Alternative hosts play an important role on the survival of plant pathogenic bacteria. They represent sources of inoculum for new infections; therefore, the identification of potential alternative hosts and the study of their interaction with plant pathogens are essential for the development of effective disease management strategies. The objective of this study was to investigate the interaction between

Two field-collected tomato plants, with severe and mild tomato leaf curl disease symptoms, were shown to be infected with tomato leaf curl New Delhi virus. The plant with severe symptoms was shown to additionally contain tobacco leaf curl betasatellite (TobLCuB). Inoculation of Nicotiana benthamiana plants with the cloned components showed the severe symptoms to be due to the presence of TobLCuB. A

Citrus in Bhutan is cultivated on steep hillsides up to ~ 1550 m above sea level (ASL). Since 2000, the Asiatic form of huanglongbing caused by ‘Candidatus Liberibacter asiaticus’ (CLas) has led to dramatic losses of trees below 1200 m ASL. Surveys prior to this study indicated a low incidence of the disease and the psyllid Diaphorina citri (the principal vector of the pathogen), above 1200 m ASL,

Nothopassalora personata is a cosmopolitan plant pathogenic fungus that causes late leaf spot (LLS) of peanut, the main foliar diseases of this crop. The disease emerged during the last decade in the USA and Argentina. Severely affected plants are early defoliated and yield is decreased by 40–50%. During the last decades, effective LLS management worldwide has been achieved using chemical fungicides

Phytoplasmas are associated with the lethal disease of coconut palms in Tanzania (LDT). It is a destructive lethal yellowing-type syndrome (LYTS) exhibiting differences in losses between the southern districts and the northern districts. To explain these differences, the existence of variable pathogenic strains of the LDT phytoplasma was investigated using ribosomal RNA gene PCR primers. A total of

Neonectria ditissima, the causal agent of European Canker and Neonectria fruit rot, is a quarantine apple pathogen in Brazil, restricted to some production areas of Rio Grande do Sul, Santa Catarina, and Paraná states. The quarantine rests on a product certification based on the absence of symptoms but it is not known whether the pathogen could be moving around in quiescent infections. In this work

Metagenomic approaches in conjunction with high-throughput sequencing (HTS) have been employed for the discovery of novel plant-associated viral species, including members of the Geminiviridae family. In the present work, the HTS strategy allowed for the identification of genetically divergent tomato-associated geminivirus 1 (TaGV1) isolates from tomato and table beet in Brasília-DF, Brazil. The complete

Cercospora leaf blight and purple seed stain are caused by Cercospora kikuchii and other Cercospora spp. The fungus can infect leaves and seeds on soybean, and the disease is controlled with fungicides. In Brazil, the intensive use of fungicides on soybean to control other diseases such as soybean rust has exerted resistance selection pressure on all fungal pathogens that attack in the crop. In this

In most developing countries, farmers lack sufficient supply of certified or healthy potato seed tubers. Hence, they often plant their own saved ware potato tubers, a practice that is known to contribute to spread and increase the prevalence of plant viruses. In this study, we proposed options for managing the virus based on the knowledge obtained from surveys of virus prevalence and distribution in

A survey of Sugarcane yellow leaf virus (SCYLV) was conducted in northern Argentina in 2015 and 2016 using tissue blot immunoassay (TBIA). Results showed plant infection rates of 2.2–86.7% in sugarcane commercial fields from different growing areas. Percentage of infected leaves varied among cultivars and areas. NA 05–860 was the most infected cultivar (86.7% incidence). Virus genotypic diversity of

Though an experimental host of Xylella fastidiosa, tobacco (Nicotiana tabacum) is an excellent plant model for biological and functional genomics studies of host-pathogen interactions involving X. fastidiosa. Symptoms induced by X. fastidiosa subsp. pauca on tobacco have been characterized, but severity assessment relies on an ordinal scale developed for symptoms on citrus. We designed a standard area

Witches’ broom disease of lime (WBDL), associated with ‘Candidatus Phytoplasma aurantifolia,’ is a serious disease of acid lime in Southern Iran. In order to characterize ‘Ca. P. aurantifolia’ strains, a multilocus sequence analysis protocol was developed based on different genomic loci, including 16S rRNA, 16S-23S rRNA intergenic spacer (IS), ribosomal protein genes rpl22 and rps3, cell division protein

Plants of beggarticks (Bidens pilosa L.), honeyweed (Leonurus sibiricus L.), and citrus (Citrus ssp.) trees exhibiting phyllody and virescence, leaf distortion, and yellow shoots symptoms, respectively, were found in orchards at the state of Sao Paulo. Based on PCR assays, computer-simulated RFLP, and phylogenetic analyses, it was confirmed that these plants were infected with a phytoplasma of the

Huanglongbing (HLB), the most important citrus disease worldwide, is associated with bacteria transmitted by the Asian citrus psyllid (ACP) preferably through new shoots present in the canopy. In a commercial citrus plant, the vegetative growth of the scion is influenced by the rootstock variety in which it is grafted. Although all commercial citrus varieties planted in recent years are susceptible

One of the biggest challenges of wheat production worldwide is to overcome fungal diseases, and among these is Fusarium head blight (FHB) caused mainly by the Fusarium graminearum species complex (FGSC). The occurrence of FHB can lead to contamination of grains with mycotoxins, which are harmful to human and animal health. In South America, in addition to F. graminearum sensu stricto (F. graminearum)

Root-knot nematodes (RKNs; Meloidogyne spp.) are a major constraint of pepper (Capsicum annuum L.) crops worldwide. In Mexico, Sinaloa State is one of the main producers of pepper; however, there is little information available on the distribution, prevalence, and incidence of RKN on this crop. Identification of RKN species and estimation of the epidemiological factors are important to design its management

Pepper mild mottle virus (PMMoV), a tobamovirus, has been reported worldwide infecting, especially, pepper plants. In this study, seven new PMMoV isolates were identified in symptomatic pepper plants collected in four departments of Peru. The majority of these isolates induced severe symptoms, including mottle, in susceptible pepper plants. Inoculation on pepper plants carrying four known functional

Drench applications of systemic acquired resistance (SAR) inducing compounds acibenzolar-s-methyl (ASM) and thiamethoxam (THIA) may contribute for the control of citrus canker, caused by Xanthomonas citri subsp. citri. Here, we report the results of a 3-year field experiment on the effect of drench applications of two SAR-inducing compounds, applied alone or in combination with copper oxychloride (CuOX)

Effective quantification of Calonectria ilicicola in naturally infested soils is critical for evaluating and validating control measures for managing red crown rot disease in soybean. Counting of microsclerotia has been used to quantify this pathogen, but the method is laborious and time-consuming to process large numbers of soil samples using wet sieving. To overcome these issues, we developed and

Avocado (Persea americana), an important fruit crop, is under threat from an invasive disease, laurel wilt. The pathogen, Raffaelea lauricola, spreads rapidly in the xylem of infected trees and causes a lethal vascular wilt. A previous study showed that variation in susceptibility to the disease exists among different races of avocado, with the West Indian race being most susceptible. To help elucidate

The spatiotemporal spread of citrus huanglongbing (HLB, ex greening) in Minas Gerais (MG) state, Brazil, was analyzed since its first detection in 2005. Data on the amount of eradicated plants per orchard were gathered from the georeferenced database of the state’s official HLB monitoring program. In total, 1487 orchards (118 municipalities) have been inspected yearly up to 2018. Overall, 57.2% (64

Common bean (Phaseolus vulgaris L.) is one of the most widely grown legumes in the world. Although the crop has high yield potential, average yields in Brazil are low due to several diseases. Angular leaf spot (ALS), caused by Pseudocercospora griseola, is among the most important diseases. A set of 81 accessions from the Instituto Agronômico (IAC, Campinas, SP) germplasm bank were evaluated for ALS

Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense (Foc), tropical race 4 (TR4), is one of the most devastating diseases, thus control of this disease is an urgent need in banana production. Streptomyces morookaensis strain Sm4-1986 significantly inhibited mycelial growth and spore germination of pathogen Foc-TR4. Chrome Azurol S assay showed that the strain Sm4-1986 is able to produce

Podosphaera xanthii is presently considered as one of the powdery mildew fungi with the broadest host range. Confusion is caused by taxonomical and nomenclatural changes of the host plants and the fungal parasite. Based on the list of powdery mildews from Taiwan from 1998, an updated list of host plants of P. xanthii in this country is presented. New hosts from Taiwan are wild and horticultural herbs

In the past 15 years, the global citrus industry has experienced significant losses in the fruit production, largely due to the huanglongbing (HLB). This bacterial disease impairs water and nutrient uptake by roots causing nutritional disorders and, reciprocally, metabolic imbalances associated to oxidative stress and carbohydrate distribution in trees. The sustainability of optimum yield and fruit

Citrus is one of the most important fruit crops globally and rising incidence of citrus yellow vein clearing virus (CYVCV) in citrus orchards is an increasing concern in India. CYVCV and Indian citrus ringspot virus (ICRSV) are assigned to the only two known species in the genus Mandarivirus. Both viruses naturally infect several citrus plants. ICRSV produces ringspots symptoms in Kinnow mandarin,

Intensive agriculture requires large inputs of chemicals to avoid losses caused by pathogen infections. Exploring the rhizosphere of plants, which is an area with enormous abundance and diversity of microorganisms, represents a promising strategy to protect plants from pathogens in a sustainable way. Recent studies revealed the importance of soil microbiome in the process of natural plant defense and

Spot blotch, caused by the pathogen Bipolaris sorokiniana, is an important foliar disease of wheat in warm and humid regions worldwide. The fungal virulence factor ToxA interacts with Tsn1 in wheat and leads to a susceptible reaction. ToxA has been found in B. sorokiniana populations of Australia, the USA, and India, and here we report its occurrence in Mexico, based on analysis of a collection of

Grape production in the Serra Gaúcha region, south of Brazil, is severily constrained by several diseases such as the decline and death syndrome caused grapevine trunk (fungal) diseases (GTDs) and the grapevine leafroll-associated virus (GLRaV). As pathogens induce changes in leaf tissue that modify the reflectance, the spectral signature of asymptomatic and symptomatic grapevine leaves infected by

Citrus huanglongbing (HLB) represents a major threat to citriculture due to its rapid spread, difficulty of control, severe yield losses, and substantial increases in production costs in HLB-affected orchards. Successful management depends on detailed knowledge of the epidemiology of this disease, which is associated with phloem-limited bacteria of the genus Candidatus Liberibacter that are transmitted

Soybean seed infected with Colletotrichum truncatum is an important source of primary inoculum for anthracnose epidemics. Based on differences in the GAPDH gene sequences of Colletotrichum species, one pair of species-specific primers, CtruncF1/CtruncR1, was designed to accurately detect C. truncatum in soybean seed samples. The primers amplified only a single PCR band of 211 bp from C. truncatum.

Arabica coffee (Coffea arabica L.) is a native from Africa, particularly from Ethiopia. Previously of little concern to Ethiopian farmers, coffee leaf rust (CLR), caused by the fungus Hemileia vastatrix, is an emergent disease globally. To update the status of CLR, a large survey was conducted in 405 coffee fields across nine production zones of Oromia and Southern Nations Nationalities and Peoples

Huanglongbing (HLB) is considered the most devastating bacterial disease in citriculture. It is caused by the phloem-limited α-proteobacterium ‘Candidatus Liberibacter asiaticus’ (CLas). All citrus varieties are susceptible to HLB and many studies have been conducted in an attempt to identify potential targets involved in bacterial virulence and pathogenicity mechanisms. One of the most important virulence

Maize bushy stunt and corn stunt have emerged among the most important diseases of maize in Brazil. To evaluate the single or dual presence of the phytoplasma and spiroplasma associated with corn stunting diseases, maize samples were collected across several locations in four Brazilian states. Multiplex PCR was performed for simultaneous detection of the bacteria. Eighty-nine out of 100 samples were

Citrus growers in several states of Brazil, but mainly in São Paulo (SP), have battled during 60 years against citrus canker (Xanthomonas citri subsp. citri) using exclusion and eradication methods. Since its first detection in 1957, the eradication program has undergone many modifications and efforts were made to suppress rather than eradicate the disease. When the eradication protocols became less

Citrus Huanglongbing (HLB) is currently the most devastating citrus disease worldwide. HLB, first identified in Asia, and its insect vector, the Asian citrus psyllid (ACP), are quickly spreading in citrus-producing areas in South America and North America. The main challenges for HLB control include the phloem-limited biology of Candidatus Liberibacter spp., the causal agent of HLB, which shields the

The Chinese citrus industry is facing an unprecedented challenge from citrus Huanglongbing (HLB). As no resistant commercial citrus varieties and no curable chemicals are available so far, it is still the “no. 1 threat” to Chinese citrus industry. This review article outlines the current status of the disease prevalence and measures recommended and adopted for the prevention and control of HLB in China

An extensive survey was carried out in the Dominican Republic in order to monitor the prevalence of the three most widespread BSV species: Banana streak OL virus (BSOLV), Banana streak GF virus (BGFV) and Banana streak IM virus (BSIMV), in Macho x Hembra (MxH) and FHIA-21 plantains and in Cavendish dessert banana throughout all banana-producing areas. This survey led to the first detection of BSVs

The use of resistance inducers may be a tool to assist in the management of citrus diseases. However, knowledge about how some inducers, such as the benzothiadiazoles, promote gene expression from the pathways involved in induced resistance and alter plant development are lacking. In this work, we evaluated the effect of the acibenzolar-S-methyl (ASM) on gene expression from the biosynthetic pathways

Plasmids are a major source of horizontal gene transfer among bacteria contributing to their evolution and ecology. The known collection of plasmids carried by the plant pathogen Xylella fastidiosa increases as new strains from different origins and hosts are sampled and sequenced. Here we performed an extensive comparison of 61 publicly available sequences annotated as plasmids belonging to 38 X.

Product and byproducts of the citrus industry are destined mainly for export and they play a significant role in the Brazilian economy. The major threats to citrus production and business include weather conditions (abiotic stress) and plant disease epidemics (biotic stress), especially bacterial diseases. Historical examples of devastating bacterial diseases that have shaped and changed radically

Citrus is one of the most ancient fruit crops cultivated in the world. For many countries, citrus production is an important source of revenues. However, despite the richness of citrus production worldwide, fruit yields are constantly threatened by diseases that cause serious economic and social impacts to growers and consumers. One such example is citrus canker, a disease that affects all commercial

Phytophthora sojae causes root and stem rot of soybeans. In Argentina, this pathogen has shown dramatic shifts in pathotype variability since its first discovery during the 1970s. The aim of this study was to report the presence and distribution of different pathotypes of P. sojae isolates from 2013 to 2015 in the southeast of Buenos Aires Province in Argentina. Isolates were obtained from diseased

Maize yellow mosaic virus, provisionally referred to MaYMV, is a novel polerovirus reported in China, Brazil, Ecuador, and more recently in Africa. Despite the broad distribution of this potentially emerging virus, information is lacking on transmission, symptomatology, and possible interaction with other maize viruses. As MaYMV belongs to the genus Polerovirus, circulative transmission by aphids was

Phytophthora blight is the most devastating disease for pepper (Capsicum annuum L.) production and is caused by Phytophthora capsici. Current management strategies are not effective. Our study assessed the multi-trait effects of Paenibacillus polymyxa, which suppresses Phytophthora blight and promotes plant growth in pepper plants. A total of 82 bacterial strains isolated from rhizosphere soil of pepper

Despite efforts of research to establish best nutrient management practices in HLB-affected citrus orchards, there are still doubts about the contribution of such strategies to minimizing losses caused by the disease in the citrus industry. We evaluated the effects of micronutrient (Zn, Mn, and/or Cu) supply and ‘Candidatus Liberibacter asiaticus’ (CLas) infection on physiological and growth traits

This study was conducted to evaluate inhibitory effect of natamycin against three isolates of Sclerotinia sclerotiorum, the causal agent of carrot white mold in postharvest phase. The results showed that natamycin was able to markedly decrease radial growth and sclerogenesis of three isolates of the pathogen. In addition, natamycin significantly reduced myceliogenic and carpogenic germinations of sclerotia

Huanglongbing (HLB) is a severe disease of citrus caused by the bacterium Candidatus Liberibacter. In America, the most common species is Candidatus Liberibacter asiaticus (CLas). In a previous study of the Citrus-HLB pathosystem, our group found differences in CLas multiplication in a population of hybrids obtained by hybridization between Citrus sunki Hort. Ex Tan. and Poncirus trifoliata (L.) Raf

Interactions between insects and plant pathogens have been more enthusiastically studied in the recent decade, especially those relationships which takes the insects as vectors. The spectrum of these interactions ranges from mutualistic to pathogenic. The length of the co-evolutionary process will determine whether a microorganism shares a friend or a foe relationship with its host, and a friendship

Penja pepper (Piper nigrum) produced in Cameroon has long been recognized for its exceptional organoleptic quality. The pepper vine is grown using a support tree (Spondias mombin) in Cameroon. A root disease is associated with plant deaths in both plants. The disease symptoms are characterized by collar cracking and gummosis and the disease was tentatively identified as Armillaria root rot. In this

Citrus mosaic virus (CiMV) and navel orange infectious mottling virus (NIMV) are considered strains of satsuma dwarf virus (SDV). To understand the distribution of different isolates of SDV in China, a field survey was conducted, which allowed for the detection of CiMV and NIMV in citrus plants in Zhejiang and Sichuan provinces, respectively. In the present work, two CiMV isolates, including one named

Root and crown rot (RCR) of dry bean is a disease complex caused by soil-borne pathogens that can limit bean production in Zambia. Identifying the primary pathogen in the complex would facilitate the control as well as breeding for resistance to the disease. Plant tissue samples and DNA embedded FTA® Cards were collected to isolate, detect and molecularly identify RCR pathogens using genus/species

Citrus cultivation is challenging due to the plethora of abiotic and biotic stresses faced by the crop. In recent years, production has been severely affected by diseases such as citrus canker and huanglongbing (HLB). Disease management is hampered as there is no field resistance to these diseases in any of the important commercially planted varieties. Traditionally, conventional breeding approaches

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the natural vector of the Huanglongbing (HLB) pathogen that presents an unparalleled challenge to citrus production. RNA interference (RNAi) has already shown great potential for insect pest management owing to its high specificity. RNAi technique relies on the delivery of exogenous double-stranded RNAs (dsRNAs) that target essential

In wheat, leaf rust caused by Puccinia triticina Eriks is a major disease that causes major losses in production. In the present study, microsatellite or SSR (simple sequence repeat) markers were developed for P. triticina using the transcriptome data obtained during wheat-P. triticina interactions. A total of 37,268 P. triticina differentially expressed transcripts were obtained in the comparative

Avocado Branch Dieback and Wilting (ABDW) was recently reported on West-Indian avocado (Persea americana var. americana) orchards in the Serrania de Perija, Colombia. This disease is caused by Bionectria pseudochroleuca and transmitted by ambrosia beetles. In this work we estimated the potential distribution of ABDW to map avocado-growing areas at risk of ABDW in Colombia and Venezuela. Disease occurrence

Leaf blight disease in coconut (LBC) caused by Lasiodiplodia theobromae leads to early defoliation and loss of bunches, which negatively impacts coconut fruit yield. The etiology of LBC in Brazil needs to be updated based on modern tools such as DNA sequencing and phylogenetic analysis. A phylogenetic tree using ITS and TEF-1α genes in combination with morphology showed L. theobromae as the most common

Plant pathogenic Xanthomonas species attack a wide range of agriculture crops and is capable of surviving on weeds. In this study, Xanthomonas strains obtained from weeds grown withing vegetable crop fields in the state of Pernambuco, Northeast Brazil, were identified. Bacterial colonies resembling Xanthomonas were obtained from Aeollanthus suaveolens (strain CCRMXe03), Amaranthus lividus (CCRMXe01

This review summarizes the current status of citrus canker in the United States. The disease is present in Florida, Louisiana, and Texas. In Florida, the eradication program ended in 2006 and now citrus canker is endemic to many citrus-growing areas, although it is still possible to find canker-free groves. In endemic areas, the disease is controlled using windbreaks, applying copper-based bactericides