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1.
Exp Appl Acarol ; 84(2): 407-418, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33970407

RESUMO

Tetranychus urticae Koch (Acari: Tetranychidae), twospotted spider mite, is a major secondary pest of strawberry and can cause significant yield loss. Tetranychus urticae is typically controlled using miticides, which has led to rapid resistance development. In South Carolina (USA), extension agents and growers have reported field failures of miticides (inadequate pest suppression), but resistance has not been quantitatively determined. In 2018, we determined the level of miticide resistance of six T. urticae populations found on strawberry across South Carolina. We examined efficacy of all miticides registered for use on US strawberry by conducting an initial diagnostic bioassay at 20% of the maximum labeled field rate. Any population × active ingredient combination resulting in < 55% mortality was identified as 'potentially resistant' and concentration-response bioassays were then conducted to calculate LC50 values for an individual population. These values were compared with those of a known-susceptible laboratory population to calculate resistance ratios (RR). Our results indicate that examined South Carolina populations of T. urticae from strawberry were highly resistant to bifenthrin (RR = 100-60,000) and there was reduced susceptibility to fenbutatin-oxide (RR = 25-123). The 'Sardinia' population had decreased abamectin susceptibility (RR = 25). No resistance to hexythiazox, etoxazole, acequinocyl, bifenazate, fenpyroximate, spiromesifen, or cyflumetofen was found. Based on available data, it appears that miticide resistance is not a likely cause of field failures and issues related to application error and coverage should be investigated. Overall, this work supports the need to reduce the use of broad-spectrum pesticides and older products, in favor of newer miticide chemistries due to resistance issues.


Assuntos
Acaricidas , Fragaria , Tetranychidae , Animais , Itália , Controle de Pragas , South Carolina
2.
J Insect Sci ; 21(3)2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33974081

RESUMO

The minute pirate bug Orius insidiosus (Say) is an important predator in mango agroecosystems. It attacks several species of thrips, particularly Frankliniella invasor Sakimura, which is considered a species of economic importance in mango. We investigated the effect of six diets on the development, survival, and reproduction of O. insidiosus: 1) first instars of F. invasor, 2) second instars, 3) adults, 4) pollen, 5) pollen plus thrips larvae, and 6) water. Individuals fed on thrips larvae, with or without pollen, completed their immature development significantly faster. Nymphs of O. insidiosus were able to complete their development feeding on pollen only, while individuals that received water as a diet were unable to reach the adult stage. The highest intrinsic growth rate was obtained when O. insidiosus were fed on pollen plus thrips larvae, and the lowest when individuals were fed on thrips adults. Our studies show that a diet of pollen plus F. invasor larvae is optimal for O. insidiosus development and population growth.


Assuntos
Agentes de Controle Biológico , Heterópteros/crescimento & desenvolvimento , Tisanópteros , Ração Animal , Animais , Larva/crescimento & desenvolvimento , Ninfa/crescimento & desenvolvimento , Controle de Pragas , Pólen , Comportamento Predatório
3.
J Insect Sci ; 21(3)2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34047334

RESUMO

The present investigation was carried out to study the biological parameters and orientation of Sitophilus oryzae (L.) toward wheat cultivar HPW-236 and mixed grains of different cultivars (HPW-155, HPW-236, HPW-249, HPW-349, HPW-360, HS-490, and VL-892). The incubation period, larval period, pupal period, and total life cycle period of S. oryzae was longer when fed on mixed grains as compared to HPW-236. Also, the weevils were more oriented toward HPW-236 and lower germination rates were observed from HPW-236 than mixed cultivars when exposed to S. oryzae. We also evaluated quantitative losses caused by S. oryzae in different cultivars of wheat recommended in the northwestern Himalayas under free-choice conditions. The weevil inflicted greater damage and weight loss in grains of HPW-236 while it was negligible in the case of HPW-360 and HPW-249. HPW-236 which is the most cultivated variety of wheat in northwestern Himalayas proved to be highly susceptible to the weevil and provided a more suitable environment for weevil's development. Therefore, this particular cultivar can be avoided for prolong storage and the farmers should prefer cultivars such as HPW-360 and HPW-249, which proved to be least affected the weevil.


Assuntos
Controle de Pragas , Triticum , Gorgulhos , Animais , Produtos Agrícolas , Grão Comestível , Gorgulhos/crescimento & desenvolvimento , Gorgulhos/fisiologia
4.
J Insect Sci ; 21(2)2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33822127

RESUMO

Sugarcane spittlebugs are considered important pests in sugarcane crops ranging from the southeastern United States to northern Argentina. To evaluate the effects of climate variables on adult populations of Aeneolamia varia (Fabricius) (Hemiptera: Cercopidae), a 3-yr monitoring study was carried out in sugarcane fields at week-long intervals during the rainy season (May to November 2005-2007). The resulting data were analyzed using the univariate Forest-Genetic method. The best predictive model explained 75.8% variability in physiological damage threshold. It predicted that the main climatic factors influencing the adult population would be, in order of importance, evaporation; evapotranspiration by 0.5; evapotranspiration, cloudiness at 2:00 p.m.; average sunshine and relative humidity at 8:00 a.m. The optimization of the predictive model established that the lower and upper limits of the climatic variables produced a threshold in the population development rate of 184 to 267 adult insects under the agroecological conditions of the study area. These results provide a new perspective on decision-making in the preventive management of A. varia adults in sugarcane crops.


Assuntos
Hemípteros/crescimento & desenvolvimento , Dinâmica Populacional , Saccharum , Animais , Argentina , Inteligência Artificial , Clima , Produtos Agrícolas , Análise Fatorial , Modelos Estatísticos , Controle de Pragas , Sudeste dos Estados Unidos
5.
J Insect Sci ; 21(2)2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33822128

RESUMO

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae), is the most important coffee pest in most of the coffee growing countries. CBB females leave old dry berries after harvest and search for dry noninfested berries on the plant or on the ground to lay eggs or to use as refuge until new berries are available on the coffee trees in the following season. The CBB infestation level and emergence from berries on the ground or on the plants were evaluated in two fields post-harvest in the Spring in Brazil over two seasons. Twenty infested or noninfested berries in separate cages (250 ml plastic cups) were placed on the plants or on the ground under the tree canopy, in each field. The number of infested berries and CBB females that emerged from the infested berries were recorded weekly. CBB emergence was higher from berries on the ground than those on the coffee trees in both seasons, whereas CBB infestation was higher on coffee berries on the plants than those on the ground in season I. Insolation (hours of sunlight) and temperature were the main covariates that affected emergence and infestation by this insect. The results are discussed for monitoring CBB during the time of dispersal with implications on integrated management of this pest.


Assuntos
Coffea , Dinâmica Populacional , Gorgulhos/crescimento & desenvolvimento , Animais , Clima , Produtos Agrícolas , Monitorização de Parâmetros Ecológicos , Análise Fatorial , Controle de Pragas , Plantas , Sementes , Luz Solar , Temperatura , Gorgulhos/fisiologia
6.
J Insect Sci ; 21(2)2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33844017

RESUMO

The codling moth Cydia pomonella (L.) (Lepidoptera: Tortricidae) is a destructive pest of apple (Malus domestica (Rosales: Rosaceae)), pear (Pyrus spp. (Rosales: Rosaceae)), and other pome tree fruits; outbreaks cause significant ecological and economic losses. In this study, we used CLIMEX model to predict and evaluate the global risk of C. pomonella based on historical climate data (1989-2018) and simulated future climate data (2071-2100) under the RCP4.5 scenarios. Cydia pomonella exhibited a wide distribution under both historical and future climate conditions. Climate change is predicted to expand the northern boundary of the potential distribution from approximately 60°N to 75°N. Temperature was the most dominant factor in climatic suitability for the pest. Combinations of multiple meteorological factors (relative humidity and precipitation) associated with a failure to break diapause in certain regions also affect suitability, particularly in northern South America and central Africa. Irrigation only had a slight impact on species favorability in some areas. The projections established in our study present insight into the global potential suitability of C. pomonella under climate change scenarios by the end of the 21st century. Farmers should be aware of the risk associated with the pest based on the results, which would provide guidance for quarantine agencies and trade negotiators worldwide.


Assuntos
Mudança Climática , Modelos Estatísticos , Mariposas , Dinâmica Populacional , Animais , Clima , Produtos Agrícolas/economia , Diapausa , Análise Fatorial , Frutas , Aquecimento Global , Malus , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Controle de Pragas , Pyrus , Temperatura , Árvores
7.
Arch Insect Biochem Physiol ; 107(1): e21767, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33835527

RESUMO

Mythimna separata Walker (Lepidoptera: Noctuidae) is one of the major pests that can cause severe damage to grain crops. The development of low-toxicity and high-performance botanical insecticides is becoming the focus of new pesticide research to control M. separata. Tutin, a sesquiterpene lactone compound obtained from Coriaria sinica Maxim, a native Chinese poisonous plant, has antifeedant, absorption, and stomach poisoning against a variety of pests. To understand the toxic effect of tutin on M. separata larvae, we set out to determine their antifeedant, mortality, paralysis, weight change, and to examine the spreading of M. separata hemocytes under different concentrations of tutin treatment. Tissue distribution of the immune-associated gene growth-blocking peptide (GBP) and neuroglian peptide (Nrg) was detected by reverse transcription polymerase chain reaction (PCR). Furthermore, real-time quantitative PCR was carried out to determine the expression profiles of GBP and Nrg after different concentrations of tutin stimulation. Our results revealed that tutin exhibited significant antifeedant and insecticidal activities, paralysis, weight loss to M. separata. Besides, tutin significantly influenced on the morphology of hemocytes and enhanced the expression of GBP and Nrg in M. separata.


Assuntos
Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Picrotoxina/análogos & derivados , Sesquiterpenos/farmacologia , Animais , Citocinas/efeitos dos fármacos , Citocinas/metabolismo , Hemócitos/efeitos dos fármacos , Proteínas de Insetos/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Neuropeptídeos/efeitos dos fármacos , Controle de Pragas , Picrotoxina/farmacologia
8.
Carbohydr Polym ; 259: 117749, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33673979

RESUMO

The increasing world-wide demand for food has prompted the development of efficient and environmentally friendly pesticide formulations. In this article, we have prepared CMC-g-PRSG carrier based on two compounds from natural materials carboxymethyl cellulose (CMC) and rosin (RS). The model pesticide avermectin (AVM) was encapsulated through hydrophobic interaction, and self-assembled to form nanopesticide AVM@CMC-g-PRSG with an average particle size of 167 nm. The prepared nanopesticide displays enhanced dispersibility and stability of AVM in water, and can effectively adhere to the leaves to prevent loss. The release rate of AVM encapsulated in the nanocarrier can be controlled by adjusting pH, and AVM half-life under ultraviolet radiation shows a 3-fold increase allowing control of pests for prolonged periods of time in practical applications. Biological safety tests showed that AVM@CMC-g-PRSG effectively reduces the toxicity of AVM to aquatic animals. Therefore, the cheap and degradable carrier CMC-g-PRSG can improve the effect of hydrophobic pesticides.


Assuntos
Carboximetilcelulose Sódica/química , Portadores de Fármacos/química , Resinas Vegetais/química , Animais , Liberação Controlada de Fármacos , Meia-Vida , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Ivermectina/análogos & derivados , Ivermectina/química , Ivermectina/metabolismo , Ivermectina/farmacologia , Larva/efeitos dos fármacos , Nanopartículas/química , Tamanho da Partícula , Controle de Pragas/métodos , Praguicidas/química , Praguicidas/metabolismo , Praguicidas/farmacologia , Raios Ultravioleta , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/fisiologia
9.
Sensors (Basel) ; 21(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33668820

RESUMO

The recent explosion of large volume of standard dataset of annotated images has offered promising opportunities for deep learning techniques in effective and efficient object detection applications. However, due to a huge difference of quality between these standardized dataset and practical raw data, it is still a critical problem on how to maximize utilization of deep learning techniques in practical agriculture applications. Here, we introduce a domain-specific benchmark dataset, called AgriPest, in tiny wild pest recognition and detection, providing the researchers and communities with a standard large-scale dataset of practically wild pest images and annotations, as well as evaluation procedures. During the past seven years, AgriPest captures 49.7K images of four crops containing 14 species of pests by our designed image collection equipment in the field environment. All of the images are manually annotated by agricultural experts with up to 264.7K bounding boxes of locating pests. This paper also offers a detailed analysis of AgriPest where the validation set is split into four types of scenes that are common in practical pest monitoring applications. We explore and evaluate the performance of state-of-the-art deep learning techniques over AgriPest. We believe that the scale, accuracy, and diversity of AgriPest can offer great opportunities to researchers in computer vision as well as pest monitoring applications.


Assuntos
Agricultura , Aprendizado Profundo , Benchmarking , Produtos Agrícolas , Controle de Pragas
10.
Pest Manag Sci ; 77(7): 3259-3272, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33759315

RESUMO

BACKGROUND: Agricultural pests and diseases affect grain yield and quality. In addition to the use of chemical agents, the biological control of diseases and insect pests has attracted more and more attention due to an urgent need for environmental protection. However, traditional operational methods do not integrate well with biological control technology. With the advantages of simple operation, low operating cost, high operating efficiency and wide application range, use of multirotor unmanned aerial vehicles (UAVs) in biological control is of great significance. RESULTS: An intelligent delivery system comprising an insect natural enemy (Trichogramma) capsule based on an M45 electric multirotor UAV was built to release Trichogramma ostriniae in corn fields under full autonomous mode. During operation, the M45 UAV can fly accurately in accordance with operational requirements; average deviation between the actual and planned routes was 0.24 m, the average flight speed was 9.18 m s-1 and the average altitude was 5.08 m. The effective coverage rate of natural enemies was 99.33% and the coverage redundancy was 36.75%. After delivery, an investigation into the field control effect showed an average control effect of 83.70%, which can result in effective pest control. CONCLUSION: A natural enemy carrier intelligent delivery system based on an M45 electric multirotor UAV was found to have good flight performance. In addition, natural enemies were evenly distributed, giving even coverage of the target fields. The system had a good control effect. © 2021 Society of Chemical Industry.


Assuntos
Agricultura , Himenópteros , Animais , Controle de Pragas , Tecnologia de Sensoriamento Remoto , Tecnologia
11.
Bull Entomol Res ; 111(3): 379-384, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33541447

RESUMO

The olive fruit fly, Bactrocera oleae, the most serious pest of olives, requires the endosymbiotic bacteria Candidatus Erwinia dacicola in order to complete its development in unripe green olives. Hence a better understanding of the symbiosis of Ca. E. dacicola and its insect host may lead to new strategies for reduction of B. oleae and thus minimize its economic impact on olive production. Studies of this symbiosis are hampered as the bacterium cannot be grown in vitro and the established B. oleae laboratory populations, raised on artificial diets, are devoid of this bacterium. Here, we sought to develop a method to transfer the bacteria from wild samples to laboratory populations. We tested several strategies. Cohabitation of flies from the field with the laboratory line did not result in a stable transfer of bacteria. We provided the bacteria directly to the egg and also in the food of the larvae but neither approach was successful. However, a robust method for transfer of Ca. E. dacicola from wild larvae or adults to uninfected flies by transplantation to females was established. Single female lines were set up and the bacteria were successfully transmitted for at least three generations. These results open up the possibilities to study the interaction between the symbiont and the host under controlled conditions, in view of both understanding the molecular underpinnings of an exciting, unique in nature symbiotic relationship, as well as developing novel, innovative control approaches.


Assuntos
Erwinia/crescimento & desenvolvimento , Tephritidae/microbiologia , Animais , Produtos Agrícolas , Controle de Insetos , Laboratórios , Olea , Controle de Pragas , Simbiose
12.
Science ; 371(6531): 790-791, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33602848
13.
J Econ Entomol ; 114(1): 72-81, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33558903

RESUMO

Several agroecological and integrated pest management strategies focus on landscape management to increase complexity and foster biodiversity. However, landscape complexity does not always enhance biological control and in some cases may lead to increased pest populations. We examined the prevalence of two Bracon parasitoids, Bracon cephi Gahan and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae), and their host the wheat stem sawfly Cephus cinctus Norton, a major pest of wheat. We assessed the degree of noncrop and crop host plant use and responses to landscape composition. We found no instances of parasitism by either Bracon species in our three-year, statewide winter wheat survey but found small populations of Bracon in noncrop landscapes throughout eastern and western Colorado. We used model selection to examine how local (500 m scale) and landscape (5 km scale) cover of suitable noncrop and crop habitats potentially affects abundances of Bracon and wheat stem sawfly. Our best fit model for wheat stem sawfly suggests that a decrease in noncrop cover at the landscape scale leads to an increase in wheat stem sawfly infestation. Our best fit model for Bracon parasitism suggests an increase in wheat cover at the local level results in the greatest increase in the odds of parasitism by either species of Bracon. Herbaceous cover at local and landscape scales were also significant predictors of Bracon parasitism. The results of this study suggest that pest and natural enemies respond differently to landscape composition and these responses should be evaluated before management decisions are made.


Assuntos
Himenópteros , Animais , Colorado , Ecossistema , Controle de Pragas , Estações do Ano
14.
Int J Mol Sci ; 22(4)2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33546414

RESUMO

Leucokinins (LKs) constitute a neuropeptide family first discovered in a cockroach and later identified in numerous insects and several other invertebrates. The LK receptors are only distantly related to other known receptors. Among insects, there are many examples of species where genes encoding LKs and their receptors are absent. Furthermore, genomics has revealed that LK signaling is lacking in several of the invertebrate phyla and in vertebrates. In insects, the number and complexity of LK-expressing neurons vary, from the simple pattern in the Drosophila larva where the entire CNS has 20 neurons of 3 main types, to cockroaches with about 250 neurons of many different types. Common to all studied insects is the presence or 1-3 pairs of LK-expressing neurosecretory cells in each abdominal neuromere of the ventral nerve cord, that, at least in some insects, regulate secretion in Malpighian tubules. This review summarizes the diverse functional roles of LK signaling in insects, as well as other arthropods and mollusks. These functions include regulation of ion and water homeostasis, feeding, sleep-metabolism interactions, state-dependent memory formation, as well as modulation of gustatory sensitivity and nociception. Other functions are implied by the neuronal distribution of LK, but remain to be investigated.


Assuntos
Hormônios/genética , Hormônios/metabolismo , Insetos , Invertebrados , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Animais , Regulação da Expressão Gênica , Hormônios/química , Controle de Insetos , Neurônios/metabolismo , Neuropeptídeos/química , Especificidade de Órgãos/genética , Controle de Pragas , Filogenia , Ligação Proteica , Receptores de Neuropeptídeos/metabolismo , Transdução de Sinais , Especificidade da Espécie
15.
Insect Sci ; 28(3): 611-626, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33629522

RESUMO

The evolutionary success of phytophagous insects depends on their ability to efficiently exploit plants as a source of energy for survival. Herbivorous insects largely depend on the efficiency, flexibility, and diversity of their digestive physiology and sophistication of their detoxification system to use chemically diverse host plants as food sources. The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a polyphagous pest of many commercially important crops. To elucidate the ability of this insect pest to adapt to host plant mechanisms, we evaluated the impact of primary (corn) and alternate (rice) host plants after 11 generations on gut digestive enzymatic activity and expression profiles of related genes. Results indicated that the total protease and class-specific trypsin- and chymotrypsin-like protease activity of S. frugiperda significantly differed among host plant treatments. The class-specific protease profiles greatly differed in S. frugiperda midguts upon larval exposure to different treatments with inhibitors compared with treatments without inhibitors. Similarly, the single and cumulative effects of the enzyme-specific inhibitors TLCK, TPCK, and E-64 significantly increased larval mortality and reduced larval growth/mass across different plant treatments. Furthermore, the quantitative reverse transcription polymerase chain reaction results revealed increased transcription of two trypsin (SfTry-3, SfTry-7) and one chymotrypsin gene (Sfchym-9), which indicated that they have roles in host plant adaptation. Knockdown of these genes resulted in significantly reduced mRNA expression levels of the trypsin genes. This was related to the increased mortality observed in treatments compared with the dsRED control. This result indicates possible roles of S. frugiperda gut digestive enzymes and related genes in host plant adaptation.


Assuntos
Adaptação Fisiológica/genética , Sistema Digestório/metabolismo , Endopeptidases , Herbivoria , Spodoptera , Animais , Quimotripsina/genética , Produtos Agrícolas , Digestão/efeitos dos fármacos , Sistema Digestório/efeitos dos fármacos , Endopeptidases/efeitos dos fármacos , Endopeptidases/genética , Endopeptidases/metabolismo , Genes de Insetos , Herbivoria/efeitos dos fármacos , Herbivoria/genética , Herbivoria/fisiologia , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Oryza , Controle de Pragas , Inibidores de Proteases/farmacologia , Interferência de RNA , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/metabolismo , Transcriptoma , Tripsina/genética , Zea mays
16.
Pest Manag Sci ; 77(7): 3126-3134, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33638310

RESUMO

BACKGROUND: Pest management professionals use anticoagulant rodenticides, usually placed in tamper-resistant bait stations, to control commensal rodents, but significant concerns remain about exposure of nontarget species, especially at the urban-wildland interface. We deployed digital cameras to monitor use of bait stations placed in 90 residential yards across Orange County, California, USA. Two bait stations, supplied with nontoxic bait, were monitored in each yard for approximately 30 consecutive days during two camera-trapping sessions between December 2017 and March 2019. One station was placed on the ground, while the other was elevated 1-1.5 m to determine if elevating stations could reduce nontarget exposure. RESULTS: Black rats (Rattus rattus L.) were present at 80% of sites, with mean activity ranging from 0 to 9.6 h each night. There were no significant differences between elevated and ground stations in the time to discovery, time to bait station entry, or nightly activity of rats. Rats discovered bait stations more quickly, and mean nightly activity was greater, in yards where rats were detected more frequently. Although native rodents visited and entered bait stations occasionally, they were relatively rare among our sites (13.3%), and were detected five times less often at elevated stations compared to those on the ground. Yards visited by these rodents were significantly nearer to areas of green open space and natural vegetation, and tended to have no significant barriers to entry, e.g. solid fences or walls. CONCLUSIONS: By elevating bait stations and avoiding placing rodenticides in yards that are likely to be visited by wildlife, pest management professionals may be able to reduce the risk of nontarget exposure, including secondary poisoning of predators and scavengers, while still providing effective control of commensal pests. © 2021 Society of Chemical Industry.


Assuntos
Rodenticidas , Animais , Anticoagulantes , Controle de Pragas , Ratos , Roedores , Rodenticidas/toxicidade , Simbiose
17.
J Econ Entomol ; 114(2): 970-978, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33625491

RESUMO

Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.


Assuntos
Hemípteros , Animais , Comportamento Alimentar , Controle de Pragas , Crescimento Demográfico , Soja/genética
18.
Pest Manag Sci ; 77(6): 2785-2794, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33522130

RESUMO

BACKGROUND: The pollen beetle (Brassicogethes aeneus) is the most abundant pest of oilseed rape in spring and is potentially one of the most damaging. Adults feed on the pollen within closed flower buds and the damage leads to bud abscission, resulting in podless stalks and yield reduction. Several methods are currently used to monitor the pressure of this insect, such as counting the numbers of adults on the plants, quantifying the number of buds damaged by the insect before flowering or counting the number of podless stalks before harvest. We conducted experiments to evaluate the robustness of these sampling methods and compared their results. We also describe how pollen beetles damage the plants to understand the limitations of methods based on damage estimation. RESULTS: Methods based on adult abundance lack robustness. We observed that most of the damage to buds is caused by pollen beetles feeding on small buds (< 3 mm), and that this damage can be quantified later in the season, indicating that methods based on the count of podless stalks are robust. Different methods gave consistent results and quantification of the pressure on the primary raceme can be a good proxy for pressure on the whole plant. CONCLUSIONS: Standardised methods for assessment of pollen beetle pressure will enable comparison of pest management strategies between different studies and facilitate the development of alternative control strategies for this pest. © 2021 Rothamsted Research. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Brassica napus , Besouros , Animais , Controle de Pragas , Pólen , Estações do Ano
20.
Environ Sci Pollut Res Int ; 28(21): 26628-26642, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33491144

RESUMO

The aim of the conducted study was to characterize the attitudes and practices of Polish farmers in the area of performing chemical plant protection treatments. A particular attention was paid to identifying the relationship between the direction of changes in the volume of chemical plant protection product consumption and selected attributes of farms. The main time range of the analyses covered the period of 2013-2017. Statistical data and results of representative surveys carried out on a sample of 1101 farms in Poland were used in the research process. Due to the large number of variants of the analysed variables, a multiple correspondence analysis was used, which made it possible to determine the correlation between the examined features (direction of changes in pesticide use relative to the farm area, economic size of the farm and location of the farm). Statistical analysis showed the existence of strong relationships between the physical (1) and economic (2) size of farms and the direction of changes in pesticide consumption ((1) φ2 = 0.0907; (2) φ2 = 0.1141)). According to empirical studies, the reduction of pesticide consumption took place mainly on the smallest farms. The implementation of the integrated plant protection directive has not resulted in significant changes in the form of reduced pesticide use in large-scale field crops. This raises the need to modify the strategy and model of crop protection in large-scale field crops in Poland.


Assuntos
Praguicidas , Agricultura , Fazendeiros , Humanos , Controle de Pragas , Polônia
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