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1.
Insects ; 15(10)2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39452336

RESUMEN

Tomato yellow leaf curl virus (TYLCV) causes significant yield loss in tomato production in the southeastern United States and elsewhere. TYLCV is transmitted by the whitefly Bemisia tabaci cryptic species in a persistent, circulative, and non-propagative manner. Unexpectedly, transovarial and sexual transmission of TYLCV has been reported for one strain from Israel. In this study, the potential contribution of the B. tabaci B cryptic species transovarial and sexual transmission of TYLCV (Israel strain, Georgia variant, Georgia, USA) to reoccurring outbreaks was investigated by conducting whitefly-TYLCV transmission assays and virus DNA detection using end point PCR, DNA quantitation via real-time PCR, and virion detection by immunocapture PCR. TYLCV DNA was detectable in four, two, and two percent of first-generation fourth-instar nymphs, first-generation adults, and second-generation adults, respectively, following transovarial acquisition. Post-mating between viruliferous counterparts, the virus's DNA was detected in four percent of males and undetectable in females. The accumulation of TYLCV DNA in whiteflies from the transovarial and/or sexual experiments was substantially lower (100 to 1000-fold) compared with whitefly adults allowed a 48-hr acquisition-access period on plants infected with TYLCV. Despite the detection of TYLCV DNA in whiteflies from the transovarial and/or mating experiments, the virions were undetectable by immunocapture PCR-a technique specifically designed to detect virions. Furthermore, tomato test plants exposed to whitefly adults that presumably acquired TYLCV transovarially or through mating remained free of detectable TYLCV DNA. Collectively, the extremely low levels of TYLCV DNA and complete absence of virions detected in whiteflies and the inability of the B. tabaci cryptic species B to transmit TYLCV to test tomato plants following transovarial and mating acquisition indicate that neither transovarial nor sexual transmission of TYLCV are probable or epidemiologically relevant for TYLCV persistence in this pathosystem.

2.
Plant Dis ; 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39151040

RESUMEN

The traditional understanding of begomovirus transmission exclusively through the whitefly Bemisia tabaci (Gennadius) has shifted with findings of seed transmission in some begomoviruses over the last decade. We investigated the seed transmissibility of cucurbit leaf crumple virus (CuLCrV), a bipartite begomovirus that has recently emerged as a severe constraint for yellow squash (Cucurbita pepo L.) production in the southeastern United States. We found high concentration of CuLCrV in male and female flower tissues of infected squash, including pollen and ovules. The virus infiltrated the fruit tissues including the endocarp and funiculus, which are anatomically positioned adjacent to the seeds. In seeds, CuLCrV was detected in the endosperm and embryo where there are no vascular connections, in addition to the seed coat. The virus was detected in the radicle, plumule, cotyledonary leaves, and true leaves of seedlings grown from seeds collected from infected fruits. In the grow-out test conducted, CuLCrV infections ranged from 17-56% of the progeny plants. To ensure that partial viral genome fragments were not being mistaken for replicative forms of the virus, we performed RCA ̶ PCR and amplified complete DNA-A and DNA-B of CuLCrV from seed tissues, seedlings, progeny plants of CuLCrV infected squash. Near complete DNA-A and DNA-B sequences of CuLCrV were recovered from a progeny plant, further validating our findings. Our results demonstrate that CuLCrV can translocate from vegetative to reproductive tissues of yellow squash, persist within the seeds, and subsequently induce infection in progeny plants, confirming its capacity for seed transmission.

3.
Insects ; 15(6)2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38921145

RESUMEN

The sweetpotato whitefly, Bemisia tabaci (Gennadius) Middle East-Asia Minor 1 (MEAM1), causes significant losses to vegetable crops directly by sap-feeding, inducing plant physiological disorders, and elevating the build-up of sooty mold, and indirectly by transmitting plant viruses. In this study, we evaluated the susceptibility of 20 yellow squash and zucchini (Cucurbita pepo) cultivars to MEAM1, across three growing seasons in the southeastern United States. Weekly sampling of the numbers of MEAM1 adults, nymphs, and eggs were conducted from the fourth week after seed sowing and across 6 weeks during the summer and fall of 2021 and five weeks during the fall of 2022. In general, adult whitefly populations were high during the first week of sampling but decreased as the seasons progressed. The zucchini cultivar 'Black Beauty' harbored the most adults, while 'Green Eclipse Zucchini' was the least attractive zucchini cultivar to the adults in fall 2022. For yellow squash, 'Early Summer' (summer 2021) and 'Amberpic 8455' (summer 2021 and fall 2022) were the cultivars with the highest adult populations, while 'Lioness' (summer 2021) and 'Gourmet Gold Hybrid' (fall 2022) harbored the lowest adult counts. The whitefly egg counts across both vegetables trailed those of adults and peaked in the second week of sampling. The counts of nymphs increased as the seasons progressed, but there was a decline after the second week during fall 2021. For the yellow squash cultivars, 'Gourmet Gold Hybrid', (summer 2021 and fall 2022), 'Lioness', and 'Fortune' (summer 2021) recorded the highest yields. For zucchini, 'Golden Glory' (summer 2021) was the top performer. These results provide valuable information for whitefly management in yellow squash and zucchini based on host plant susceptibility and yield.

4.
J Virol Methods ; 329: 114992, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38936512

RESUMEN

Cucurbit leaf crumple virus (CuLCrV) is among the prominent viruses infecting cucurbits in the USA. Attainable procedures of virus inoculation to crops are prerequisite for screening of resistance against the virus. Because mechanical (non-vector-mediated) infection by cucurbit leaf crumple virus (CuLCrV) is inefficient in economically important crops, screening for CuLCrV resistance is currently laborious and time-consuming using transmission by viruliferous whiteflies. We constructed an infectious partial tandem repeat construct of an isolate of CuLCrV from Georgia, USA, in the plant expression binary vector pCambia2300 and transformed it into Agrobacterium tumifaciens strain EHA105. Agroinfiltration of this construct into the abaxial surface of the leaves of common bean (Phaseolus vulgaris L.) produced a systemic infection characteristic of CuLCrV, although this approach was not successful for yellow squash. However, we report a very efficient and reproducible inoculation procedure established in squash when the leaves were injured with a microneedle and rubbed it with cell suspension harbouring the infectious viral construct.


Asunto(s)
Cucurbita , Enfermedades de las Plantas , Hojas de la Planta , Cucurbita/virología , Enfermedades de las Plantas/virología , Hojas de la Planta/virología , Phaseolus/virología , Vectores Genéticos/genética
5.
Plants (Basel) ; 13(9)2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38732482

RESUMEN

Sweet potato leaf curl virus (SPLCV) is a whitefly-transmitted begomovirus infecting sweetpotato and other morning glory (Convolvulaceae) species worldwide. The virus is widespread at the USDA, ARS, U.S. Vegetable Laboratory (USVL), and testing of germplasm maintained in the breeding program indicates nearly 100% infection in storage roots of materials propagated for at least four years. Prior to the public release of new germplasm, viruses must be eliminated via laborious and time-consuming meristem-tip culture. The identification of virus-free seedlings early in the selection process can offer an alternative to meristem-tip culture. In this study, we investigated the transmission of SPLCV over two years of consecutive field plantings (early and late) of sweetpotato. While SPLCV is endemic at the USVL, virus transmission pressure over the typical cultivation season is unknown, and avoidance of virus transmission paired with the selection and maintenance of clean material may be a viable alternative to virus elimination. In 2022, the storage roots of 39 first-year seedling (FYS) selections were tested for SPLCV after early-season cultivation, revealing a single selection (2.6%) with a positive test. Similar testing was conducted in 2023 with no SPLCV-positive FYS selections detected. To further assess SPLCV acquisition in the field, replicated late-season plantings of each selected FYS (n = 37) were monitored from planting to harvest. Testing was conducted at 60 and 120 days after planting (DAP). Approximately 35% of the bulk samples were infected at 60 DAP, and infection increased to 52.3% by 120 DAP. Testing of individuals within selected positive bulked samples did not support 100% infection at harvest. Altogether, these results demonstrate that SPLCV transmission during early planting is sufficiently low to facilitate the maintenance of virus-free selections, offering an alternative to virus cleaning and a cultivation strategy that may be leveraged for production.

6.
Viruses ; 16(4)2024 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-38675929

RESUMEN

Plants can respond to insect infestation and virus infection by inducing plant defenses, generally mediated by phytohormones. Moreover, plant defenses alter host quality for insect vectors with consequences for the spread of viruses. In agricultural settings, other organisms commonly interact with plants, thereby inducing plant defenses that could affect plant-virus-vector interactions. For example, plant defenses induced by omnivorous insects can modulate insect behavior. This study focused on tomato yellow leaf curl virus (TYLCV), a plant virus of the family Geminiviridae and genus Begomovirus. It is transmitted in a persistent circulative manner by the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), posing a global threat to tomato production. Mirids (Hemiptera: Miridae) are effective biological control agents of B. tabaci, but there is a possibility that their omnivorous nature could also interfere with the process of virus transmission. To test this hypothesis, this study first addressed to what extent the mirid bug Dicyphus hesperus Knight induces plant defenses in tomato. Subsequently, the impact of this plant-omnivore interaction on the transmission of TYLCV was evaluated. Controlled cage experiments were performed in a greenhouse setting to evaluate the impact of mirids on virus transmission and vector acquisition by B. tabaci. While we observed a reduced number of whiteflies settling on plants exposed to D. hesperus, the plant defenses induced by the mirid bug did not affect TYLCV transmission and accumulation. Additionally, whiteflies were able to acquire comparable amounts of TYLCV on mirid-exposed plants and control plants. Overall, the induction of plant defenses by D. hesperus did not influence TYLCV transmission by whiteflies on tomato.


Asunto(s)
Begomovirus , Hemípteros , Insectos Vectores , Enfermedades de las Plantas , Solanum lycopersicum , Begomovirus/fisiología , Solanum lycopersicum/virología , Animales , Enfermedades de las Plantas/virología , Hemípteros/virología , Hemípteros/fisiología , Insectos Vectores/virología , Heterópteros/virología , Heterópteros/fisiología , Defensa de la Planta contra la Herbivoria
7.
Anal Biochem ; 689: 115503, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38453049

RESUMEN

Terpenes play a vital role in plant defense; tomato plants produce a diverse range of terpenes within specialized glandular trichomes, influencing interactions with herbivores, predators, and pollinators. This study employed two distinct methods, namely leaf dip and maceration, to extract trichomes from tomato leaves. Terpene quantification was carried out using Gas Chromatography-Mass Spectrometry (GC-MS). The leaf dip method proved effective in selectively targeting trichome content, revealing unique extraction patterns compared to maceration. The GC-MS method demonstrated high linearity, accuracy, sensitivity, and low limits of detection and quantification. Application of the method to different tomato species (Solanum pennellii, Solanum pimpinellifolium, Solanum galapagense, Solanum habrochaites, and Solanum lycopersicum) identified significant variation in terpene content among these species, highlighting the potential of specific accessions for breeding programs. Notably, the terpene α-zingiberene, known for its repellency against whiteflies, was found in high quantities (211.90-9155.13 µg g-1) in Solanum habrochaites accession PI209978. These findings provide valuable insights into terpenoid diversity for plant defense mechanisms, guiding future research on developing pest-resistant tomato cultivars. Additionally, the study underscores the broader applications of terpenes in agriculture.


Asunto(s)
Solanum lycopersicum , Solanum , Terpenos/análisis , Cromatografía de Gases y Espectrometría de Masas , Extractos Vegetales
8.
Insect Mol Biol ; 33(5): 467-480, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38335444

RESUMEN

The function of DNA methylation in insects and the DNA methyltransferase (Dnmt) genes that influence methylation remains uncertain. We used RNA interference to reduce the gene expression of Dnmt1 within the whitefly Bemisia tabaci (Hemiptera:Aleyrodidae; Gennadius), a hemipteran species that relies on Dnmt1 for proper gametogenesis. We then used RNA-seq to test an a priori hypothesis that meiosis-related genetic pathways would be perturbed. We generally did not find an overall effect on meiosis-related pathways. However, we found that genes in the Wnt pathway, genes associated with the entry into meiosis in vertebrates, were differentially expressed. Our results are consistent with Dnmt1 knockdown influencing specific pathways and not causing general transcriptional response. This is a finding that is also seen with other insect species. We also characterised the methylome of B. tabaci and assessed the influence of Dnmt1 knockdown on cytosine methylation. This species has methylome characteristics comparable to other hemipterans regarding overall level, enrichment within gene bodies, and a bimodal distribution of methylated/non-methylated genes. Very little differential methylation was observed, and difference in methylation were not associated with differences in gene expression. The effect on Wnt presents an interesting new candidate pathway for future studies.


Asunto(s)
Metilación de ADN , Hemípteros , Oocitos , Animales , Hemípteros/genética , Hemípteros/metabolismo , Oocitos/metabolismo , Femenino , ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , ADN (Citosina-5-)-Metiltransferasa 1/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Interferencia de ARN , Vía de Señalización Wnt , Meiosis
9.
Insects ; 14(11)2023 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-37999062

RESUMEN

The challenges that sweet potato whitefly (Bemisia tabaci) creates for vegetable production have increased in the southeastern U.S. Growers must use intensive insecticide spray programs to suppress extremely high populations during the fall growing season. Thus, the objective of this study was to evaluate the use of a reflective plastic mulch and an insect row cover as alternative methods to the current grower practices to manage whiteflies in zucchini (Cucurbita pepo) production. Field experiments were conducted with a two-level factorial experimental design of cover and plastic mulch treatments arranged in a randomized complete block design, with four replications in Georgia in 2020 and 2021, and in Alabama in 2021. Cover treatments consisted of an insect row cover installed on zucchini beds at transplanting and removed at flowering and a no-cover treatment, while plastic mulch treatments consisted of reflective silver plastic mulching and white plastic mulching. During all growing seasons, weather conditions were monitored, whitefly populations were sampled weekly, zucchini biomass accumulation was measured at five stages of crop development, and fruit yield was determined at harvesting. Warm and dry weather conditions early in the growing season resulted in increased whitefly populations, regardless of location and year. In general, the reflective silver plastic mulching reduced whitefly populations compared to the conventional white plastic by 87% in Georgia in 2020, 33% in Georgia in 2021, and 30% in Alabama in 2021. The insect row cover treatment reduced whitefly populations to zero until its removal. Consequently, zucchini plants grown with the insect row cover and reflective silver plastic mulching had an increased rate of biomass accumulation due to the lower insect pressure in all locations. Zucchini grown using silver reflective plastic mulch and row covers had an overall increase of 17% and 14% in total yield compared to white plastic mulch and no-cover treatments, respectively. Significant differences in yield among locations were likely due to severe whitefly pressure early in the fall season, and total yields in Georgia in 2020 (11,451 kg ha-1) were 25% lower than in Georgia in 2021 (15,177 kg ha-1) and in Alabama in 2021 (15,248 kg ha-1). In conclusion, silver plastic mulching and row covers reduced the whitefly population and increased biomass accumulation and total yield. These treatments can be considered ready-to-use integrated pest management practices for growers.

10.
Viruses ; 15(11)2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-38005954

RESUMEN

Cucurbits are economically important crops that are widely cultivated in many parts of the world, including the southern US. In recent years, higher temperatures have favored the rapid build-up of whiteflies in the fall-grown cucurbits in this region. As a result, whitefly-transmitted viruses (WTVs) have severely impacted the marketable yield of cucurbits. In this review, we discuss three major groups of WTVs negatively impacting cucurbit cultivation in the southern US, including begomoviruses, criniviruses, and ipomoviruses. Here, we discuss the available information on the biology, epidemiology and advances made toward detecting and managing these viruses, including sources of resistance and cultural practices.


Asunto(s)
Begomovirus , Hemípteros , Potyviridae , Virus , Animales , Estados Unidos/epidemiología , Enfermedades de las Plantas , Productos Agrícolas
11.
Pathogens ; 12(9)2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37764927

RESUMEN

Whitefly, Bemisia tabaci Gennadius (B cryptic species), transmits cucurbit leaf crumple virus (CuLCrV) in a persistent fashion. CuLCrV affects several crops such as squash and snap bean in the southeastern United States. CuLCrV is often found as a mixed infection with whitefly transmitted criniviruses, such as cucurbit yellow stunting disorder virus (CYSDV) in hosts such as squash, or as a single infection in hosts such as snap bean. The implications of different host plants (inoculum sources) with varying infection status on CuLCrV transmission/epidemics is not clear. This study conducted a series of whitefly mediated CuLCrV transmission experiments. In the first experiment, three plants species: squash, snap bean, and tobacco were inoculated by whiteflies feeding on field-collected mixed-infected squash plants. In the second experiment, three plant species, namely squash, snap bean, and tobacco with varying infection status (squash infected with CuLCrV and CYSDV and snap bean and tobacco infected with CuLCrV), were used as inoculum sources. In the third experiment, squash plants with differential CuLCrV accumulation levels and infection status (either singly infected with CuLCrV or mixed infected with CuLCrV and CYSDV) were used as inoculum sources. Irrespective of plant species and its infection status, CuLCrV accumulation in whiteflies was dependent upon the CuLCrV accumulation in the inoculum source plants. Furthermore, differential CuLCrV accumulation in whiteflies resulted in differential transmission, CuLCrV accumulation, and disease phenotype in the recipient squash plants. Overall, results demonstrate that whitefly mediated CuLCrV transmission between host plants follows a virus density dependent phenomenon with implications for epidemics.

12.
Data Brief ; 49: 109432, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37547168

RESUMEN

The sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), is one of the most destructive pests of sweetpotato worldwide. Genomic analyses of sweetpotato weevils can provide insights into their genetic diversity, population structure, and dispersal as well as provide information to support management strategies. Adult sweetpotato weevils were collected by various methods from Ipomoea batatas L. (sweetpotato) or I. coccinea L. (red morning glory) in the U.S. states of Georgia, Hawaii, South Carolina, and Texas. Genomic DNA was extracted from individual weevil specimens and sequenced using Illumina NovaSeq. A total of 181 GB of 150 base pair (bp) paired-end reads were generated for 40 specimens. Mitochondrial genomes were assembled for each specimen via reference mapping and annotated using Geneious Prime. Full mitochondrial genome sequences range from 17,141 to 17,152 bp with an average GC content of 21.8% and average coverage of 3307 × . A maximum likelihood phylogenetic analysis considering the mitochondrial protein coding genes is provided. Mitochondrial genomes and assembled reads are deposited in NCBI GenBank, providing 40 mitogenomes of C. formicarius elegantulus collected in the U.S.

13.
J Fungi (Basel) ; 9(8)2023 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-37623598

RESUMEN

Previously, Cordyceps javanica Wf GA17, a causing agent of whitefly epizootics in southern Georgia, demonstrated superior temperature tolerance and higher virulence against the whitefly Bemisia tabaci than commercial strains in the laboratory. The post-application persistence and efficacy of this fungus against B. tabaci were compared with that of the commercially available C. javanica Apopka97 strain over a two-year field study in cotton and vegetable crops. When blastospores of both strains were applied alone, whitefly populations were not effectively suppressed. Thus, JMS stylet oil was added to fungal treatments for enhancing efficacy and persistence. For 0-day samples, all fungal treatments caused similar but significant levels of immature mortality regardless of fungal strain, propagule form (conidia vs. blastospores), and application method (alone or mixed with JMS). In follow-up samplings, Wf GA17 blastospores + JMS achieved higher control levels than other treatments in some trials, but the efficacy did not last long. The JMS oil alone caused significant mortality and suppressed whiteflies. Over 90% of spores lost viability 24 h after treatment in all fungal treatments. Across evaluation times, there was no difference between the two fungal strains (conidia or blastospores, alone or combined with JMS), but conidia persisted better than blastospores for both strains. Overall, the field persistence and efficacy of C. javanica did not last long; therefore, improved delivery methods and formulations are needed for enhancement.

14.
Insects ; 14(7)2023 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-37504651

RESUMEN

Ecotoxicological studies often result in reports on the limitation and sometime failures of biological assay data to predict field response to similar treatments. Nevertheless, it is widely accepted that controlled bioassays can better quantify the specific mortality response of a target pest species to a specific toxin. To quantify the relationship between whitefly bioassay and field response data, we evaluated a controlled laboratory bioassay and a concurrent cucurbit field trial method to assess insecticide efficacy for controlling the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). This was based on oviposition and nymphal development. We specifically tested the assumptions that a maximum dose bioassay would more precisely measure insecticide efficacy as compared with a comparable field spray test evaluation, and the response would be equal between the bioassay and the field as a measure of control accuracy for both adult oviposition and development of nymphal stages. To make a direct comparison, we tested the same whitefly population subsamples from 352 plots in eight cucurbit field experiments in Georgia, USA, in 2021 and 2022. The bioassays provide significantly precision for estimating proportional whitefly response. As expected, treatment-specific nonequivalence in immature whitefly counts between the bioassay and field, i.e., a lack of accuracy, only occurred with insecticides that were not highly toxic to all growth stages of whiteflies.

15.
Insects ; 14(6)2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37367326

RESUMEN

We conducted a rapid bioassay method to assess insecticide efficacy for controlling adult sweetpotato whitefly Bemisia tabaci in squash and cucumber crops before insecticide applications. The study aimed to evaluate the accuracy of a 24-hour laboratory bioassay in determining maximum dose insecticide efficacy in the field. Ten insecticides were evaluated using leaf-dip bioassays, and their effectiveness was tested across eight cucurbit field experiments in Georgia, USA, during the 2021 and 2022 field seasons. The maximum dose, defined as the highest labeled rate of an insecticide diluted in the equivalent of 935 L ha-1 of water, was used for all bioassays. Adult survival observed in the bioassay was compared to adult field count-based survival 24 h after treatment. A low concentration (1/10 rate) was used for imidacloprid, flupyradifurone, pyriproxyfen, and cyantraniliprole to assess insecticide tolerance in the whitefly population. Overall, significant positive correlation between laboratory bioassay and field efficacy was reported, explaining 50-91% of the observed variation. The addition of the low dosage was helpful, indicating that no rate response was consistent with susceptibility to the tested insecticide, while a rate response was associated with a loss of susceptibility between 2021 and 2022.

16.
J Insect Physiol ; 147: 104507, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37011857

RESUMEN

The whitefly Bemisia tabaci is a globally important crop pest that is difficult to manage through current commercially available methods. While RNA interference (RNAi) is a promising strategy for managing this pest, effective target genes remain unclear. We suggest DNA methyltransferase 1 (Dnmt1) as a potential target gene due to its effect on fecundity in females in other taxa of insects. We investigated the role of Dnmt1 in B. tabaci using RNAi and immunohistochemistry to confirm its potential conserved function in insect reproduction, which will define its usefulness as a target gene. Using RNAi to downregulate Dnmt1 in female B. tabaci, we show that Dnmt1 indeed has a conserved role in reproduction, as knockdown interfered with oocyte development. Females in which Dnmt1 was knocked down had greatly reduced fecundity and fertility; this supports Dnmt1 as a suitable target gene for RNAi-mediated pest management of B. tabaci.


Asunto(s)
Genes de Insecto , Hemípteros , Animales , Femenino , Control de Insectos , Hemípteros/fisiología , Reproducción , Interferencia de ARN , Oocitos
17.
Pest Manag Sci ; 79(8): 2704-2712, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36905633

RESUMEN

BACKGROUND: Selective insecticides and insecticide-resistant natural enemies are components of chemical and biological methods that can be compatible in an integrated pest management (IPM) program. Many insecticides that are labeled for treatment against insects in Brassica crops have lost their efficacy because of the development of resistance. However, natural enemies can provide an important role in regulating the population of these pests. RESULTS: Survival of Eriopis connexa populations was >80% when exposed to insecticides, except for EcFM exposed to indoxacarb and methomyl. Bacillus thuringiensis, cyantraniliprole, chlorfenapyr and spinosad caused high mortality of P. xylostella larvae, but neither affected E. connexa survival nor its predation upon L. pseudobrassicae. Cyantraniliprole, chlorfenapyr, deltamethrin and methomyl caused high mortality of L. pseudobrassicae, but did not affect E. connexa survival nor its predation upon P. xylostella larvae. According to the differential selectivity index and the risk quotient, chlorfenapyr and methomyl were more toxic to P. xylostella larvae than to E. connexa, whereas indoxacarb was more toxic to E. connexa. CONCLUSION: This study demonstrates that the insecticides B. thuringiensis, cyantraniliprole, chlorantraniliprole, deltamethrin, chlorfenapyr, spinosad, azadiracthin and spiromesifen are compatible with insecticide-resistant adult E. connexa within an IPM program in Brassica crops. © 2023 Society of Chemical Industry.


Asunto(s)
Brassica , Escarabajos , Insecticidas , Mariposas Nocturnas , Piretrinas , Animales , Insecticidas/farmacología , Metomil , Conducta Predatoria , Resistencia a los Insecticidas , Piretrinas/farmacología , Larva
18.
Insects ; 14(3)2023 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-36975915

RESUMEN

Snap bean is an important crop in the United States. Insecticides are commonly used against pests on snap bean, but many pests have developed resistance to the insecticides and beneficials are threatened by the insecticides. Therefore, host plant resistance is a sustainable alternative. Population dynamics of insect pests and beneficials were assessed on 24 snap bean cultivars every week for six weeks. The lowest number of sweetpotato whitefly (Bemisia tabaci) eggs was observed on cultivar 'Jade', and the fewest nymphs were found on cultivars 'Gold Mine', 'Golden Rod', 'Long Tendergreen', and 'Royal Burgundy'. The numbers of potato leafhopper (Empoasca fabae) and tarnished plant bug (Lygus lineolaris) adults were the lowest on cultivars 'Greencrop' and 'PV-857'. The highest numbers of adults were found in Week 1 (25 days following plant emergence) for B. tabaci and Mexican bean beetle (Epilachna varivestis); Week 3 for cucumber beetle, kudzu bug (Megacopta cribraria), and E. fabae; Weeks 3 and 4 for thrips; Week 4 for L. lineolaris; and Weeks 5 and 6 for bees. Temperature and relative humidity correlated with B. tabaci, E. varivestis, bee, and predator ladybird beetle populations. These results provide valuable information on the integrated pest management of snap beans.

19.
Microbiol Resour Announc ; 11(8): e0044622, 2022 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-35862910

RESUMEN

Two novel iflaviruses were detected in the metatranscriptome of the gray lawn leafhopper, Exitianus exitiosus (Uhler). The assembled genome sequence of Exitianus exitiosus virus 1 was 9,858 nucleotides (nt) long and encodes a 3,083-amino acid (aa) polyprotein. Exitianus exitiosus virus 2 was 10,219 nt long and encodes a 2,947-aa polyprotein.

20.
Insects ; 12(5)2021 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-34069347

RESUMEN

Whiteflies (Hemiptera: Aleyrodidae), especially the sweetpotato or cotton whitefly, Bemisia tabaci (Gennadius), are among the most destructive and difficult to manage polyphagous insect pests around the globe [...].

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