查看更多>>摘要：In recent years, Gastrodia elata black rot disease has occurred in Qiankou town, Dejiang county, Guizhou Province. Symptoms of the disease appeared in the root of G. elata, and led to tuber rot, necrosis, and a pungent odor. In this study, we aimed to identify the pathogenic fungi causing black rot disease of G. elata by morphological and molecular methods. We isolated and cultured the infected plants and obtained a pure culture of the fungus. According to the morphological characteristics and molecular identification, the pathogen isolated from the tubers of infected G. elata was identified as Fusarium redolens.
查看更多>>摘要：Management options are needed for emerging bacterial diseases such as bacterial leaf streak of corn (maize), caused by Xanthomonas vasicola pv. vasculorum (Xvv). The objective of this study was to determine the potential for seed treatment with strains of Bacillus spp. to provide control of bacterial leaf streak. In two trials of a greenhouse pot experiment, B. pumilus R190 and B. subtilis 6051 were applied to corn seed prior to planting, and the plants were grown to V3 stage when they were inoculated with Xvv. Inoculation in Trial 1 was performed by streaking Xvv cells onto leaf surfaces, while leaves were sprayed with a bacterial cell suspension in Trial 2. In both trials, extensive lesion development occurred on leaves of the no-bacteria control 14 days after pathogen inoculation. Seed treatment with B. pumilus R190 reduced disease severity significantly by 85% and 56% compared to the control in Trial 1 and Trial 2, respectively. Disease severity was reduced by seed treatment with B. subtilis 6051 by 32% and 52% in Trial 1 and Trial 2, respectively, with the disease reduction being statistically significant only in Trial 2. The reduction in the foliar disease resulting from the application of bacteria to seed was an indication that induced systemic resistance was involved as the biological control mechanism. This is the first demonstration that root-colonizing bacteria have potential as biocontrol agents to suppress a foliar bacterial disease in corn.
查看更多>>摘要：Gastrodia elata Blume is a valuable Chinese herbal medicine. G. elata flower tissue with symptoms of gray mold was collected in June 2021 at the G. elata breeding base in Dejiang County and Qixingguan County, Guizhou Province. Botrytis cinerea was isolated from the symptomatic flowers, and the fungus was identified based on morphological characteristics and phylogenetic analyses of the ITS, HSP60, and RPB2 sequences. The pathogenicity test revealed B. cinerea as responsible for causing flower gray mold identified on G. elata. To our knowledge, this is the first report of B. cinerea causing gray mold in G. elata flowers. These findings thus provide a basis for further research on the management of flower gray mold of G. elata.
Perez-Landa, Irving D.Lasa, RodrigoGonzalez-Chi, P. I.Bonilla-Landa, Israel...
7页
查看更多>>摘要：The spotted wing drosophila (SWD) (Drosophila suzukii), originally from Asia, has spread across Europe and North America since 2008, threatening soft fruit crops. Spinosad is widely used due to low toxicity to non-target organisms and proven lethality to SWD. This study aims to examine how to preserve the efficacy of spinosad under environmental conditions in the field. In this context, a dry phagostimulant formulation was prepared to contain spinosad biopolymeric microparticles based on chitosan and sodium lignosulfonate. LC50 (90.17 ppm ai) and LC90 (318 ppm ai) were determined, followed by choice tests that showed the phagostimulant with the microencapsulated spinosad improved results compared to the phagostimulant with unencapsulated spinosad. Laboratory bioassays showed that microencapsulation could extend the effectiveness of this bioinsecticide. The application of the formulation on strawberry leaves in the greenhouse was not as effective after 42 days compared to applications in a Petri dish. Our studies suggest that microencapsulated spinosad could be a useful compound in trapping devices since it offers an environmentally friendly option to control D. suzukii.
查看更多>>摘要：A one-step colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to target the coat protein region of genomic RNA of prune dwarf virus (PDV). WarmStart 2X Master Mix from NEB (New England Biolabs) was used for naked eye observation of positive LAMP reactions, where the changing in color from pink to yellowish indicates a positive result. The detection sensitivity of the new technique was 10-fold higher than that of conventional PCR. The assay's specificity was evaluated against the nucleic acids of potential hosts of PDV, prunus necrotic ringspot virus (PNRSV), and apple mosaic virus (ApMV) from the Ilarvirus genus. The novel RT-LAMP test showed high sensitivity in distinguishing PDV and genome of potential hosts and other Ilarvirus genus members. The RT-LAMP test was proven to be reliable for diagnosis of PDV in infected sweet cherry samples from the field. The specific, sensitive, and quick RT-LAMP test described in this study can be used in laboratories and for PDV surveillance in the field. To best of our knowledge, this is the first report of RT-LAMP detection for PDV.
查看更多>>摘要：Passive dispensers are the most widely used dispensers to control the European grapevine moth, Lobesia botrana (Denis & Schiffermuller) (Lepidoptera: Tortricidae), by mating disruption (MD). Although their efficacy is wellproven, efforts are needed to reduce the use of pheromone without compromising efficacy and to allow lower MD costs. For this purpose, two different widely employed dispenser types in Europe against this pest (Ampoule and Rope dispensers) were evaluated in the field to verify their performance (emission rates and efficacy) in relation to weather conditions. Their release profiles were studied by extracting and quantifying the residual pheromone load over time by gas chromatography. Dispensers' performance in relation to weather conditions was then assessed by correlating the daily emission rates with the mean daily values of several of these variables. Although both dispenser types were efficient in controlling L. botrana populations and reducing fruit damage, their pheromone content and their release rates differed at the end of the crop cycle. The Ampoule dispensers emitted lower amounts of pheromone throughout the study period, whereas the Rope dispensers' emissions were weather-dependent, with higher emission rates at higher mean temperatures and wind speeds. Our results showed that the current commercial MD dispensers could be improved by adjusting their release rates to better reflect actual pheromone requirements.
查看更多>>摘要：Avocado (Persea americana Mill.) is an economically important fruit in tropical and subtropical regions of the world. Anthracnose is the most common and serious postharvest disease of avocado fruits. The disease is caused by different species of Colletotrichum in different countries. In July to October 2021, the avocado fruits harvested from Danzhou city of China showed typical anthracnose symptoms during storage. The disease incidence reached 25.8%. The similar fungal colonies were isolated from the edges of lesions. The pathogen was identified as Colletotrichum siamense by morphological characters and multi-locus phylogenetic analyses with ITS region, CHS-1, ACT, TUB2 and ApMat gene sequences. This is the first report of C. siamense causing anthracnose on avocado fruits during storage in China.
查看更多>>摘要：Downy mildew disease in cucurbits is a major constraint to sustainable production of cucurbits in India. The pathogen is known to perpetuate as active mycelium, sporangia and oospores. But in India, the oospores were not reported to play an active role in survival of the pathogen. A little is known about the complete life cycle of P. cubensis, thus, in this study an attempt was made to determine whether the pathogen form oospore under Indian conditions. A survey was undertaken in major cucumber growing regions of Indian Punjab and leaf samples showing symptoms of downy mildew infection were collected. The average size of oospore of P. cubensis ranged from 24 to 28 mu m in diameter. The oospores were yellow to light brown in colour with smooth thick outerwall. Species specific primers corresponding to Cytochrome oxidase subunit 2 (COX-2) gene were further used for molecular identification and confirmation of the fungus. Ludhiana, MW855102 (Ldh10) and Sangrur, MW855103 (SC6) isolates shared maximum nucleotide identity i.e 98.96 per cent (%) with the P. cubensis isolates from Germany and Malaysia. This is the first morphological and molecular evidence of occurrence of oospores of P. cubensis in India. These evidences suggest that, oospores can survive as overwintering stage under Indian conditions and can thus play an important role in causation of the disease.
查看更多>>摘要：A step-by-step laboratory procedure was used to identify the optimal configuration of a tower-shaped trailed sprayer intended for application in vertical shoot trellised vineyards. Different fan settings, air-conveyor orientation, and nozzle configuration were tested for their effect on both airflow pattern and vertical spray distribution. The optimal airflow rate at the fan outlet and the airflow velocity pattern at crop target distance were identified for different fan settings obtained by the combination of two fan gear speeds and three Power Take Off speeds (450, 500 and 540 rev min-1). The difference in the airflow pattern between factory air deflector settings and the adjusted ones was tested. Once the optimal fan setting was selected, the use of 12 or 16 active nozzles and 4 nozzle types was also tested. The optimal vertical spray profiles were determined based on defined thresholds of i) coefficient of variation, ii) amount of spray liquid lost above the target height and iii) two symmetry indices. The low fan gear speed combined with PTO set at 450 rev min(-1) result in the best option to reduce and obtain adequate air velocities. The adjustment of deflectors allowed to exactly match the spray to the canopy target height. Concurrently, the use of 12 nozzles drastically reduced the spray losses above the target height. Finally, 4 configurations out of 18, featured by the combination of a different nozzle type and number of active nozzles, met all the criteria set for optimal vertical spray profile.
查看更多>>摘要：Vascular wilt diseases caused by fungal and bacterial pathogens are the most damaging plant diseases that affect both annual crops and woody perennials. Soil-borne fungus, bacteria, and oomycetes infect the roots and penetrate the water-conducting xylem vessels, where they proliferate and block water and mineral transfer. To control this group of pathogens, several approaches have been conducted such as chemical, genetic, and bio-logical measures. However, genetic and biological approaches are the only effective alternatives to control this pathogen in a sustainable eco-production context. Among all biological control, arbuscular mycorrhizal fungi (AMF) are currently a promising new approach to control soil-borne pathogens. The current state of knowledge on the effect of AMF on vascular wilt diseases and interactions of vascular wilt pathogens with their host plants during the last 20 years is discussed in this review, with a focus on Verticillium, Fusarium, and Bacterial wilts. This review discusses also host defense responses against this group of diseases. The majority of studies used Rhizophagus irregularis and Funneliformis mosseae species to investigate the AMF effect. These AMF species improved plant resilience to environmental and transplanted challenges by stimulating root development, plant growth and development, and improving tolerance to soil-borne pathogens. The dual inoculation of AMF and Pseudomonas fluorescens and Trichoderma sp. has been found as the most efficient biocontrol agents against vascular wilt diseases.
NSTL
Elsevier