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
Pollination by bees plays a critical role in the viability of life on this planet from food crop productivity to biodiversity of ecosystems; however, their populations, globally, are in decline. Contributing factors include pesticides, climate change, diseases, and invasives, but most notable, are habitat degradation and fragmentation due to agricultural intensification and urbanization. Research has shown that conservation and restoration of land can help to restore bee abundance and diversity. One opportunity to establish habitat which will attract and provide resources for bees is eroded lands. Recommendation for restoration of eroded land usually includes planting with a number of quick growing native and non-native grasses, which do little for bee conservation. In our study, we incorporated floral resources into an erosion mitigation seed mix specifically selected for their ability to attract bees and thrive in the Piedmont region of Georgia. Plots that incorporated these flowering plants had a greater abundance, richness, and diversity of bees compared with those plots that only contained grass. Bees were 30 times more abundant in wildflower-enhanced plots. Of the flowering plants selected, the ones that survived and bloomed well were Rudbeckia hirta L. (Black-eyed Susan), Chamaecrista fasciculata (Michaux) Greene (partridge pea), Eryngium yuccifolium Michaux (rattlesnake master), Pycnanthemum muticum (Michaux) Persoon (mountain mint), and Coreopsis lanceolata (L.) R. Brown (Lanceleaf coreopsis). The most numerous bees collected by direct observation capture “bee to flower” or cross plot sweep netting “sweeps” were in the genera Lasioglossum, Halictus, and Bombus.Abstract
Rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), is one of the most significant pests of corn (Zea mays L.) and other stored grains. Historically, synthetic insecticides have been widely used to control pest populations due to their effectiveness, convenience of storage and application, and persistent activity. This study aimed to assess the toxicity profiles of four commonly used insecticides, including pirimiphos-methyl, deltamethrin, deltamethrin plus (S)-methoprene, and malathion, to rice weevil adults. The weevils were exposed to a range of concentrations of each insecticide to generate concentration–mortality response curves and median lethal concentrations (LC50) of each insecticide. Pirimiphos-methyl exhibited the highest toxicity to the adult weevils, with an LC50 of 0.74 ppm (95% confidence limit [CL], 0.57–0.92). Based on nonoverlapping 95% CLs, we determined that the LC50 of pirimiphos-methyl was significantly lower than the LC50 of malathion (7.08 ppm [95% CL, 5.44–9.01]), deltamethrin (9.11 ppm [95% CL, 6.89–12.6]), and deltamethrin plus (S)-methoprene (13.94 ppm [95% CL, 9.71–18.60]). Thus, the relative toxicity of these four insecticides to adult rice weevils was pirimiphos-methyl > malathion > deltamethrin > deltamethrin plus (S)-methoprene. We subsequently compared the LC50 value of each insecticide with that of the label-recommended application rate and found that only malathion aligned with the recommended label rate. These findings could prove useful in refining application rates for the effective control of rice weevils infesting stored grains.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
Ericerus pela Chavannes (Hemiptera: Coccoidae) is a typical scale insect that can secrete a waxy covering over its body to protect itself from adverse factors. This insect significantly damages glossy privets and ash trees in most regions of China. The fatty acyl-CoA reductase (FAR) gene is a crucial enzyme in the cutin, suberine, and wax biosynthesis pathways in these insects and also in fatty acid metabolism. Herein, a synthesized double-stranded RNA of the FAR gene in E. pela (dsEpFAR) was used to explore the effects of dsEpFAR on the expression of EpFAR and secretion of wax and development of E. pela. The results showed that a high concentration of dsEpFAR could cause mortality of male nymphs. After a male nymph was treated with a low dose of dsEpFAR, the transcription level of EpFAR was significantly downregulated, the expression level of EpFAR protein was reduced, and the quantity of wax was markedly decreased, suggesting that EpFAR is a key gene in the biosynthesis of wax and that dsEpFAR can interfere with the gene EpFAR and disrupt the process of wax secretion. The growth and development of male nymphs were also significantly influenced by dsEpFAR treatment, leading to a significantly decreased weight and earlier nymph-to-pupae transition. The findings enhance the molecular understanding of male E. pela wax secretion and facilitate the development of EpFAR-based interference with wax secretion for the integrated management of male E. pela.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
(L.) (Lepidoptera: Plutellidae) is the primary pest of broccoli (Brassica oleracea var. italica von Plenck), and it holds the distinction of having the highest number of documented cases of insecticide resistance among insect pests, which complicates its management. The utilization of plant extracts is considered an alternative approach. Therefore, this study aimed to determine the efficacy of commercial plant extracts for the control of P. xylostella. Nine commercial extract products were evaluated, and their effects were compared with Inex-A® + distilled water (control group) and Exalt® (commercial control). Toxicity assays were conducted using third-instar larvae by topical application bioassay. Oviposition inhibition was assessed along with adult female repellency by exposing females to treated surfaces. To determine the residual effect on feeding and oviposition inhibition, third-instar larvae and 3- to 6-d-old adult females were used, respectively, with residual effects measured at 2, 4, 6, 8, and 10 d postapplication. Nimicide 80 (Ultraquimia, Morelos, Mexico) exhibited a mortality rate of 35% of third-instar larvae. Garlimax (Plant Health Care, Azcapotzalco, Mexico) inhibited oviposition by 80%, and demonstrated 85% repellency. The residual effect of Garlimax persisted for 4 d, resulting in a reduced percentage of the consumed area and egg oviposition. The findings of this research highlight the effectiveness of these two products, Nimicide 80 and Garlimax; however, field evaluations are recommended to verify the consistency of their biological effects.Plutella xylostella
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
A fossil thrips is described using a single compression fossil from an Upper Cretaceous deposit, the Orapa Diamond Mine in Botswana. It is the first record of a Cretaceous thrips from Africa. It is diagnosed by the following characteristics: general habitus; narrow, straplike forewing and hindwing with fringe cilia; with forewing becoming progressively larger in distal third; and abdomen with dense transversal rows of microtrichia and terminal setae. The specimen is complete, except that the antennae are absent. At Orapa, the fossil thrips would have been possibly found feeding on leaves, stem or flower tissues of both gymnosperms and angiosperms in and around the crater lake. The fossil thrips adds to the taxonomic diversity of the Orapa fauna. Moreover, it broadens the knowledge of the diversity, geography and evolution of Mesozoic Thysanoptera.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
Entomopathogenic fungi in the clade Ophiocordyceps unilateralis (s.l.) parasitize formicine ants (more commonly known as carpenter ants), resulting in fungal fruiting bodies that emerge from the head of the infected ant. This phenomenon is better known as the “zombie-ant fungus.” In Oak Ridge, Tennessee, 191 infected ant specimens found on deciduous understory shrubs and saplings were collected from May to December 2022 and from March to May 2023. The diameter of stems on which these infected ants were attached was measured, host plant species were determined, and various morphologic characteristics (e.g., stroma length and perithecial plate diameter) of this fungus were documented. Deoxyribonucleic acid extractions and polymerase chain reaction analysis were conducted to confirm the identity of the fungus. Our results confirmed the presence of a fungal species within the Ophiocordyceps clade. Ophiocordyceps kimflemingiae was found infecting Camponotus americanus Mayr attached to stems of several understory shrubs and saplings, such as Lindera benzoin (L.) Blume (spicebush), Ulmus spp. (elm), Acer spp. (maple), Betula spp. (birch), and others. The size of fungal morphologic characteristics varied widely. For example, fungal stroma length ranged from <1 to >30 mm and perithecial plate diameter ranged from as small as 0.1 to >1.5 mm. This research has expanded the known geographic distribution of this fungus, demonstrated fungal morphologic variation, contributed to ecologic knowledge on stem diameter and mandibular death grip of infected ants on deciduous host plants, and expanded the listing of known plant species inhabited by infected ants.Abstract
Licorice of the taxonomic genus Glycyrrhiza is a traditional Chinese medicinal plant. Its large-scale cultivation is threatened by insect pests, including the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). Our study (1) examined the preference of B. tabaci for G. uralensis Fischer ex de Candolle, G. glabra L., and G. inflata Batalin through caged trials; (2) identified the volatile organic compounds (VOCs) released by the three Glycyrrhiza species using headspace gas chromatography–mass spectrometry (HS-GC-MS); and (3) screened the olfactory behavior responses of B. tabaci to the key VOCs identified. The caged host preference trial showed that B. tabaci had a clear preference for G. uralensis over G. inflata and G. glabra. Through HS-GC-MS analysis, we identified 26, 33, and 31 VOCs from G. uralensis, G. glabra, and G. inflata, respectively. (3Z)-Hexen-3-ene-1-yl acetate, trans-3-hexen-1-ol, cis-3-hexen-1-ol, 3-carene, and β-pinene were selected for further olfactory response assays on the basis of variable importance projection values and quantity differences. From these, we learned that cis-3-hexene-1-ol and trans-3-hexene-1-ol, abundant in G. uralensis, attract B. tabaci, whereas 3-carene and β-pinene, abundant in G. inflata, repel B. tabaci. The different VOCs from these three species of licorice may be primary factors affecting the preference for and feeding on cultivated licorice by B. tabaci. Our results will facilitate studies on the potential of using selected VOCs for managing B. tabaci, perhaps in push–pull strategies of their use against the pest.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
Mosquitoes transmit numerous diseases, including malaria and dengue fever, making mosquito control crucial for managing the spread of these and other illnesses. Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) holds promise for the biological control of mosquito vectors but faces challenges such as low pathogenicity, lengthy infection periods, reduced longevity, and a dependence on specific environmental conditions (e.g., temperature and humidity) for spore germination, thus impacting its efficacy. To address this, a strain of B. bassiana was engineered to carry the SPHvt/GNA fusion pathogenicity protein-encoding gene. A plasmid containing the gpdA promoter, GFP gene, and SPHvt/GNA gene was constructed using molecular cloning techniques, including digestion and ligation, based on the base plasmids pBarGPE1 and pBarGFP. The engineered vector plasmid pBarGFPSPHvt/GNA was integrated into the genome of B. bassiana Bb252 through Agrobacterium tumefaciens-mediated fungal genetic transformation, resulting in B. bassiana strains with the SPHvt/GNA fusion pathogenicity protein-encoding gene. These transgenic strains were identified through fluorescence screening and confirmed at the genomic, transcriptional, and protein levels. A spore suspension of Bb252::BarGFPSPHvt/GNA was applied to Anopheles stephensi Liston (Diptera: Culicidae) larvae. The effect of pathogenicity on larval survival was assessed, and the infection process was monitored. The results indicated that the construction of a transgenic B. bassiana strain for potential management of mosquito larvae.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
Since invading Xinjiang, China in 2017, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), commonly known as the tomato leafminer or the South American tomato pinworm moth, has continuously expanded its scope of devastation. Because flight is a major means by which insects disperse, an insect flight mill was employed to elucidate the physiological boundaries and basic parameters of T. absoluta flight biology. The system was used to measure the average flight distance, flight time, and flight speed of adult male and female T. absoluta of different ages, including 5-d-old (post emergence) adults in different mating states that had received supplementary nutrition (5% honey water). Tests of 12 h of continuous suspension in a flight mill showed that 4 through 7-d-old adults had strong flying ability, but 5-d-old adults were the strongest flyers. The mean (±SEM) flight distance, flight time, and flight speed of 5-d-old females were 1.805 ± 0.040 km, 1.467 ± 0.036 h, and 1.231 ± 0.226 km/h, respectively. The mean (±SEM) flight distance, time, and speed of 5-d-old males were 1.627 ± 0.363 km, 1.950 ± 0.056 h, and 0.834 ± 0.202 km/h, indicating significant differences in flight ability between male and female adults. After feeding on 5% honey water, the flight ability of 5-d-old T. absoluta improved significantly compared with the control. The distance, time, and flight speed of honey-water fed 5-d-old virgin females increased by 16.73%, 8.32%, and 8.37%, compared with the control (fed honey-free water). The flight distance, time, and speed of 5-d-old males increased by 7.87%, 0.56%, and 7.07% respectively, compared with the control. After mating, the distance, time, and flight speed of 5-d-old female adults increased by 11.91%, 0.48%, and 11.29% compared with virgin female adults. However, after 5-d-old males mated, their corresponding flight ability decreased by 11.13%, 3.34%, and 7.34%, compared with virgin male adults. In summary, sex, supplementary nutrition, and mating status all have a significant impact on the flight ability of T. absoluta.Abstract
Grasses such as sorghum, (Sorghum bicolor (L.) Moench), are rarely considered as an important food resource for pollinators. Here, we report insects collecting or consuming pollen of sorghum over the 8-wk flowering period of a mapping population in Tifton, GA. We also examine the response of insects to plant morphological traits and disease damage and the ability of bumble bees (Bombus impatiens) to cross-pollinate sorghum. The most numerous insect observed collecting/consuming sorghum pollen was the hover fly Toxomerus politus Say (i.e., the maize calligrapher) followed by honey bees (Apis mellifera L.), lined earwigs (Doru taeniatum Dorhn), lovebugs (Plecia nearctica Hardy), southern carpenter bees (Xylocopa micans Lepeletier), common eastern bumble bees (Bombus impatiens Cresson), exotic stripetails (Allograpta exotica Wiedemann), margined soldier beetles (Chauliognathus marginatus F.), a signal fly (Rivellia sp. Robineau-Desvoidy), and a dusky-winged hover fly (Ocyptamus fuscipennis Say). Maximum flowering occurred at Week 3, which coincided with the maximum number of maize calligraphers, bumble bees, and honey bees observed. A positive linear relationship was seen between the number of flowering plots and the number of maize calligraphers and honey bees. The probability of observing a bee on a panicle increased as plant height increased, whereas the probability of observing a bee or hover fly decreased as plant disease percentage increased. These results suggest that inflorescence abundance, plant height, and plant disease impact bee visitation in sorghum. Furthermore, field-captured bumble bees successfully fertilized sorghum in a greenhouse study, suggesting that bumblebees can pollinate sorghum flowers in field conditions.Abstract
A survey was conducted between 2019 and 2022 to identify natural enemies of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), in the provinces of Şırnak, Siirt, Batman, Diyarbakır, Mardin, Şanlıurfa, Adıyaman, Gaziantep, and Kilis in the Southeastern Anatolia Region of Turkey. Sampling using several different techniques was conducted in agricultural, nonagricultural, and forested areas throughout the duration of the study. We identified natural enemies of B. tabaci, which causes significant crop losses in Turkey and worldwide, with the objective of reducing chemical control in favor of promoting biological control of the pest in the coming years. In our survey, we collected and identified 37 species of predators and 2 species of parasitoids as natural enemies. Of those, the greatest number of species were from the family Coccinellidae (Coleoptera). Coccinella septempunctata (L.), Hippodamia variegata (Goeze), and Orius laevigatus (Fieber) were found in all provinces surveyed.Abstract
This study investigated the effect of soy-based diets supplemented with porcine blood (PB) on the diet's external morphology, nutritional efficacy, and health impacts on honey bees, Apis mellifera L. (Hymenoptera: Apidae). Scanning electron microscopy revealed that the control diet (maize bee bread) displayed ruptured granules with small particles, whereas the soy-based diets showed varying degrees of protein gelatinization and aggregation depending on the presence of PB. Nutritional analysis indicated that maize bee bread was used as a positive control contained 12.2% protein and provided 312.89 kcal/100 g, whereas the formulated soy-based diets with skim milk or PB showed 13–15% protein, meeting the required needs for optimal honey bee health and development. Survival and longevity assessments showed no significant difference in lifespan between honey bees fed with artificial diets and the control, but all treatment groups outlived the negative control, which fed only on syrup. Moreover, the diameter of the hypopharyngeal gland acini, a key indicator of the nutritional state and health in honey bees, was significantly larger in honey bees fed protein-enriched diets compared with those receiving only syrup. These findings underscore the potential of soy-based artificial protein diets, especially when enhanced with PB, to support honey bee health and longevity, comparable with natural pollen sources.Abstract
Jasmonic acid (JA) plays an important role in the indirect plant-mediated interactions between rose powdery mildew (Podosphaera pannosa [Wallr.: Fr.] de Bary) and Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on their shared host Rosa chinensis Jacquin. Bioassays showed that the total number of eggs laid by S. exigua on rose twigs decreased significantly after the twigs were treated with exogenous JA. Gas chromatography coupled with mass spectrometry (GC-MS) showed that the volatile organic chemicals (VOCs) from roses, including alkanes, terpenes, aldehydes, ketones, alcohols, and esters, were significantly changed following treatment with JA. Based on gas chromatography-electroantennographic detection (GC-EAD) and GC-MS analysis, the electrophysiological responses of S. exigua moths could be elicited by 8 compounds from the JA-induced roses, including 3-carene, 1-dodecanol, methyl stearate, 1-tetradecanol, hexadecane, eucalyptol, β-myrcene, and 1-iodododecane. Among these chemicals, the first 6 exhibited significant repellent activity to ovipositional behaviors of the gravid moths, while the latter 2 were attractive. The inhibition index of methyl stearate at a concentration of 15 mg/ml reached 65.12%. On the other hand, the quantity of the first 6 chemicals increased significantly and the latter two decreased due to the JA induction. These results reveal a new mechanism for resistance in rose plants against S. exigua. After JA induction, the rose plants appear to up-regulate the biosynthesis of the chemicals with repellent activities against S. exigua and, in the meantime, down-regulate the attractant chemicals.Abstract