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1.
Chemosphere ; 287(Pt 2): 132017, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34509008

RESUMO

The fan nozzle is widely used in the process of pest control in agriculture and forestry. The spray angle of the nozzle is an important characterization parameter in the atomization of liquids. The spray angle of the nozzle is an important characterizing parameter in the liquid atomization process. It affects the flow field at the exit of the nozzle, thereby affecting the size and velocity of the droplets, and further affecting the deposition effect of the droplets on the crop. Therefore, its research is of great significance for improving the deposition of liquid on plants and controlling pests and related diseases. Based on the classical theory of predecessors and considering the parameters of the flat fan nozzle, we further optimized the theory at the structural level by means of a simulation test and built a spray angle theoretical model taking into account the parameters of the inner chamber of the nozzle. We arrived at the following conclusions: (1) the average error of the spray angle measured by the simulation test and the actual test spray angle was 2.95%, the maximum spray angle deviation value was 2.81°, and the result proves that the simulation test parameter setting is accurate; and (2) the average error between the actual measured value and the theoretical model calculation value was 3.56%, the maximum spray angle deviation was 4°, through the actual test comparison, and the spray angle error of the theoretical model was within the allowable error range of industry production. It was proved that the model could effectively reflect the changing law of spray angle of the flat fan nozzle.


Assuntos
Agricultura , Controle de Pragas , Modelos Teóricos , Tamanho da Partícula , Fenômenos Físicos
2.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34718645

RESUMO

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.


Assuntos
Apoptose/efeitos da radiação , Raios gama , Expressão Gênica/efeitos da radiação , Tephritidae/efeitos da radiação , Animais , Antioxidantes/metabolismo , Antioxidantes/efeitos da radiação , Apoptose/genética , Catalase/metabolismo , Catalase/efeitos da radiação , Radioisótopos de Cobalto/farmacologia , Controle de Insetos/métodos , Proteínas de Insetos/metabolismo , Proteínas de Insetos/efeitos da radiação , Larva/genética , Larva/metabolismo , Larva/fisiologia , Larva/efeitos da radiação , Longevidade/efeitos da radiação , Malondialdeído/metabolismo , Malondialdeído/efeitos da radiação , Peroxidase/metabolismo , Peroxidase/efeitos da radiação , Controle de Pragas/métodos , Pupa/genética , Pupa/metabolismo , Pupa/fisiologia , Pupa/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/efeitos da radiação , Tephritidae/genética , Tephritidae/metabolismo , Tephritidae/fisiologia
3.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34605547

RESUMO

Paracoccus marginatus (Hemiptera: Pseudococcidae), known as the papaya mealybug, could cause considerable yield loss of several plants. To date, there is no molecular-based study of P. marginatus. Fatty acyl-CoA reductases (FARs) are key enzymes involved in wax synthesis. In the present study, we cloned and characterized coding sequences (CDS) of two FAR genes from P. marginatus. The results showed that PmFAR1 and PmFAR2 CDS were 1,590 and 1,497 bp in length, respectively, and sequence analysis indicated that these two genes both had the conservative motifs belonging to FAR_C superfamily. Furthermore, seven candidate reference genes were analyzed for their expression stability by using common algorithms including comparative ΔCq method, geNorm, NormFinder, BestKeeper, and RefFinder. Eventually, ß-actin and GAPDH were the best reference genes in evaluating the expression of those two FAR genes. We found that PmFAR1 and PmFAR2 showed distinct expression patterns in different life stages. Moreover, the transcription of PmFAR1 and PmFAR2 in P. marginatus fed on resistant cassava cultivars was significantly lower compared with those fed on susceptible ones, indicating the potential function of FAR genes in cassava resistance to P. marginatus. The present study might help in better understanding the molecular mechanism of cassava resistance to mealybug.


Assuntos
Aldeído Oxirredutases/genética , Hemípteros/genética , Animais , Perfilação da Expressão Gênica , Herbivoria/genética , Manihot , Controle de Pragas , Defesa das Plantas contra Herbivoria
4.
Arch Insect Biochem Physiol ; 108(3): e21845, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34605064

RESUMO

With the wide cultivation of transgenic plants throughout the world and the rising risk of resistance to Bacillus thuringiensis crystal (Cry) toxins, it is essential to design an adaptive resistance management strategy for continued use. Neuropeptide F (NPF) of insects has proven to be valuable for the production of novel-type transgenic plants via its important role in the control of feeding behavior. In this study, the gene encoding NPF was cloned from the diamondback moth, Plutella xylostella, an important agricultural pest. Real-time quantitative reverse transcription-polymerase chain reaction and in situ hybridization showed a relatively high expression of P. xylostella-npf (P. x-npf) in endocrine cells of the midgut of fourth instar larvae, and it was found to participate in P. xylostella feeding behavior and Cry1Ac-induced feeding inhibition. Prokaryotic expression and purification provided structure unfolded P. x-npf from inclusion bodies for diet surface overlay bioassays and the results demonstrated a significant synergistic effect of P. x-npf on Cry1Ac toxicity by increasing intake of noxious food which contains Cry toxins, especially quick death at an early stage of feeding. Our findings provided a potential new way to efficiently control pests by increasing intake of lower dose Cry toxins and a novel hint for the complex Cry toxin mechanism.


Assuntos
Toxinas de Bacillus thuringiensis , Endotoxinas , Proteínas Hemolisinas , Mariposas , Neuropeptídeos , Animais , Toxinas de Bacillus thuringiensis/farmacologia , Endotoxinas/farmacologia , Comportamento Alimentar/fisiologia , Expressão Gênica , Genes de Insetos , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Proteínas de Insetos/farmacologia , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/metabolismo , Mariposas/fisiologia , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Neuropeptídeos/farmacologia , Controle de Pragas/métodos
5.
Naturwissenschaften ; 108(6): 47, 2021 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-34601632

RESUMO

Since of the first sex pheromone and the adoption of pheromone in pest management, the global pheromone market size has grown to reach USD 2.4 billion per year in 2019. This has enabled the development of environmentally friendly approaches that significantly reduce the application of pesticides. Recently, there have been reports of the failure of various commercial codlemone: (E,E)-8,10-dodecadien-1-ol formulations used for monitoring the apple pest codling moth, Cydia pomonella (L.). This work was initiated to investigate factors behind the lack of efficacy of codlemone lure in the Northern Hemisphere (Germany) and Southern Hemisphere (New Zealand). We hypothesised that the observed failure could be due to two main factors: (a) a shift in the response of male codling moth to codlemone and (b) degradation of codlemone under field conditions that renders the lure less attractive. Field trial tests of various doses and blends containing minor pheromone compounds suggested no change in response of male codling moth. The addition of an antioxidant and a UV stabiliser to codlemone resulted in a significant increase in the number of males caught in Germany, but not in New Zealand. Mean maximum temperatures during the growing season since 2004 indicate a 3 °C increase to 35 °C in Germany, but just a 1.5 °C rise to 30 °C in New Zealand. Chemical analysis of the lures used in the field trials in Germany and New Zealand indicated more degradation products and reduced half-life of the lures in Germany compared with those in New Zealand. Heating codlemone lures to 32 °C significantly reduced the number of males caught in traps and increased the isomeric and chemical impurities of codlemone compared with unheated lures. Our data provide the first evidence that climate change affects pheromone molecule stability, thus reducing its biological efficacy. Our finding suggests that climate change could be a general problem for chemical communication and, therefore, could affect the integrity of natural ecosystems.


Assuntos
Mariposas , Atrativos Sexuais , Animais , Mudança Climática , Ecossistema , Masculino , Controle de Pragas , Feromônios/farmacologia , Atrativos Sexuais/farmacologia
6.
PLoS One ; 16(10): e0258864, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34710164

RESUMO

Pesticides are the leading defence against pests, but their unsafe use reciprocates the pesticide residues in highly susceptible food and is becoming a serious risk for human health. In this study, mint extract and riboflavin were tested as photosensitisers in combination with light irradiation of different frequencies, employed for various time intervals to improve the photo-degradation of deltamethrin (DM) and lambda cyhalothrin (λ-CHT) in cauliflower. Different source of light was studied, either in ultraviolet range (UV-C, 254 nm or UV-A, 320-380 nm) or sunlight simulator (> 380-800 nm). The degradation of the pesticides varied depending on the type of photosensitiser and light source. Photo-degradation of the DM and λ-CHT was enhanced by applying the mint extracts and riboflavin and a more significant degradation was achieved with UV-C than with either UV-A or sunlight, reaching a maximum decrement of the concentration by 67-76%. The light treatments did not significantly affect the in-vitro antioxidant activity of the natural antioxidants in cauliflower. A calculated dietary risk assessment revealed that obvious dietary health hazards of DM and λ-CHT pesticides when sprayed on cauliflower for pest control. The use of green chemical photosensitisers (mint extract and riboflavin) in combination with UV light irradiation represents a novel, sustainable, and safe approach to pesticide reduction in produce.


Assuntos
Nitrilas/química , Resíduos de Praguicidas/análise , Praguicidas/química , Fármacos Fotossensibilizantes , Piretrinas/química , Humanos , Controle de Pragas , Transtornos de Fotossensibilidade
7.
PLoS One ; 16(10): e0258610, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34648583

RESUMO

Leptocybe invasa Fisher et LaSalle is a global invasive pest that seriously damages Eucalyptus plants. Studying the genetic diversity, genetic structure and introgression hybridization of L. invasa in China is of great significance for clarifying the breeding strategy, future invasion and diffusion trends of L. invasa in China and developing scientific prevention and control measures. Genetic diversity and phylogenetic analyses of 320 L. invasa female adults from 14 geographic populations in China were conducted using 10 polymorphic microsatellite loci (SSRs) and mitochondrial DNA cytochrome oxidase I gene sequences (COIs). (1) The Bayesian phylogenetic tree and haplotype network diagram showed that only haplotype Hap3 existed in L. invasa lineage B in China, while haplotypes Hap1 and Hap2 existed in lineage A, among which haplotype Hap2 was found for the first time. The nucleotide and haplotype diversities of lineage A were higher than those of lineage B. (2) The SSR genetic diversity of the Wuzhou Guangxi, Ganzhou Jiangxi and Panzhihua Sichuan populations was higher than that of the other 11 populations, and the SSR genetic diversity of lineage A was higher than that of lineage B. (3) The AMOVA analysis of mitochondrial COI data showed that 75.55% of the variation was among populations, and 99.86% of the variation was between lineages, while the AMOVA analysis of nuclear SSR data showed that 35.26% of the variation was among populations, and 47.04% of the variation was between lineages. There were obvious differences in the sources of variation between the COI and SSR data. (4) The optimal K value of COI and SSR data in structure analysis was 2, and PCoA analysis also divided the dataset into two obvious categories. The UPMGA phylogenetic tree based on SSR data clustered 14 geographic species into two groups. The results of genetic structure analysis supported the existence of two lineages, A and B, in China. (5) Structural analysis showed that there was obvious introgressive hybridization in Wuzhou Guangxi, Ganzhou Jiangxi, Panzhihua Sichuan and other populations. These results suggest that lineage introgressive hybridization has occurred in the L. invasa population in China. The introgressive hybridization degree and genetic diversity of lineage A are obviously higher than those of lineage B. Lineage introgressive hybridization may be the driving force for further L. invasa invasion and diffusion in China in the future.


Assuntos
Himenópteros/classificação , Repetições de Microssatélites , Oxirredutases/genética , Animais , Teorema de Bayes , China , Feminino , Introgressão Genética , Variação Genética , Himenópteros/genética , Proteínas de Insetos/genética , Espécies Introduzidas , Controle de Pragas , Filogenia
8.
Math Biosci Eng ; 18(5): 5364-5391, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34517492

RESUMO

We develop a mathematical model, based on a system of ordinary differential equations, to the upshot of farming alertness in crop pest administration, bearing in mind plant biomass, pest, and level of control. Main qualitative analysis of the proposed mathematical model, akin to both pest-free and coexistence equilibrium points and stability analysis, is investigated. We show that all solutions of the model are positive and bounded with initial conditions in a certain significant set. The local stability of pest-free and coexistence equilibria is shown using the Routh-Hurwitz criterion. Moreover, we prove that when a threshold value is less than one, then the pest-free equilibrium is locally asymptotically stable. To get optimum interventions for crop pests, that is, to decrease the number of pests in the crop field, we apply optimal control theory and find the corresponding optimal controls. We establish existence of optimal controls and characterize them using Pontryagin's minimum principle. Finally, we make use of numerical simulations to illustrate the theoretical analysis of the proposed model, with and without control measures.


Assuntos
Agricultura , Modelos Biológicos , Simulação por Computador , Modelos Teóricos , Controle de Pragas
9.
Comput Intell Neurosci ; 2021: 5436729, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34512742

RESUMO

The prevention and control of navel orange pests and diseases is an important measure to ensure the yield of navel oranges. Aiming at the problems of slow speed, strong subjectivity, high requirements for professional knowledge required, and high identification costs in the identification methods of navel orange pests and diseases, this paper proposes a method based on DenseNet and attention. The power mechanism fusion (DCPSNET) identification method of navel orange diseases and pests improves the traditional deep dense network DenseNet model to realize accurate and efficient identification of navel orange diseases and pests. Due to the difficulty in collecting data of navel orange pests and diseases, this article uses image enhancement technology to expand. The experimental results show that, in the case of small samples, compared with the traditional model, the DCPSNET model can accurately identify different types of navel orange diseases and pests images and the accuracy of identifying six types of navel orange diseases and pests on the test set is as high as 96.90%. The method proposed in this paper has high recognition accuracy, realizes the intelligent recognition of navel orange diseases and pests, and also provides a way for high-precision recognition of small sample data sets.


Assuntos
Citrus sinensis , Controle de Pragas
10.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536080

RESUMO

Varroa destructor is among the greatest biological threats to western honey bee (Apis mellifera L.) health worldwide. Beekeepers routinely use chemical treatments to control this parasite, though overuse and mismanagement of these treatments have led to widespread resistance in Varroa populations. Integrated Pest Management (IPM) is an ecologically based, sustainable approach to pest management that relies on a combination of control tactics that minimize environmental impacts. Herein, we provide an in-depth review of the components of IPM in a Varroa control context. These include determining economic thresholds for the mite, identification of and monitoring for Varroa, prevention strategies, and risk conscious treatments. Furthermore, we provide a detailed review of cultural, mechanical, biological, and chemical control strategies, both longstanding and emerging, used against Varroa globally. For each control type, we describe all available treatments, their efficacies against Varroa as described in the primary scientific literature, and the obstacles to their adoption. Unfortunately, reliable IPM protocols do not exist for Varroa due to the complex biology of the mite and strong reliance on chemical control by beekeepers. To encourage beekeeper adoption, a successful IPM approach to Varroa control in managed colonies must be an improvement over conventional control methods and include cost-effective treatments that can be employed readily by beekeepers. It is our intention to provide the most thorough review of Varroa control options available, ultimately framing our discussion within the context of IPM. We hope this article is a call-to-arms against the most damaging pest managed honey bee colonies face worldwide.


Assuntos
Criação de Abelhas/métodos , Abelhas/parasitologia , Controle de Pragas/métodos , Varroidae , Acaricidas/farmacologia , Animais , Interações Hospedeiro-Parasita , Infestações por Ácaros/tratamento farmacológico , Infestações por Ácaros/prevenção & controle , Infestações por Ácaros/veterinária , Varroidae/efeitos dos fármacos , Varroidae/parasitologia , Varroidae/patogenicidade
11.
Arch Insect Biochem Physiol ; 108(3): e21840, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34569086

RESUMO

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), the cotton bollworm, is a destructive pest which is famous for its resistance to a variety of insecticides. RNA interference is a posttranscriptional gene silencing mechanism that has become a popular tool to control insect pests, triggered by double-stranded RNAs (dsRNAs). The effect of ingestion and injection delivery methods of dsRNA related to some protease genes including Trypsin (Ha-TRY39 and Ha-TRY96), Chymotrypsin (Ha-CHY), and Cathepsin L (Ha-CAT) on growth and development of H. armigera was investigated in this study. All protease genes encoded full ORFs and were expressed in all H. armigera larvae stages and tissues. In both injection and feeding bioassays, Ha-RNAi CHY's performance outperformed that of other protease genes. CHY enzyme activity in the midgut of larvae was significantly reduced after treatment with ds-HaCHY. Oral administration of ds-CHY also resulted in significant mortality of H. armigera larvae. However, because of the high RNase activity in the midgut lumen of lepidoptera, a large amount of dsRNA was needed to effectively kill instars of H. armigera. To reduce dsRNA degradation, bacterial expression and dsRNA formulation were used. After oral administration, it was toxic to H. armigera larvae. Before oral administration, bacterial cells were sonicated to increase dsRNA release. The RNA interference efficiency of sonicated bacteria was significantly increased, resulting in higher larval mortality when administered orally. All of these findings point to Ha-CHY as a new candidate for developing an effective dsRNA-based pesticide for H. armigera control.


Assuntos
Mariposas , Peptídeo Hidrolases , RNA de Cadeia Dupla/farmacologia , Animais , Bactérias/genética , Catepsinas/efeitos dos fármacos , Catepsinas/genética , Quimotripsina/efeitos dos fármacos , Quimotripsina/genética , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Mortalidade , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Organismos Geneticamente Modificados , Peptídeo Hidrolases/efeitos dos fármacos , Peptídeo Hidrolases/genética , Controle de Pragas/métodos , Interferência de RNA , RNA de Cadeia Dupla/biossíntese , RNA de Cadeia Dupla/metabolismo , Tripsina/efeitos dos fármacos , Tripsina/genética
12.
Arch Insect Biochem Physiol ; 108(3): e21842, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34499777

RESUMO

Glyphodes pyloalis Walker has become one of the most significant mulberry pests, and it has caused serious economic losses in major mulberry growing regions in China. Peptidoglycan recognition proteins (PGRPs) are responsible for initiating and regulating immune signalling pathways in insects. However, their roles responding to chemical pesticides is still less known. This study aimed to investigate the possible detoxication function of GpPGRP-S2 and GpPGRP-S3 in G. pyloalis in response to chlorfenapyr and phoxim. The chlorfenapyr and phoxim treatment significantly induced the expression level of GpPGRP-S3 at 48 h. In addition, the expression levels of GpPGRP-S2 and GpPGRP-S3 in the chlorfenapyr/phoxim treatment group were significantly higher in midgut than those in the control group at 48 h. The results of the survival experiment showed that silencing either GpPGRP-S2 or GpPGRP-S3 would not influence the survival rate of G. pyloalis which treated with phoxim, however, silencing GpPGRP-S2 or GpPGRP-S3 would cause G. pyloalis to be more easily killed by chlorfenapyr. The expression of carboxylesterase GpCXE1 was significantly induced by chlorfenapyr/phoxim treatment, while it was suppressed once silenced GpPGRP-S2 followed with chlorfenapyr treatment or silenced GpPGRP-S3 followed with phoxim treatment. These results might suggest that under the chlorfenapyr/phoxim treatment condition, the connection between GpPGRPs and detoxification genes in insect was induced to maintain physiological homeostasis; and these results may further enrich the mechanisms of insects challenged by insecticides.


Assuntos
Proteínas de Transporte , Inseticidas , Mariposas , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Inseticidas/metabolismo , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/metabolismo , Compostos Organotiofosforados/metabolismo , Compostos Organotiofosforados/farmacologia , Controle de Pragas/métodos , Piretrinas/metabolismo , Piretrinas/farmacologia
13.
PLoS One ; 16(9): e0256719, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34529677

RESUMO

By adopting the 2009 "pesticide package," the EU proposed a common approach to limiting the harmful effects of pesticides, promoting Integrated Pest Management, and the progressive replacement of the most dangerous pesticides with low-risk alternatives through a comprehensive but flexible framework for all EU Member States. Each EU Member State had to develop a National Action Plan that would propose measures to achieve the package's goals. Nevertheless, the choice of actions and indicators remained to be established at the national level. A series of recent evaluations of how Directive 2009/128/EC of the European Parliament and the Council on the Sustainable Use of Pesticides Directive (SUD), a central piece of the "pesticide package," was implemented showed limited success in achieving its goals. Aiming to explain these failures, we compare the National Action Plans eight EU Member States adopted after the SUD. We assess the degree to which the countries' proposed measures and indicators would achieve the Directive's three overarching objectives (reduce risks and impact; promote Integrated Pest Management; promote approaches and techniques to reduce reliance on pesticides). We develop the comparative analysis along three dimensions: the promotion of measures to achieve SUD's three goals; the evolution of the pre-and post-Directive action plans of some of the old EU Member States; and the differences between old and the new EU Member States. The comparison along ten variables shows that the SUD had a minimal effect in homogenizing different states' approaches to develop their National Action Plans to systematically treat problems, propose measures, and timetables for implementation and indicators. Given that the overall effect in generating a common EU approach to raise the sustainability of pesticide use and agriculture, in general, was still limited, as no common measures, indicators, or process to planning were identified, we discuss some suggestions to improve the situation.


Assuntos
Agricultura/métodos , Programas Governamentais/métodos , Controle de Pragas/métodos , Praguicidas/análise , União Europeia
14.
J Insect Sci ; 21(4)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415303

RESUMO

The gut microbiota of insects usually plays an important role in the development and reproduction of their hosts. The fecundity of Henosepilachna vigintioctopunctata (Fabricius) varies greatly when they develop on different host plants. Whether and how the gut microbiota regulates the fecundity of H. vigintioctopunctata was unknown. To address this question, we used 16S rRNA sequencing to analyze the gut microbiomes of H. vigintioctopunctata adults fed on two host plant species (Solanum nigrum and Solanum melongena) and one artificial diet. The development of the ovaries and testes was also examined. Our results revealed that the diversity and abundance of gut microorganisms varied significantly in insects reared on different diets. The gut microbiota of H. vigintioctopunctata raised on the two host plants was similar, with Proteobacteria being the dominant phylum in both groups, whereas Firmicutes was the dominant phylum in the group reared on the artificial diet. The predominant microbiota in the S. nigrum group were Acinetobacter soli and Acinetobacter ursingii (Acinetobacter, Moraxellaceae); Moraxella osloensis (Enhydrobacter, Moraxellaceae); and Empedobacter brevis (Empedobacter, Weeksellaceae). The microbiota in this group are associated with high lipid metabolism. In addition, the beetles' ovaries and testes were more highly developed in the S. nigrum group than in the other two groups. These findings provide valuable information for elucidating the complex roles the gut microbiota play in the fecundity of H. vigintioctopunctata, and may also contribute to developing future novel control strategies involving this economically important pest.


Assuntos
Besouros , Fertilidade , Microbioma Gastrointestinal/genética , Animais , Bactérias/isolamento & purificação , Besouros/microbiologia , Besouros/fisiologia , DNA Bacteriano , Dieta , Feminino , Metabolismo dos Lipídeos , Masculino , Metagenômica , Ovário/crescimento & desenvolvimento , Controle de Pragas , RNA Ribossômico 16S , Testículo/crescimento & desenvolvimento
15.
ACS Appl Mater Interfaces ; 13(33): 39066-39075, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387079

RESUMO

A controlled release formulation based on silica microcapsules is an ideal selection to improve both the effective utilization and duration of pesticides to decrease ecological damage. Herein, a simple and green method for preparing double-shelled microcapsules was developed using a newly prepared quaternary ammonium ionic liquid (IL) as the functional additive to entrap avermectin (Ave) in mesoporous silica nanospheres (MSNs) and tannic acid-Cu (TA-Cu) complex as the sealing agent to form the core-shell structure (Ave-IL@MSN@TA-Cu). The obtained microcapsules with an average size of 538 nm had pH-responsive release property and good stability in soil. The half-life of microcapsules (34.66 days) was 3 times that of Ave emulsifiable concentrate (EC) (11.55 days) in a test soil, which illustrated that microcapsules could protect Ave from rapid degradation by microorganisms by releasing TA, copper, and quaternary ammonium in the soil. Ave-IL@MSN@TA-Cu microcapsules had better nematicidal activity and antibacterial activity than Ave EC due to the synergistic effect of Ave, IL, and copper incorporated in the microcapsules. Pot experiments showed that the control efficacy of microcapsules was 87.10% against Meloidogyne incognita, which is better than that of Ave EC (41.94%) at the concentration of 1.0 mg/plant by the root-irrigation method after 60 days of treatment owing to the extended duration of Ave in microcapsules. The simple and green method for the preparation of double-shelled microcapsules based on natural quaternary ammonium IL would have tremendous potential for the extensive development of controlled release pesticide formulations.


Assuntos
Cápsulas/química , Preparações de Ação Retardada/química , Controle de Pragas/métodos , Praguicidas/química , Dióxido de Silício/química , Tylenchoidea/efeitos dos fármacos , Animais , Complexos de Coordenação/química , Cobre/química , Preparações de Ação Retardada/farmacologia , Composição de Medicamentos , Liberação Controlada de Fármacos , Química Verde , Concentração de Íons de Hidrogênio , Líquidos Iônicos/química , Ivermectina/análogos & derivados , Ivermectina/química , Ivermectina/farmacologia , Praguicidas/farmacologia , Porosidade , Compostos de Amônio Quaternário/química , Solubilidade , Taninos/química , Fatores de Tempo
16.
Avian Dis ; 65(2): 287-294, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34412460

RESUMO

As part of a 2 yr disease surveillance project of small poultry flocks, owners of birds submitted for postmortem examination to the Animal Health Laboratory were asked to complete a questionnaire designed to gather information on the characteristics of the flock and its environment, how the flock was managed, and biosecurity measures used. A total of 153 unique questionnaires were received. Personal consumption of meat or eggs was the most common reason for owning a small flock (69.3%). Almost all owners (97.4%) reported having chickens on their property, while 21.6% had waterfowl, 15.7% had turkeys, and 15.7% had game birds. Nearly 70% (69.9%) of the flocks had some degree of outdoor access. For those with indoor access, the most common bedding material provided was soft wood shavings (70.2%). Kitchen waste or leftovers were offered to 65.3% of flocks, and well water was the most common source of drinking water (80.6%). For flocks with indoor access, dedicated shoes and clothes were used when entering or cleaning the coop by fewer than half of owners, and shoes were rarely disinfected before or after contact with the flock. Most owners (93.8%) reported washing their hands after contact with their birds, although only 48.3% reported washing their hands before contact. Among owners who sourced birds from a hatchery, only 36.8% indicated that the birds had been vaccinated, and 21.1% were unsure if vaccines had been administered. Among owners using medication (60.5%), the use of antibiotics was common (60.9%). Overall, questionnaire responses describe a wide range of husbandry and biosecurity practices, often suboptimal, and point out the need for educational material for Ontario small flock owners.


Assuntos
Criação de Animais Domésticos/métodos , Doenças das Aves Domésticas/epidemiologia , Aves Domésticas , Ração Animal , Criação de Animais Domésticos/normas , Criação de Animais Domésticos/estatística & dados numéricos , Animais , Estudos Transversais , Água Potável , Desinfecção das Mãos , Abrigo para Animais , Ontário/epidemiologia , Controle de Pragas/métodos , Aves Domésticas/classificação , Doenças das Aves Domésticas/patologia , Sistema de Registros , Medidas de Segurança , Inquéritos e Questionários , Vacinação/veterinária
17.
Sci Total Environ ; 799: 149381, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34358747

RESUMO

Explaining the reasons for the high honey bee (Apis mellifera) colony loss rate in recent years has become a top global research priority in apicultural and agricultural sciences. Although there are indications of the role played by beekeeping management practices on honey bee health, very little information is currently available. Our study aimed to characterize the beekeeping management practices carried out in Belgium, and to determine the relationship between beekeeping management practices and colony losses. Variables obtained from face-to-face questioning of a representative randomized and stratified sample of Belgian beekeepers (n = 186) were integrated into a logistic regression model (univariate and multivariate) and correlated to the declared colony loss rates to identify risk and protective indicators. We used a classification tree analysis to validate the results. We present evidence of a relationship between poor beekeeping management practices and colony losses. The main factors protecting honey bee colonies are the aptitude of the beekeeper to change his management practices, the hive type, the equipment origin and hygiene, wintering in proper conditions (the use of divider boards, i.e. board blocks or space fillers off part of the hive body), the colony strength estimation before wintering, winter monitoring, and last but not least, appropriate integrated pest management. Proper estimation of the Varroa infestation level should be performed prior to treatment. The consequences of poor beekeeping practices on honey bee health can be addressed by proper training of beekeepers. An online tool was developed and published for beekeepers allowing them to evaluate the effect of their management practices on colony health.


Assuntos
Criação de Abelhas , Varroidae , Animais , Abelhas , Bélgica , Controle de Pragas , Estações do Ano
18.
PLoS One ; 16(8): e0255372, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34383810

RESUMO

This study was conducted in Farta district, south Gondar from 2019 to 2020 cropping years to identify rodent pest species and estimate damage caused on barley crops. Four independent barley crop fields (40 x 40 m each) were sampled randomly to estimate the loss. Two were located near Alemsaga Priority State Forest and the other two were away from the forest. Four (2 x 2 m) rodent exclusion plots were established at 10 m interval as control units in each selected experimental barley fields using fine wire mesh. Rodent pest species were collected using both Sherman and snap traps throughout the different crop growing stages. The damaged and undamaged barley tillers by pest rodents were counted on five 1 x 1 m randomly sampled quadrats for each selected experimental fields. Variations on pest rodent population between cropping years and sites were analyzed using Chi square test. The mean crop damages between cropping years and experimental field sites were analyzed using two way ANOVA. Arvicanthis abyssinicus, Mastomys natalensis, Arvicanthis dembeensis, Mus musculus, Lophuromys simensis, Tachyoryctes splendens and Hystrix cristata were identified as pest rodents in the study area. A total of 968 individual rodents (427 in 2019 and 541 in 2020) were trapped during the study period. There was a statistical variation (χ2 = 13.42, df = 1 and P<0.05) between trapped individuals of the two successive years. The crop fields near the forest were more vulnerable than away from the forest during both cropping years. Statistical variations was observed on mean crop losses between cropping years and experimental barley crop sites. The highest crop damage was seen at maturity stage and the lowest during sowing in all experimental plots and cropping years. The percentage of barley yield loss due to rodent pests was 21.7 kg ha-1. The monetary value of this yield loss was equivalent to 4875 Birr (121.9 US$ h-1). Alemsaga Forest as shelter and conservation strategies like free of farmland from livestock and terracing for soil conservation have great role for the high rodent pest populations in the study area. Field sanitation, trapping and using restricted rodenticides like zinc phosphide are the possible recommendation to local farmers against rodent pests.


Assuntos
Produção Agrícola/métodos , Hordeum/crescimento & desenvolvimento , Roedores/fisiologia , Animais , Produção Agrícola/economia , Produtos Agrícolas/economia , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/parasitologia , Demografia , Etiópia , Fazendas , Florestas , Herbivoria , Hordeum/parasitologia , Controle de Pragas , Roedores/classificação
19.
Arch Insect Biochem Physiol ; 108(1): e21833, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34288091

RESUMO

The homeobox family is a large and diverse superclass of genes, many of which act as transcription factors that play important roles in tissue differentiation and embryogenesis in animals. The brown planthopper (BPH), Nilaparvata lugens, is the most destructive pest of rice in Asia, and high fecundity contributes significantly to its ecological success in natural and agricultural habits. Here, we identified 94 homeobox genes in BPH, which could be divided into 75 gene families and 9 classes. This number is comparable to the number of homeobox genes found in the honeybee Apis mellifera, but is slightly less than in Drosophila or the red flour beetle Tribolium castaneum. A spatio-temporal analysis indicated that most BPH homeobox genes were expressed in a development and tissue-specific manner, of which 21 genes were highly expressed in ovaries. RNA interference (RNAi)-mediated functional assay showed that 22 homeobox genes were important for nymph development and the nymph to adult transition, whereas 67 genes were dispensable during this process. Fecundity assay showed that knockdown of 13 ovary-biased genes (zfh1, schlank, abd-A, Lim3_2, Lmxb, Prop, ap_1, Not, lab, Hmx, vis, Pknox, and C15) led to the reproductive defect. This is the first comprehensive investigation into homeobox genes in a hemipteran insect and thus helps us to understand the functional significance of homeobox genes in insect reproduction.


Assuntos
Fertilidade/genética , Genes Homeobox , Hemípteros/genética , Animais , Perfilação da Expressão Gênica/métodos , Genes de Insetos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Ninfa/genética , Controle de Pragas , Interferência de RNA , Reprodução/genética
20.
Pest Manag Sci ; 77(11): 4980-4992, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34216079

RESUMO

BACKGROUND: Integrating unmanned aerial vehicles (UAV) as a new method of pesticide application into existing commercial crop protection systems requires extensive research and comparison to conventional, proven application technology. Pest control expressed as efficacy against target pests, and spray quality expressed as coverage and chemical residue are three key criteria. We investigated and compared these quantitative parameters between a multi-rotor UAV and conventional piloted airplanes in two commercial alfalfa production systems. RESULTS: Effective and equivalent control of leaf-feeding insect pests was achieved by both methods of aerial application when delivering chlorantraniliprole at the same labeled use rate in different spray volumes (46.8 and 93.5 L ha-1 ) on commercially grown alfalfa in California. Residue levels and spray coverage were also comparable and consistent between the UAV and airplane applications across three sampling techniques, specifically residue levels on alfalfa, insecticide recovery from filter paper, and spray coverage on water sensitive cards. Differences in droplet size and deposit characteristics were more variable for the UAV than airplanes based on analysis of deposition images. CONCLUSION: The results of this study provide confidence supporting the use of small-scale multi-rotor UAVs for pesticide application on agricultural crops. According to the parameters tested, UAV application quality and crop protection performance were comparable to that of the conventional fixed wing airplane application. However, the droplet spectrum and the short-term fate of droplets from unmanned aerial spray system require further optimization for effective and efficient crop protection with minimal risk to the environment.


Assuntos
Medicago sativa , Praguicidas , Animais , Proteção de Cultivos , Insetos , Controle de Pragas
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