively. In comparison, the percent mortality of a susceptible lab strain exposed to the same insecticides was 76, 88, and 98%, respectively. Previous studies of a ryanodine receptor target site mutation, I4743M, identified in Chinese populations of beet armyworm, demonstrated an association with resistance to diamide insecticides. All screened samples from the diamide-resistant field population were shown to possess this mutation, while samples from the diamide-susceptible lab colony were shown to be wild-type. A second mutation, G4900E, associated with diamide resistance in other lepidopteran species, was not identified in any of the sequenced samples from either population. This is the second report of diamide insecticide resistance in beet armyworm populations from the southeastern United States, and the first report of the I4743M target site mutation in Georgia.Abstract
Chemical insecticides are currently the major management means used against Spodoptera frugiperda (J.E. Smith) larvae on sweet corn (Zea mays L. var. saccharata) in Egypt. However, essential oils-based pesticides (EOs) and new insecticides might also be used. As a first report, this study aimed to assess the effectiveness and biochemical impact of lemongrass (Cymbopogon citratus Stapf) EO, flonicamid, and flubendiamide insecticides alone or in combination for managing S. frugiperda on sweet corn under field conditions. In addition, the dissipation of these compounds was determined in corn seeds and corn husks using the QuEChERS method combined with high-performance liquid chromatography (HPLC-DAD). The field efficacy trials showed that flubendiamide alone or in combination with lemongrass EO was more effective than either lemongrass EO or flonicamid alone or combined. Additionally, biochemical analysis revealed that detoxification enzymes may play an important role in S. frugiperda adaptation to flonicamid and flubendiamide. The residues of flonicamid and flubendiamide in corn seeds were undetectable in all treatments. Conversely, corn husks contained high levels of flubendiamide and flonicamid residues after application at high dosages. Interestingly, the dissipation rates of both tested insecticides increased when combined with lemongrass. The half-life values for flonicamid following the applications on corn husks alone or in combination with lemongrass EO were 4.44 and 2.45 d, respectively, while the half-life values for flubendiamide were 1.25 and 2.72 d, respectively. Our results show the potential use of flubendiamide alone or with lemongrass EO for managing S. frugiperda on sweet corn crops.Abstract
The maize weevil (Sitophilus zeamais Motschulsky) is a significant pest affecting stored seeds and grains, leading to substantial losses in both quantity and quality. Utilizing crushed plant powders derived from specific natural plants offers a promising alternative to synthetic insecticides, which pose risks to both consumers and the environment. This study aimed to evaluate the contact toxicity of Tridax daisy (Tridax procumbens L.) plant powder derived from its aerial parts against S. zeamais when incorporated into jasmine brown rice, Oryza sativa L., grains. Laboratory experiments were conducted at 30°C ± 5°C and 70% ± 5% relative humidity following a completely randomized design with four replications and five treatments. Jasmine brown rice grains were treated with different application rates of 0 (control), 20, 40, 60, and 80 g/kg, with five pairs/replicate of 7-d-old S. zeamais. Results showed that T. procumbens powder exhibited a contact toxicity of 93.08 g/kg of grain after 12 d, resulting in a mortality of 27.5%. Additionally, the F1 generation comprised 51 adults, indicating an 85% reduction in adult progeny emergence. These findings demonstrate the potential of T. procumbens powder as a natural grain protectant to control S. zeamais populations in storage.Abstract
Plant latex contains various compounds related to plant defensive roles against herbivores. The paper mulberry, Broussonetia papyrifera L. (Moraceae), produces latex in every part of the tree. The composition and properties of B. papyrifera latex have been reported; however, its effects on insects have not been reported. This study was conducted to examine the effect of B. papyrifera latex on the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). Trehalase activity was suppressed by latex extracts in vitro at various concentrations, and an examination of the fundamental properties of trehalase inhibitor revealed that it is a heat-stable and proteinaceous molecule larger than 10 kDa. The latex extract reduced insect body mass, egg production, and the number of larvae, pupae, and adults of T. castaneum in a concentration-dependent manner. The reproductive organs in both males and females were affected by latex treatment, resulting in a reduction in the size of mature oocytes and germarium in female beetles. Testicular lobes and accessory glands in male beetles also decreased in size. Trehalase activity in reproductive tissues was suppressed by latex, which led to the reduction of glucose content, but the amount of trehalose was not affected. These findings revealed that the latex of B. papyrifera contains components that suppress the trehalase activity, interfere with the growth and reproductive organs of the red flour beetle, and thus may contribute to the plant’s defense strategy against this insect pest.Abstract
The roots of cassava (Manihot esculenta Crantz) are an excellent source of dietary starch for millions of people and also serve as raw material for several industrial products. Cassava root production, however, is limited by insect, mite and disease pests. Tetranychid mites (Acari; Tetranychidae), until recently considered a minor pest of cassava, have assumed major pest status contributing up to 50 to 80% reduction in root yields, causing severe economic losses. Globally, numerous species of tetranychids have been reported causing damage to cassava. These include Tetranychus urticae Koch (syn = T. cinnabarinus [Poisd.]), T. truncatus Ehara, T. neocaledonicus André, T. kanzawai Kishida, Mononychellus tanajoa (Bondar) (syn = M. progresivus Doreste), M. caribbeanae McGregor, Oligonychus biharensis (Hirst), O. gossypii (Zacher), and Eutetranychus orientalis (Klein). Various studies have been undertaken and reported to explore methods (e.g., cultural methods, biological control, botanicals, host plant resistance, conventional chemical insecticides) to mitigate mite damage to cassava and manage their populations. This present work is a review of the pertinent scientific literature on the cassava mite complex, its economic impact, and potential management strategies for the pests.Abstract
Mexico is one of the major exporters of a variety of berries worldwide. Thrips (Thysanoptera) are highly attracted to berry crops, and several species can become serious pests that limit berry yield. Given the pest status of thrips in berry production and the magnitude and importance of berries for export in Mexico, this study was conducted to survey and identify the thrips fauna associated with commercial berry orchards in Mexico. We sampled berry plants in 41 commercial plantations of blackberry (Rubus spp.), blueberry (Vaccinium spp.), raspberry (Rubus spp.), and strawberry (Fragaria × ananasa) in Guanajuato, Jalisco, Michoacán, and Sinaloa during spring and summer 2020. Our study collected 4,394 thrips specimens belonging to 19 species of thrips. Of those, 53.7% were collected from blackberry, 16.1% from blueberry, 15.5% from strawberry, and 14.8% from raspberry. The predominant species in the four berry crops was Frankliniella occidentalis (Pergande). Its relative abundance with respect to other species of thrips collected was 52.9% in blueberry, 69% in raspberry, 79.6% in blackberry, and 88.7% in strawberry. The second most abundant species was Scirtothrips dorsalis Hood, varying from 2.6% in strawberry to 24.6% in blueberry. Other important phytophagous species recorded were Frankliniella cephalica (Crawford) and Frankliniella gossypiana Hood. These four species are invasive, polyphagous, and widespread in Mexico; thus, economic damage by one or more of these species can be expected in locales where management measures are not appropriately applied to avoid economic losses. Data gathered in this survey, coupled with information provided by related studies conducted in Mexico, should serve as a basis for further research dealing with monitoring and management of thrips populations.Abstract
The mosquito Aedes aegypti (L.) (Diptera: Culicidae) transmits arboviruses including the causative agent for yellow fever and threatens human health in tropical and subtropical areas. To reduce the incidence of infection, a variety of tactics is being developed to keep the population density of this vector mosquito as low as possible. Laboratory research directed to this end requires maintaining laboratory colonies of the insect, which, in this case, requires providing immobilized live animals to A. aegypti adult females for a source of blood for production of viable eggs. Using live animals for this procedure is costly, time consuming, and requires rearing mammalian species in the laboratoy. This study evaluated the impact of supplying the adult females with blood from a domestic pig (Sus scrofa domestica L.) mixed with an anticoagulant (7 ml of heparin per liter of blood) on the oviposition rate of A. aegypti. Feeding A. aegypti females with pig blood obtained from a slaughter facility and mixed with heparin produced more eggs (6,994 ± 168) than those allowed to feed on a living hamster as a source of blood (5,483 ± 171). Thus, this methodology is more efficient and economical than the current use of live animals to feed females of A. aegypti.Abstract
Black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), larvae are renowned for their bioconversion of organic waste into nutrient-rich supplements for various applications. In previous studies, the predominant genera of gut bacteria show a large variability among fly larvae, likely due to variability in diets. The ability of catabolic degradation by black soldier fly larvae might be ascribed to intestinal microorganisms. Diets can influence the gut microbiota of H. illucens. However, the effect of distinct foods on bacterial communities of gut bacteria is poorly understood. For this purpose, we undertook this study to assess the impacts of diet on the structure and function of the microbial communities in the gut of black soldier fly larvae fed with representative types of diets. We found that the most abundant bacteria in the black soldier fly larvae gut metagenome were Morganella (17.02%), Enterococcus (10.27%), Paenibacillus (9.50%), Klebsiella (7.29%), and Enterobacteriaceae (10.27%) and, thus, represent the core microbiome. Our results provide insights into the bacterial genes in H. illucens the larval gut, and we concluded that the microbiota structure and function could be shaped by the edible mushroom residue diet. Characterizing the interplay between the gut microbiome and black soldier fly larvae diets helps to clarify the underlying degradation processes and may contribute to improved large-scale black soldier fly larvae rearing. These data sets help to exploit the microbiological optimization of H. illucens as a sustainable insect for industrial rearing and the microbiome for novel biotechnological applications.Abstract
Imidacloprid, one of the neonicotinoid pesticides, is widely used in various types of farmlands globally, causing negative effects on beneficial insects. The stink bug Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae) is an effective generalist predator that provides natural control of Lepidoptera, Coleoptera, and other insect pests. Walking behavior is crucial for these predators; however, the effects of imidacloprid on their walking, and thus searching, behavior remain unknown. We measured walking behavior by using a locomotion compensator to assess the effects of imidacloprid. Acute exposure to imidacloprid significantly reduced the mean walking speed of nymphs (30.6–51.9% depending on instar), adult females (52.0%), and adult males (40.5%). Walking time also was reduced by exposure to imidacloprid in nymphs (27.1–40.5%), adult females (48.2%), and adult males (36.0%), whereas walking distance was reduced in nymphs (8.4–19.8%), adult females (25.2%), and adult males (15.0%). These results reveal that imidacloprid impairs the walking behavior of stink bugs, emphasizing the need to consider the negative effects of neonicotinoid pesticides on the pest control efficacy of natural enemy insects.Abstract
Rice–crab cocropping refers to a new type of ecological aquaculture technology that involves raising crabs (Eriocheir sinensis H. Milne Edwards) in rice fields. To investigate whether crabs affect the community of spiders in the rice fields, we surveyed the species composition of spiders in two types of rice production fields—a rice–crab cocropping paddy and a conventional paddy—over two growing seasons. The fields were representative of the rice fields in Panjin City, Liaoning Province, China. We collected a total of 3,406 spiders representing 27 genera and 10 families over the duration of the study. The number of spiders in rice–crab cocropping paddy fields was significantly higher than in conventional paddy fields, but there was no significant difference in the types of spiders in the two types of paddy fields. An analysis of spider community diversity using Simpson's index, Shannon–Wiener diversity index, Pielou's index, and Margalef's index revealed no significant differences between the rice–crab cocropping paddy and the conventional paddy throughout the survey period. The evenness index and the richness index exhibited a positive relationship, whereas the dominance index showed a negative relationship. The dominant species in the two cropping systems was Pirata subpiraticus Boes. et Str. (Araneae, Lycosidae). Overall, we found no impact of cocropping with crabs on the composition and characteristics of the spider community.Abstract