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Thifluzamide, a succinate dehydrogenase (SDH) inhibitor, possesses high activity against Rhizoctonia. In this study, 144 Rhizoctonia solani AG-4 (4HGI, 4HGII, and 4HGIII) isolates, the predominate pathogen associated with sugar beet seedling damping-off, were demonstrated to be sensitive to thifluzamide with a calculated mean median effective concentration of 0.0682 ± 0.0025 μg/ml. Thifluzamide-resistant isolates were generated using fungicide-amended media, resulting in four AG-4HGI isolates and eight AG-4HGII isolates with stable resistance and almost no loss in fitness. Evaluation of cross-resistance of the 12 thifluzamide-resistant isolates and their corresponding parental-sensitive isolates revealed a moderately positive correlation between thifluzamide resistance and the level of resistance to eight other fungicides from three groups, the exception being fludioxonil. An active efflux of fungicide through ATP-binding cassette and major facilitator superfamily transporters was found to be correlated to the resistance of R. solani AG-4HGII isolates to thifluzamide based on RNA-sequencing and quantitative reverse transcription-PCR analyses. Sequence analysis of sdhA, sdhB, sdhC, and sdhD revealed replacement of isoleucine by phenylalanine at position 61 in SDHC in 9 of the 12 generated thifluzamide-resistant isolates. No other mutations were found in any of the other genes. Collectively, the data indicate that the active efflux of fungicide and a point mutation in sdhC may contribute to the resistance of R. solani AG-4HGI and AG-4HGII isolates to thifluzamide in vitro. This is the first characterization of the potential molecular mechanism associated with the resistance of R. solani AG-4 isolates to thifluzamide and provides practical guidance for the use of this fungicide.

The soil inhabits many microbes, including plant parasitic nematodes. Plant parasitic nematodes are reported to cause substantial damage to crops which results in yield and economic losses. Chemical control is the most widely used method to control plant parasitic nematodes. However, the consequences of synthetic chemicals are detrimental to human health, animals, and the environment and face so many strict regulatory measures. Synthetic chemicals are also not reliable with their inability to provide long-term protection. Many studies have shown that the use of beneficial fungi and bacteria has the potential to prevent and suppress plant parasitic nematodes while keeping the environment safe. Several experiments have demonstrated that bioproducts of microbial origin are cheap, safe, and provide long-lasting biocontrol effects against pathogens both in vitro and field conditions. Therefore, this review aims to discuss mechanisms that beneficial microbes and their products use to successfully suppress plant parasitic nematodes. The review also explains the importance of using commercial bionematicides in the sustainable management of plant parasitic nematodes. The existing challenges that are limiting the full application of beneficial microbes, and what needs to be done to fully utilize biocontrol agents in the management of plant parasitic nematodes have also been discussed. To the best of our knowledge, this review has come at the right time to give researchers and plant growers more options when several synthetic chemical nematicides are being banned by regulatory authorities due to their hazardous effects.

Anthracnose, mainly caused by Colletotrichum gloeosporioides species complex including Colletotrichum fructicola and Colletotrichum siamense, is a devastating disease of peach. Chemical control has been widely used for years, but management failures have increased with the commonly used fungicides. Therefore, screening of sensitivity of Colletotrichum spp. to fungicides with different modes of action is needed to make proper management strategies for peach anthracnose. In this study, the sensitivity of 80 isolates of C. fructicola and C. siamense was screened for pyraclostrobin, procymidone, prochloraz, and fludioxonil based on mycelial growth inhibition at discriminatory doses. Results showed that C. fructicola and C. siamense isolates were highly resistant to procymidone and fludioxonil with 100% resistance frequencies to both fungicides, but sensitive to prochloraz, i.e., no resistant isolates were found. For pyraclostrobin, 74% of C. fructicola isolates showed high resistance, 26% showed low resistance, and all of the C. siamense isolates showed low resistance. No positive cross-resistance was observed between pyraclostrobin and azoxystrobin even when they are members of the same quinone outside inhibitor (QoI) fungicide group or between pyraclostrobin and non-QoIs. Resistant isolates to QoI fungicides were evaluated for the fitness penalty. Results showed that no significant differences except for the mycelial growth rates that were detected between high- and low-resistance isolates of C. fructicola. Molecular characterization of the Cyt b gene revealed that the G143A point mutation was the determinant of the high resistance in C. fructicola. This study demonstrated the resistance status of C. fructicola and C. siamense to different fungicides and briefly discussed implications of that resistance. Demethylation inhibitor fungicides were found to be the best option among the different chemicals studied here, to control peach anthracnose in China.

Salt cedar (Tamarix spp. L), is found across Texas and the western United States, primarily near riparian areas. Introduced in the 1800s as an ornamental plant, salt cedar escaped domestic gardens, invading native rangelands. Mechanical and chemical control options for salt cedar are available, but effective control can be difficult and cost prohibitive. Sheep and goats will readily consume salt cedar after exposure at weaning, and goats readily consume the plant when released on rangelands. Unfortunately, sheep and goats are not a viable option in many areas due to predation or lack of appropriate fencing. The objectives of this study were to determine if cattle would consume salt cedar at a similar level (body weight basis) as sheep and goats and to determine if preconditioning improved acceptance of salt cedar by cattle. Angus-Hereford cross heifers (n = 15), Rambouillet lambs (n = 15), and Boer-Spanish cross kids (n = 15) were placed in individual pens for 21 d and fed salt cedar leaves and tender stems daily. For the first 21 d, eight head from each species were fed a basal diet and salt cedar while 7 head only received the basal diet. The amount of salt cedar in the diet was increased from 5% of the diet to 10% of the diet after 7 d of feeding and fed until d 21. From d 22 to 28 both naive and familiar animals were fed salt cedar daily. All animals readily increased intake of salt cedar. By d 7, cattle, sheep, and goats consumed the plant, but intake varied daily for cattle and sheep. After the first 7 d, goats consistently ate more (P

Understanding the effects of temperature on Fusarium graminearum infection can provide theoretical guidance for chemical control of Fusarium head blight (FHB). Here, we evaluated the effects of various temperatures on biological fitness development of wild-type sensitive strain 2021 and carbendazim-resistance mutants conferring β2-tubulin substitutions F167Y, E198K, and E198L. The results showed that mycelial growth and conidiation of four strains increased with the increase in temperature between 10 and 25°C. Conidia of F167Y displayed strong adaptability to low temperature. The virulence of the four strains was largely similar at the same temperature, showing an upward trend between 10 and 25°C. At 10°C, the hyphal growth of all strains was significantly inhibited, metabolism was slowed down, and the accumulation of secondary metabolites decreased. Subsequently, the production of deoxynivalenol (DON) and its intermediates pyruvate and aurofusarin decreased at low temperature, and the expression of DON biosynthesis-related genes Tri5, FgPK, and AUR decreased accordingly. At the same temperature, the aurofusarin production of the strains F167Y and E198K was higher than that of strains 2021 and E198L. The contents of DON and pyruvic acid in carbendazim-resistance mutants were higher than those in the wild-type strain 2021. The sensitivity of four strains to different fungicides changed at various temperatures. The sensitivity to most fungicides increased with decreasing temperature. The carbendazim-resistance mutants showed positive cross-resistance with other benzimidazoles. However, there was no cross-resistance to pyraclostrobin and azoles. These results would direct us to use fungicides preventing the infection of F. graminearum with changeable atmospheric temperature at the wheat flower stage.

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato production. Various strategies have been developed and implemented to manage this pest. Here, we present a timely review on the up-to-date development and practical implementation of integrated pest management (IPM) programs for tomato crops across different world regions infested by T. absoluta. While insecticide resistance is a growing concern, biological control via releasing or conserving arthropod natural enemies and sex pheromone-based biotechnical control are the most successful management practices. Agronomic control-related research is an emerging area where the soil fertilization and/or irrigation, as well as breeding of resistant cultivars, has the potential to enhance IPM effectiveness. Grower survey responses in the native areas (i.e., South America), early-invaded areas (i.e., first report between 2006 and 2012) and newly invaded areas (i.e., first report after 2012) showed that the control programs evolved along with the areas and time since invasion. Growers in the early-invaded areas shifted more rapidly from chemical control to biological control compared to those from the native area. In all concerned regions, the pest control failure risk following chemical insecticide applications and the high cost associated with either biological or biotechnical control methods have been the greatest concerns for growers. The information gathered from the native and/or early-invaded areas may help achieve a more effective management in newly invaded areas. Lastly, researchers are expected to break the bottlenecks of some key issues that would enable lowering application cost of novel biorational alternative management options.

Made available in DSpace on 2022-04-28T19:44:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The aim of this study was to assess the efficacy of imazamox for control of S. molesta and to assess the effects of plant decomposition on environmental indicators after application of this herbicide in microcosm conditions. The following rates were used: 600, 700, 800 and 900 g ai ha−1 and spray volume 50 L ha−1. Control efficacy was determined as the percentage (from 0 to 100%) of visible injury symptoms in the plants, biochemical and chemical oxygen demand (BOD5 and COD), water quality variables, chlorophyll a and pheophytin a at 0, 7, 15, 30, 45 and 60 days after application (DAA) and fresh and dry biomass at 60 DAA. Imazamox was effective in controlling 94% of S. molesta with 900 g ai ha−1; it reduced 95% of fresh weight and 92% of dry weight of plant at 60 DAA, and reduced chlorophyll a of the plants for all rates. For BOD5, there was an increase for all rates at 15, 30 and 45 DAA with restoration of the parameters at 60 DAA, and for COD, there was an increase at 60 DAA with 700 and 900 g ai ha−1. For temperature, pH, dissolved oxygen and electrical conductivity, there was no significant effect after spraying. Imazamox was effective in controlling S. molesta with 900 g ai ha−1 without causing significant effects on the physical-chemical parameters of water quality. College of Agricultural and Veterinary Science São Paulo State University University Center of the Barretos Educational Foundation Ecosafe - Agriculture and Environment Department of Plant Health College of Agricultural and Veterinary Science São Paulo State University College of Agricultural and Veterinary Science São Paulo State University Department of Plant Health College of Agricultural and Veterinary Science São Paulo State University

Mouthwashes are an effective complementary method in the biofilm prevention and chemical control, when the practice of mechanical removal is insufficient. Among the active compounds most used in antiseptics are chlorhexidine, cetylpyridinium chloride, triclosan and essential oils. In order to reduce undesirable effects, such as teeth and restorations staining and the supragingival calculus formation, observed mainly after use for long periods, natural products of plant origin have been extensively studied and incorporated into oral hygiene formulations. Commonly used as a functional food or spice in world gastronomy, Coriandrum sativum (C. sativum), popularly known as coriander, is a natural therapeutic resource with several properties, including antifungal and antioxidant ones. Thus, the objective of this study was to carry out a literature review of articles published in the last 10 years that relate natural products, dentistry and C. sativum, in order to understand the role of naturally occurring agents with potential therapeutic applications in the dental fields, as well as to evaluate the application of C. sativum in the treatment of oral diseases. Therefore, a bibliographic search was carried out in the ScienceDirect and PubMed databases, obtaining 20 articles. It was possible to confirm the antifungal properties and the mode of action of the essential oil from C. sativum in Candida species, as well as its relatively low cytotoxicity in human cells. These findings should encourage further studies for the development of mouthwashes based on C. sativum as an alternative to mouthwashes available on the market.Keywords: Dentistry. Biological Products. Coriandrum. Oral Health.ResumoOs enxaguatórios bucais constituem um método complementar eficaz na prevenção e controle químico do biofilme, quando a prática de remoção mecânica se mostra insuficiente. Dentre os compostos ativos mais utilizados em antissépticos estão a Clorexidina, o cloreto de cetilpiridíneo, o triclosan e os óleos essenciais. Buscando a diminuição de efeitos indesejáveis, como manchamento de dentes e restaurações e a formação de cálculo supragengival, observados principalmente após a utilização por longos períodos, produtos naturais de origem vegetal têm sido amplamente estudados e incorporados nas formulações para higiene bucal. Comumente utilizado como alimento funcional ou especiaria na gastronomia mundial, o Coriandrum sativum (C. sativum), popularmente conhecido por coentro, apresenta-se como um recurso terapêutico natural com diversas propriedades, incluindo antifúngica e antioxidante. Assim, o objetivo deste estudo foi realizar uma revisão de literatura de artigos publicados nos últimos 10 anos que relacionam produtos naturais, a odontologia e o C. sativum, a fim de compreender o papel de agentes de ocorrência natural em aplicações terapêuticas potenciais na área odontológica, bem como avaliar a aplicação do C. sativum no tratamento de doenças bucais. Para isso foi realizada uma busca bibliográfica nas bases de dados ScienceDirect e PubMed, obtendo-se 20 artigos. Foi possível confirmar as propriedades antifúngicas e o modo de ação do óleo essencial de C. sativum em espécies de Candida, bem como sua citotoxicidade relativamente baixa em células humanas. Esses achados devem incentivar novos estudos para o desenvolvimento de enxaguatórios bucais baseados em C. sativum como alternativa aos enxaguatórios bucais disponíveis no mercado.Palavras-chave: Odontologia. Produtos Biológicos. Coriandrum. Saúde Bucal.

Apple powdery mildew, caused by Podosphaera leucotricha, continues to be a challenge in commercial apple orchards in the U.S. Pacific Northwest and worldwide. In this study, P. leucotricha isolates were collected in 2018 and 2019 from two organic (baseline) and eight conventional (exposed) apple orchards in Washington, New York, and Virginia, and assessed for their sensitivity to trifloxystrobin (TRI, n = 232), triflumizole (TFZ, n = 217), and boscalid (BOS, n = 240) using a detached leaf assay. Effective concentrations inhibiting 50% growth (EC50) were not significantly different between baseline and exposed isolates, and ranged from 0.001 to 0.105, 0.09 to 6.31, and 0.05 to 2.18 µg/ml, for TRI, TFZ, and BOS, respectively. Reduction in sensitivity by factors of 105, 63, and 22 to TRI, TFZ, and BOS, respectively, were observed in some isolates, but all isolates were controlled by the commercial label rates of the three fungicides on detached leaves. Sequencing of the cytochrome b (cytb), cytochrome P450 sterol 14α-demethylase (CYP51), and the iron-sulfur protein subunit (SdhB) genes in isolates with high EC50 revealed no mutation previously reported to confer resistance to these fungicides in other fungi, and presence of a group I intron after codon 143 in the cytb gene. Significant (P < 0.001) moderate positive correlations (r = 0.38) observed between sensitivity to TRI and TFZ warrant continuous rotations of fungicides with different modes of action in conventional orchards. The established baseline sensitivities and the molecular markers will help in selecting discriminatory doses and bypassing the challenging in vivo testing for future sensitivity monitoring in P. leucotricha.

Leaf spot, or black spot (BS), caused by the fungus Pseudocercospora purpurea (Cooke) Deighton, is one of the principal sanitary limitations in avocado production, particularly in the Antillean cultivars (Lorena, Choquette, Santana, and Semil 44) in the northern region of the Department of Tolima, Colombia. From 2014 to 2017, different experiments were carried out in the field to determine when higher fruit susceptibility occurs, the effect of pruning on inoculum reduction, and the chemical molecules with a high degree of control, adjusting their chronology and frequency of application. The results will facilitate the technical, economic, and environmental implementation and validation of a chemical strategy for management of this disease. The management strategy carried out with Agrosavia reported a 10% lower BS incidence in the fruits, as compared to the one carried out by producers, and a 23.75% return as a result of the increased fruit quality. This strategy used DMI fungicides (demethylation inhibitors), without resistance reports, and fungicides with a mixture of two active ingredients (DMI and QoI) and interspersed applications, sometimes in conjunction with CuOCl during periods of higher BS susceptibility in order to reduce the resistance induction risk in P. purpurea. RESUMEN La peca o mancha negra del aguacate causada por el hongo Pseudocercospora purpurea (Cooke) Deighton, es una de las principales limitantes sanitarias para la producción de aguacate de los cultivares antillanos (Lorena, Choquette, Santana y Semil 44) en la región productora del norte del departamento del Tolima, Colombia. Durante 2014-2017, se realizaron diferentes experimentos en campo con el propósito de determinar la época de mayor susceptibilidad del fruto, el efecto de la poda en la disminución del inóculo, y la selección de moléculas químicas con mayor grado de control, ajuste de su cronología y frecuencia de aplicación. Estos resultados permitieron la implementación y validación técnica, económica y ambiental de una estrategia química de manejo de la enfermedad. La estrategia de manejo realizada por Agrosavia (MA) reportó una incidencia de peca en fruto menor en un 10% en comparación con la observada en el manejo realizado por los productores (MP), con una rentabilidad de 23,75% debida al incremento de frutos de primera calidad. En esta última se emplearon fungicidas DMI (inhibidores de la demetilación) aún sin reportes de resistencia, fungicidas con mezcla de dos ingredientes activos (DMI y QoI) en aplicación intercalada, y algunas veces en conjunto con CuOCl durante la época de mayor susceptibilidad de los frutos a la peca, encaminada a disminuir el riesgo de inducción de resistencia en P. purpurea.

Pyricularia oryzae is the etiological agent of rice blast, the most destructive disease in rice crops and chemical control based on fungicide is the main method used in its management. The aim of this study was characterize pathogenicity and identify P. oryzae isolates adapted to tricyclazole. P. oryzae monosporic isolates were collected in the state of Tocantins and inoculated in international differentiating series of rice cultivars for determination of pathotypes. After, the same isolates were inoculated in the rice cultivar IRGA 424 to evaluate resistance to fungicide Bim® 750 BR (Tricyclazole - 250 g/ha) that was applied 24 and 48 hours after pathogen inoculation (hai). Leaf blast severity and infection efficiency were evaluated 9 days after inoculation (dai), latency period (2 dai) and sporulation intensity (7 dai). Nine different pathotypes were identified, predominantly as IA group. The latent period of isolates occurred between from 48 to 120 h. The application of tricyclazole, 24 hai reduced disease severity with the exception of the isolate Py 7.1. The great variability of the pathogen allowed for adaptation to this molecule and can increase its aggressiveness and should be considered to guide the integrated management of the disease.

The outbreak and spread of huanglongbing (HLB) disease have brought about tremendous negative effects and economical losses on citrus production all over the world. The scientists have carried out various preventive and therapeutic methods including genetic improvement, seedling detoxification, chemical control, physical control and biological control to contain huanglongbing harmfulness. Compared to other methods, trunk injection technology is a promising, precise and environmentally friendly treatment method which has achieved valuable effectiveness by utilizing various injection apparatus. In this paper, the critical factors influencing the effectiveness of trunk injection implementations are reviewed in multiple aspects including biology, chemistry, ecology and technique. The researchers concluded that the research results of delivering liquid pesticides or antibiotics to cure various tree diseases and manage invasive pests by trunk injection demonstrated remarkable manifestation. Furthermore, the studies and technological tendencies including the trunk injection interactive mechanism and fundamental theories, the specialized injectable chemical substances adapting to different tree species or diseases, the reduction and closure of trunk injuries, the development of high-efficiency trunk injection automatic equipment, etc., are presented and discussed at the end of this paper. The researchers need to carry out fundamental theoretical researches and interaction mechanisms between injection system and target. The development of automated and accurate high-efficiency injection devices and integrated pest management platform with the functionalities of detection, prevention, treatment, environmental monitoring and key technologies of AI, flexible manipulator operations, agricultural sensors, are the promising tendencies of precision agriculture.

During propagation of avocado by grafting in 2019 and 2020, the maximum % grafting failure (GF) of avocado seedlings was recorded on cv. Hass and cv. Fuerte, followed by cv. Benkerton and cv. Reed. While cv. Etinger was the less susceptible one. Lasiodiplodia theobromae was the most frequently isolated from graft failure seedlings in all avocado cultivars, followed by Fusarium moniliforme. While Alternaria alternata recorded the lowest frequency. The highest percentage of grafting failure and death of scions was obtained by the fungus L. theobromae,followed by F. moniliforme and the lowest percentage of grafting failure was observed forA. alternata in all avocado cultivars. The efficacy of biological and chemical control was tested in vitro and in vivo as well as under nursery conditions for controlling GF on avocado seedlings. Amistar Top and Bellis gave the highest reduction in colony growth of the three pathogens, followed by Kocide (2000) and Star copper. While Serenade ASO and Bio Zeid were the lowest ones. Dipping scions in each of the tested suspensions before dipping in spore suspension of each fungus suppressed the spores of the pathogen during grafting and increased the percentage of success of grafted seedlings in the two tested cultivars Hass and Fuerte compared with the control. In this respect, Amistar Top and Bellis were the most effective treatments for controlling the pathogens in the two tested cultivars, followed by Kocide (2000) and Star copper. The lowest efficacy was recorded when scions were dipped on Serenade ASO and Bio Zeid. Also, dipping scions in the suspension of each tested commercial product during grafting increased the percentage of grafting success for all tested cultivars compared with the control. Considering the means of efficacy of the tested treatments on the tested cultivars in the two seasons, Amistar Top, Bellis and Kocide (2000) were the most effective which recorded (91.00 and 94.00%), (85.00 and 87.00%) and (84.00 and 87.00%), respectively (%) success of avocado grafted seedlings on all cultivars in the two years, followed by Serenade ASO (83.00% and 87.00%). While the least (%) success of avocado grafted seedlings on all cultivars in the two seasons was observed on Star copper and Bio Zeid (81.00 and 86.00%) and (81.00 and 84.00%), respectively. Also, the highest effect of all treatments was on cv. Etinger, cv. Reed and cv. Benkerton, while the lowest effect was on cv. Fuerte and cv. Hass in the two seasons. The highest values of production of peroxidase and polyphenoloxidase activities in the two tested avocado cultivars Hass and Fuerte were observed after dipping the scions in Amistar Top and Bellis, followed by Kocide (2000) and Serenade ASO. While the lowest values of peroxidase and polyphenoloxidase activities were recorded after dipping the scions in Star copper and Bio Zeid.

Se presentan antecedentes técnicos y económicos para la toma de decisiones, especialmente de los pequeños y medianos propietarios, respecto a métodos de manejo de la regeneración natural de Pinus radiata, para recuperan las plantaciones afectadas por los mega incendios forestales del año 2017en la región del Biobío. Se analizan dos predios de la comuna de Florida, donde se manejó la regeneración de pino con desbrozadora, herbicidas y herramientas manuales, observándose que el control manual presentó los menores valores de crecimiento en diámetro de cuello, mientras que la utilización del control químico generó los mayores valores en diámetro de cuello y altura.

Ascochyta blight epidemics have been observed in many countries since the early 1900s but studies on an interaction between the amount of inoculum, environmental factors and the spatiotemporal development of Ascochyta blight are rare due to the historic emphasis on developing resistant cultivars and chemical control of the disease. I used generalised linear mixed models to investigate key environmental factors affecting the spatiotemporal development of Ascochyta blight from primary infection foci. Briefly, four replicate plots (20 m × 20 m) of a susceptible chickpea cultivar were planted at two different locations (Billa Billa and Tosari) in Queensland, Australia. Four naturally infested stubble pieces were placed at the centre of each newly emerged chickpea plot 14 days after sowing. The number of infected plants was counted in 1 m2 observation quadrats at the distances of 3, 6 and 9 m in a concentric arrangement. The number of infected plants increased with each assessment date, approaching 100% plant infections at the time of final assessment. The rate of disease progress was significantly faster at Tosari. The rate of disease progress significantly decreased as the distance from the primary infection foci increased. There was a significant positive effect of an optimum temperature, increasing rainfall and omni-directional wind. The influence of wind speed was not significant. The finding that single infection foci were enough to spread disease across whole plots indicate that limited inoculum is not a barrier in the development of an epiphytotic under conducive conditions.

Made available in DSpace on 2021-09-06T15:00:55Z (GMT). No. of bitstreams: 1 ppa.13418.pdf: 2536352 bytes, checksum: 0f167241bd0fcdb0e4e8396760c9ca5f (MD5) Previous issue date: 2021

Uno de los principales problemas fitosanitarios en la producción de tomate o jitomate (Solanum lycopersicon Mill.) donde se utiliza el suelo como medio de cultivo es Fusarium spp., el control químico es el método frecuentemente utilizado para su manejo; con impactos económicos y ambientales importantes. Los objetivos del presente estudio fueron: evaluar el repollo como cultivo de rotación y la incorporación de los residuos al suelo sobre la incidencia de la marchitez permanente en plantas de tomate e incidencia de Fusarium spp., en el suelo y evaluar la supresión de Fusarium spp., mediante la aplicación de subproductos de hojas y tallos de repollo. El trabajo se realizó en dos etapas: en la primera se documentó la evolución de Fusarium spp., en un cultivo comercial de tomate, establecido bajo condiciones de malla antiáfidos y repollo como cultivo de rotación, durante el periodo de 2012 a 2019. En la segunda etapa, se evaluó un extracto acuoso y un polvo deshidratado, obtenidos de hojas y tallos residuales de repollo. Los resultados muestran que el repollo utilizado como cultivo de rotación y la incorporación al suelo de las hojas y tallos residuales, redujeron la incidencia de marchitez permanente en el cultivo de tomate y suprimieron eficazmente Fusarium spp. Asimismo, el polvo deshidratado obtenido de estos residuos mostró un efecto similar sobre el control de Fusarium spp., al obtenido en los tratamientos con metilditiocarbamato de sodio.

Fungicide hormesis has implications for the application of fungicides to control plant diseases. We investigated the hormetic effects of the dicarboximide fungicide dimethachlone on mycelial growth and virulence of the necrotrophic plant pathogen Sclerotinia sclerotiorum. Dimethachlone at sublethal doses in potato dextrose agar (PDA) increased the mycelial growth of S. sclerotiorum. After the growth-stimulated mycelia were subcultured on fresh PDA and inoculated on rapeseed leaves, increased mycelial growth and virulence were observed, indicating that hormetic traits were passed down to the next generation. Dimethachlone applied to leaves at 0.002 to 500 μg/ml stimulated virulence, with a maximum stimulation amplitude (MSA) of 31.4% for the isolate HLJ4, which occurred at 2 μg/ml. Dimethachlone-resistant isolates and transformants had a mean virulence MSA of 30.4%, which was significantly higher (P = 0.008) than the MSA for sensitive isolates (16.2%). Negative correlations were detected between MSA and virulence in the absence of any fungicide (r = –0.872, P < 0.001) and between MSA and mycelial growth on PDA (r = –0.794, P = 0.002). Studies on hormetic mechanisms indicated that dimethachlone had no significant effects on expression levels of three virulence-associated genes, that is, a cutinase-encoding gene SsCut, a polygalacturonase gene SsPG1, or an oxaloacetate acetylhydrolase gene SsOah1. The results will contribute to understanding hormesis and have implications for the judicious application of fungicides to control plant diseases.

El manejo integrado de plagas (MIP) requiere la compatibilidad del control químico y control biológico. El objetivo de esta investigación fue evaluar la toxicidad de los insecticidas spinetoram y matrine sobre los estados de desarrollo de dos enemigos naturales: Chrysoperla externa y Ceraeochrysa cincta. Se realizaron ensayos toxicológicos con spinetoram y matrine. Los productos fitosanitarios no afectaron la eclosión de los huevos y la emergencia de las pupas de ambas especies mediante ensayos de inmersión. Se obtuvieron altos porcentajes de mortalidad en adultos por contacto residual al usar spinetoram. Los adultos mostraron mayor susceptibilidad que el estado larval mediante ensayos de ingestión. Según la catalogación toxicológica para ensayos de laboratorio por contacto residual, la máxima concentración evaluada de spinetoram fue ligeramente nociva para larvas del primer y segundo estadio de C. externa, y ambas concentraciones fueron ligeramente nocivas para adultos de C. externa. Asimismo, ambas dosis fueron moderada y ligeramente nocivas en adultos de C. cincta. Finalmente, ambos productos fueron inofensivos en todos los estadios larvales de C. externa y C. cincta, mientras que el spinetoram fue ligeramente nocivo en adultos de ambas especies y solo la máxima concentración de matrine fue ligeramente nociva en adultos de C. cincta.

Weed management in coffee plants is carried out largely through the adoption of chemical control, with the use of herbicides. In this context, one of the species that most affects the development of coffee plants, and due to its difficulty in control, is sourgrass. Above all, most sourgrass biotypes are not efficiently controlled with the herbicide glyphosate, which is the most used in coffee growing. Thus, the search for strategies that can minimize the damage caused by this weed, appears with increasing demand, due to the great damage to coffee plants. Therefore, the objective of this study was to evaluate the chemical control of adult sourgrass in coffee plants, through several associations. Treatment control efficiency was visually evaluated, where a scale ranging from 0 to 100 was used, with 0 corresponding to the absence of symptoms and 100 corresponding to the total control of weed plants by the action of herbicides, respectively. This evaluation method was used at 7, 14, 21, 28, 35 and 42 days after application. The data obtained were subjected to analysis of variance using the SISVAR statistical software. The association of the herbicides Fluazifop-p-butyl and Clethodim, implies greater efficiency in controlling sourgrass over time. The association of the herbicide ammonium glufosinate with systemic herbicides implies a reduction in the control capacity of sourgrass plants over time.

El objetivo fue evaluar el grado de infestación natural por Rhipicephalus microplus, así como determinar su correlación con factores climatológicos y su efecto sobre la ganancia de peso en bovinos doble propósito. Se utilizaron 31 bovinos cruzados, Bos taurus x Bos indicus, de ambos sexos, con una edad promedio de 307 días. El conteo de garrapatas semi-repletas (4.5 a 8.0 mm de diámetro) y el pesaje de los animales se realizaron cada 28 días. El conteo de garrapatas se realizó desde la cabeza hasta la base de la cola, abarcando miembros anteriores y posteriores, así como la región ventral de los animales. Las variables de respuesta estudiadas fueron número de garrapatas semi-repletas y ganancia de peso promedio del animal. En julio el número promedio de garrapatas por animal fue mayor (P0.05) el número de garrapatas. La ganancia de peso disminuyó 34 g (P

Walnut blight (WB), caused by the bacterium Xanthomonas arboricola pv. juglandis,continues to be a serious disease of walnut in northern China, where weather conditions favor disease development. From 2013 to 2017, WB incidences in walnut cv. ‘Liaoning 1’ were investigated in three areas (Dalian,Suizhong and Jianchang areas) in the Liaoning province, northeastern China. WB incidence was high in Dalian (23.72%) and Suizhong (24.31%) but was low in Jianchang (12.98%). Relative humidity is a key meteorological factor that affected the differences between areas. Ten walnut cultivars were surveyed in 2013, 2015, and 2017 for their susceptibility to blight. Lateral-bearing walnut cultivars showed a higher incidence and were found more susceptible to WB compared with terminal-bearing cultivars. In order to test the most effective chemical spray methods, bactericide screening trials were conducted comprising 12 different types of bactericides and mixtures in 2015. The combination of kasugamycin+mancozeb was most effective in controlling WB incidence resulting in lowest fruit disease incidence (2.63%). Subsequently, minimal spray trials were studied to determine the most effective chemical control as well as timing and frequency of application in 2017. The study confirmed these results of studies done in California: the best timing for the first spray application was at 30%–40% pistillate flower emergence and subsequently spray times were at 6 days and 16 days interval. Results of this study provide essential information to better understand the complexity of this walnut disease toward developing effective control management strategies globally.

Guava (Psidium guajava L.) wilt is extremely severe and soil borne disease, i.e. difficult to control once the symptoms appear on the plant foliage. It is mainly caused by the fungi like Fusarium o...

Drosophila suzukii (Matsumura) is an invasive pest of soft-skin fruits. Due to its recent introduction, there are currently no studies about its chemical control in Argentina. The aim of this resea...

Cattle are challenged by numerous tick species in the western highlands of Cameroon. Consequently, several tick-borne diseases (TBDs) are known to be endemic in this region. To face this situation, farmers mainly resort to the use of chemical acaricides. But to date, no study has focused its attention on the evaluation of tick control methods in this area. Therefore, the present study was designed to assess the knowledge and practices of breeders against ticks and TBDs in Menoua Division. A descriptive cross-sectional survey was conducted in 4 Sub-divisions of Menoua Division. Breeders who consented to the study were interviewed using semi structured questionnaires. Interviews were conducted in French, English or local language (Fulfulde). The questionnaire was made of 25 questions sectioned into; (i) farmer’s knowledge on ticks and TBDs, (ii) treatment practices of infested animals and, (iii) the estimated amount spent for vector control of ticks. All the breeders interviewed had a good knowledge on ticks and the main direct effects they inflict on animals. However, only 7% of respondents associated ticks to the main TBDs. Manual removal and chemical control using synthetic acaricides (usually pyrethrinoids) were the main methods of tick control. Despite the multiplication of treatments (on average 1/week), their effectiveness was not perceived by almost all breeders (82.0%; n = 82) who complained of treatment failures, regardless of the sites and molecules used. In addition, each farm spent on average 8, 521 ± 2, 968 CFAF (US$16.08 ± 5.6)/month for vector control. That is a cumulative amount of CFAF 588, 000 (US$1, 109.45)/month and CFAF 7, 056, 000 FCFA (US $ 13, 313.49)/year for all the farms visited. The lack of pasture (OR = 43.5; p

Recently, a wide range of symptoms including light yellow lesions gradually turning into brown stripes were noticed on date palm leaves in Iraq. In this context, the aim of this study were to isolate the phytopathogens associated with these symptoms, evaluate their pathogenicity and assess the efficacy of two fungicides (Score and Pentanol) under in vitro and in vivo conditions. Two fungal species (Alternaria sp. and Fusarium sp.) were isolated from the symptomatic leaves of date palm. The results of pathogenicity tested proved the ability of Alternaria sp. inoculated separately or in combination with Fusarium sp. to infect the leaves of date palm trees with disease severity index (DSI) values of 67.33% and 65.99%, respectively. The effect of Score (88.76%) and Pentanol (82.91%) against Alternaria sp. was examined by poisoned food technique, which leads a significant increase in mycelial growth inhibition (for 300% of commercial recommended dose of fungicide). Test results indicate that prophylactic spraying of date palm leaves with Score or Pentanol effectively controlled Alternaria sp. with DSI values of 22.65% and 17.87%, respectively. To control Alternaria sp. in field within integrated pest management strategies, chemical control using Score or Pentanol should be taken in consideration.

Plant parasitic nematodes (Root-knot nematodes, Meloidogyne spp.) are rounded worms, microscopic, and cause many agricultural economic losses. Their attacks have a direct impact on the productivity of cultivated crops by reducing their fruit quantity. Chemical control is widespread all over the world, but biological control is the most effective way to reduce the number of pests that infect crops, particularly by the use of microorganisms like fungi and bacteria. Biological control is rapidly evolving, and more products are being sold worldwide over time. They can be produced by fungi, bacteria, or actinomycetes that can destruct plant parasite nematodes and feed on them. Nematophagous microorganisms as the natural enemies of nematodes have a promising way of controlling nematodes. Some of them create net-like substances and traps to take the worms from outside and finally kill them. Other parasites serve as internal parasites in order to produce toxins and to produce virulence to kill nematodes. Comprehension of the molecular basis for microbial nematode interactions gives important insights into how successful biological nematode control agents can be created. We discuss recent advances in our understanding of nematodes and nematophagous microorganisms, with an emphasis on molecular mechanisms that infect nematodes with nematophagous microorganisms and on nematode safety from pathogenic attacks. Finally, we addressed numerous key areas for future research and development, including possible approaches to the application of our recent expertise in the development of successful biocontrol strategies.

One of the most important factors in the formation of cocoa crops is the use of quality seedlings. However, during the formation of seedlings in the nursery, competition for weeds can limit their development. Thus, the objective was to evaluate the efficiency of application of the herbicides Clethodim and Flumioxazin in the control of weeds and their effects on the development of cocoa seedlings under nursery conditions. A completely randomized design was adopted, in a 2x6 factorial scheme with four replications, the first factor being the herbicides clethodim and flumioxazin and the second factor representing the doses of these herbicides, in which, 0, 1, 2, 4, 8, 16 L ha-1 corresponding to 0, 24, 48, 96, 192, 384 g ia ha-1 of the active ingredient Clethodim and 0, 30, 60, 120, 240, 480 g ia ha-1 of Flumioxazin respectively. At 120 days after emergency application of the plants, the effects caused by herbicides on the development of cocoa seedlings and their effectiveness in weed control were evaluated. The post-emergence use of the herbicide clethodim promoted a better development in the cocoa seedlings in relation to the pre-emergence application of the herbicide Flumioxazin. Both herbicides were efficient in controlling weeds, the maximum control being obtained with the dose of 4.61 L. ha-1 of these herbicides, which corresponds to 110.4 g ai ha-1 of the herbicide clethodim and 138 g ia ha -1 of flumioxazin.

Yellow mosaic disease caused by tomato leaf curl New Delhi virus is very severe and causing 100 per cent yield loss under epiphytotic conditions. Chemical control of this disease is neither economical nor eco-friendly and genetic resistance is an efficient means for its management. Resistance to yellow mosaic disease in advanced inbred line IIHR-Sel-1 and IIHR-137 have been confirmed during screening experiment. A crossing programme was planned using Arka Prasan as susceptible and IIHR-Sel-1 and IIHR-137 as resistant parents. We used the F1, F2, BC1 and BC2 generations derived from the two crosses viz. Arka Prasan × IIHR-Sel-1 and Arka Prasan × IIHR 137 to study the inheritance of resistance to yellow mosaic disease. Results indicated monogenic recessive resistance to yellow mosaic disease in the genetic background of both parents which need to be confirmed through repeated experiments with large population size. These results are imperative for breeding yellow mosaic disease resistant cultivars in Luffa species.

Aims: This study aimed to evaluate the control of Eleusine indica Gaertn. and Digitaria insularis (L.) Fedde through the combination of soil cover with green manure straw and herbicides applied in pre-emergence. Study Design: Each weed species was evaluated in different experiments. The experiments were set up in a greenhouse in a completely randomized design and arranged in a factorial scheme (5×4)+2, with four replications. Place and Duration of Study: Center of Agricultural Sciences, São Paulo, Brazil, from May 2019 to May 2020. Methodology: Seeds of Digitaria insularis and Eulesine indica were sown at a depth of 1 cm from the soil surface. Then, the pots were watered, and the straw of Cajanus cajan, Sorghum bicolor, Crotalaria juncea, Crotalaria spectabilis, and Crotalaria breviflora was deposited on the surface. The pre-emergence herbicides trifluralin (900 g ai ha−1), pendimethalin (1200 g ai ha−1), clomazone (1000 g ai ha−1), and s-metolachlor (1920 g ai ha−1) were applied one day after the weed seeds were sown. The percentage of weed control was evaluated at 10, 20, and 30 days after emergence (DAE). The plant shoot was cut at 30 DAE and the weight of dry biomass was determined. The control without herbicide and with soil cover crop and no herbicide and no soil cover were also evaluated. Results: Sorghum bicolor, Cajanus cajan, and Crotalaria breviflora were the most effective in controlling Eleusine indica when no herbicide was applied. Only Sorghum bicolor showed a satisfactory control of Digitaria insularis without the use of chemical management (above 80%). The association of pre-emergence herbicides with soil cover showed high control of weeds. Conclusion: The results showed that the association between chemical and cultural methods is an effective alternative to control Eulesine indica and Digitaria insularis.

The fall armyworm (Spodoptera frugiperda) is one of the most significant agricultural pests in the world and invaded China in early 2019. We sampled and sequenced RNA-seq data from 15 individuals across different developmental stages. Developmental stages were the larval stage (5th instar larvae and 6th instar larvae), chrysalis stage, and adult stage (female adult and male adult). Individual samples were mainly clustered by developmental stages and we then identified variation between developmental stages of differentially expressed transcripts (DETs). There were 2136 upregulated DETs and 1391 downregulated DETs in the larval stage when comparing larval and chrysalis stages. In the comparison between the chrysalis and adult stages, there were 2033 upregulated DETs and 1391 downregulated DETs in the chrysalis stage. In total, 19,195 abundantly expressed transcripts were obtained and 10% of them were DETs. We then obtained stage-specific DETs to investigate the potential function of the fall armyworm during different developmental stages. We also constructed our annotation background set for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. This indicated that the fall armyworm may undergo active metabolism during its lifespan, even in the chrysalis stage. And it also may experience detoxifying and xenobiotic metabolism throughout its life, especially in the larval stage, which partially explains the difficulty to eradicate using chemical control. Our study is the first insight into the developmental patterns of the fall armyworm and we also provide the fundamental information about enhanced drug resistance at the level of transcriptome. These results are beneficial for a future investigation related to the eradication and/or control stage.

Gray mold, caused by Botrytis cinerea, is a devastating disease that causes significant yield losses in various economically important plants. Fungicide application is one of the main strategies for management of gray mold; however, B. cinerea has developed resistance to various groups of fungicide. In China, benzimidazole-, dicarboximide-, and quinone outside inhibitor-resistant populations of B. cinerea have become dominant. Substitute mutations in fungicide target genes are responsible for resistance in B. cinerea. Based on known resistance mechanisms, molecular methods including loop-mediated isothermal amplification have been developed for rapid detection of resistant isolates of B. cinerea. Because B. cinerea is able to quickly develop resistance to various fungicides, various integrated strategies have been implemented in the last decade, including biological and agricultural practices, to manage fungicide resistance in B. cinerea.

Glyphosate application avoids some problems associated with manually controlling Carpobrotus. However, before it can be extended, we must understand whether residual glyphosate affects the restorat...

BACKGROUND Chemical control is the most used and effective method to control Diaphorina citri, the vector of the phloem-limited bacteria associated with citrus huanglongbing (HLB) disease. The objectives of this study were to determine the effectiveness of flupyradifurone applied via dripping irrigation systems on D. citri. Bioassays were conducted using leaves harvested on various dates post treatment, and insecticide residue in leaf tissue was quantified. RESULTS The drip application of flupyradifurone on citrus trees provided high-level and long-term control against D. citri adult, and the median lethal concentration (LC50 ) for ingestion of flupyradifurone in D. citri was 22.22 mg kg-1 (fresh leaf). Flupyradifurone residue was detected in leaf tissue within 3 days after treatment. The measured level of flupyradifurone peaked on day 40 day after application, and then showed a steady decline in subsequent days for all three applied dosages. The amounts of flupyradifurone in upper, middle, and lower leaves were similar, and trends in the change in concentration of flupyradifurone were consistent. CONCLUSIONS The results demonstrate that flupyradifurone can be a valuable new tool for D. citri management programs, and drip-applied flupyradifurone provides an extended period of control efficacy. This paper could provide a reference to reduce the dependence on foliar-applied insecticides, with associated benefits for non-target exposure to workers and pollinators. © 2021 Society of Chemical Industry.

Within is a comprehensive review of current apple powdery mildew literature, with the taxonomy, morphology, and life cycle of the causal phytopathogen Podosphaera leucotricha described. A discussion of economic impact, environmental aspects contributing to apple powdery mildew epidemiology, options for cultural, chemical, and biopesticide disease control, and fungicide resistance in P. leucotricha is also detailed. The present status of breeding for host resistance and apple cultivar susceptibility is discussed. Finally, emerging research into the biology and management of apple powdery mildew is discussed along with how they may aid future research endeavors.

Fusarium head blight (FHB) is a serious disease of wheat and barley that not only lowers yield but also contaminates the grain with associated mycotoxins such as deoxynivalenol (DON). Chemical control options for FHB and DON include application of triazole fungicides at the anthesis or flowering stage. This presents practical challenges for growers in managing FHB, as the appropriate timing window typically lasts only 3 to 4 days. If this small window is missed, due to weather conditions or technical problems, fungicide application is less effective in controlling FHB and DON. The present work was conducted over 2 years (2019 and 2020) to test the efficacy of a new fungicide (pydiflumetofen + propiconazole) from Syngenta labeled as Miravis Ace in controlling FHB and DON content at 50% head emergence (Feekes 10.3), anthesis (Feekes 10.5.1), and end of flowering (Feekes 10.5.3) stages. Prosaro 421 SC, a standard FHB control triazole fungicide, was used at all three stages for comparison with the test fungicide. Miravis Ace application at 50% head emergence provided significant control over the nontreated check for FHB incidence (2020), FHB severity (2019), and DON content (2019) with control efficacies as high as 51, 69, and 52%, respectively. However, mean control percentages relative to the check were highest with Miravis Ace at anthesis in both 2019 and 2020 for all the FHB parameters. In conclusion, 50% head emergence provides statistically significant control on FHB and DON, but anthesis was the most effective application stage for Miravis Ace.