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Epidemic Roller Coaster: Maize Stunt Disease in Nicaragua
Abstract
The incidence of maize stunt diseases, or achaparramiento, rose in Nicaragua from an insignificant level to national crisis proportions, then declined to insignificant levels again, all in the space of 10 yr. The 3 pathogens that cause achaparramiento, corn stunt spiroplasma, maize bushy stunt phytoplasma, and maize ray ado fino virus are transmitted by the corn leafhopper, Dalbulus maidis (De- Long & Wolcott). Vector populations did not change sufficiently over time to explain the epidemic pattern. Nor did changes in the varieties of maize that farmers used cause the differential expression of disease symptoms during this period. The most likely explanation of the epidemic pattern is an abrupt 3- to 4-yr increase in irrigated maize production during the dry season, when maize was not grown traditionally. Irrigated maize provided a temporal bridge for the pathogens, which then were transmitted to rainy season plantings and caused epidemic disease incidence throughout the country. This explanation demonstrates the powerful impact that governmental agricultural policies, in this case to strongly promote dry-season maize production, can have on crop pest and pathogen problems.
... Corn stunt is one of the most significant diseases affecting maize crop due to its high potential to cause yield losses [1][2][3]. The increasing prevalence of corn stunt in the Americas [2][3][4][5] after its first detection [6,7] is a major constraint for corn production. The mollicute Spiroplasma kunkelii Whitcomb is the most common pathogen associated with corn stunt, although Maize bushy stunt phytoplasma (MBSP) and Maize rayado fino virus (MRFV) might be found as well [3,4,8]. ...
... The increasing prevalence of corn stunt in the Americas [2][3][4][5] after its first detection [6,7] is a major constraint for corn production. The mollicute Spiroplasma kunkelii Whitcomb is the most common pathogen associated with corn stunt, although Maize bushy stunt phytoplasma (MBSP) and Maize rayado fino virus (MRFV) might be found as well [3,4,8]. These pathogens are transmitted only by a few leafhopper species, especially Dalbulus maidis (DeLong), the main vector species [8][9][10][11] due to its distribution [8,9,11,12] and transmission efficiency of S. kunkelii [13,14]. ...
The corn leafhopper Dalbulus maidis is the main vector of the pathogens that cause corn stunt, a major disease of maize in the Americas. In line with plant resistance being an efficient tool to control diseases, the findings of a previous work showed that some corn hybrids are resistant to D. maidis. In this work, we assessed the probing behavior of D. maidis on susceptible and resistant corn hybrids using EPG (Electrical Penetration Graph) technology. Feeding of fifteen-day-old, non-inoculative females was recorded for 20 hours, with access to hybrids DK390, DK670, DK79-10, and DK72-10. Compared to the susceptible hybrid DK670, the other hybrids shifted D. maidis probing behavior in a way consistent with plant resistance to insects. This shift consisted of a higher number of probes of short duration, difficulties in attaining phloem ingestion and increase in xylem ingestion. In addition to this common shift in probing behavior, a phloem-located resistance factor was inferred in DK72- 10 based on the longer time spent in phloem conditioning to attain phloem ingestion. In contrast, DK390 expressed the highest level of mesophyll and phloem-based resistance, in both cases seen with repeated attempts of short duration, a behavior typically associated with failed attempts to ingest. These findings support and are consistent with previous research, providing useful information to characterize maize hybrids resistant to D. maidis, and consequently to corn stunt.
... Corn stunt is one of the most significant diseases affecting maize crop in the Americas due to its high potential to cause yield losses [1, 2, 3]. The increasing prevalence of corn stunt in the Americas [2,4,5] after its first detection [6, 7] is a major constraint for corn production. The mollicute Spiroplasma kunkelii Whitcomb is the pathogen mostly associated with corn stunt [3,4,8]. ...
... The increasing prevalence of corn stunt in the Americas [2,4,5] after its first detection [6, 7] is a major constraint for corn production. The mollicute Spiroplasma kunkelii Whitcomb is the pathogen mostly associated with corn stunt [3,4,8]. This pathogen is transmitted only by a few leafhopper species, being Dalbulus maidis (DeLong) the main vector species [8,9,10,11] due to its distribution [8,9,11, 12] and transmission efficiency of S. kunkelii [13,14]. ...
The corn leafhopper Dalbulus maidis is the main vector of the pathogens that cause corn stunt, a major disease of maize in the Americas. As host resistance is an efficient tool to control diseases, the findings of a previous report showed that some corn hybrids are resistant to D. maidis . In this work, we assessed the probing behavior of D. maidis on susceptible and resistant corn hybrids using EPG (Electrical Penetration Graph) technology. Fifteen-day-old females were monitored for 20 hours, with access to hybrids DK390, DK670, DK79-10, and DK72-10. Hybrids DK390 and DK72-10 showed resistance to D. maidis in phloem, since insects feeding on these hybrids presented more salivation events in phloem without subsequent ingestion, which are seen as failed attempts to ingest. A reduction of the total duration of phloem ingestion was observed, and accordingly of the time spent by insects with access to these hybrids on xylem ingestion. The hybrid DK390 also had mesophyll resistance, seen as less probing time and a higher number of probes of short duration. These findings support and are consistent with previous research, providing useful information to characterize maize hybrids resistant to D. maidis , and so to corn stunt.
... Maize bushy stunt (MBS) is the most important disease that decreases maize production especially in Latin American cultivations, where it can decrease the production and yield of the crop up to 100% (Jones & Medina, 2020). The disease has been reported in the United States, Costa Rica (Harrison et al., 1996), Mexico (Pérez-López et al., 2016), Nicaragua (Hruska et al., 1996), Belize (Henríquez et al., 1999), Colombia (Duduk et al., 2008), and Brazil (Bedendo et al., 1997). In Peru, MBS has been reported in the departments of Ancash and Ayacucho (Nault et al., 1979(Nault et al., , 1981 and in the Junin region (Hodgetts et al., 2009;Nipah et al., 2007). ...
Corn plants showing symptoms of midribs chlorosis, and leaf reddening, short internodes, ear proliferation, and plant growth reduction were collected in Peru from fields in nine localities in the provinces of Huancayo, Chupaca, and Jauja in the Junín region, and tested to verify phytoplasma presence and identity. Primers amplifying the phytoplasma ribosomal 16S and ribosomal protein genes were used. The phytoplasma presence was detected in symptomatic samples from all the surveyed areas. The sequencing of the obtained amplicons indicated the presence of ‘ Candidatus Phytoplasma asteris’ and ‘ Ca . P. pruni ’-related strains. A BLASTn search of sequenced genes showed that the two ‘ Candidatus Phytoplasma’ strains identified in corn shares 100% and 99.82% identity with the ‘ Ca. P. asteris ’ strains from maize and 99.92% and 99.55% with ‘Ca. P. pruni ’-related strains, respectively. The RFLP analyses allowed to enclose these phytoplasma strains in the 16SrI-B and 16SrIII-J subgroups; however, the two phytoplasmas were, in some cases, present in mixed infection. The 16SrIII-J phytoplasma is for the first time reported associated with the maize bushy stunt disease and this represent a relevant information for the disease epidemiology towards its appropriate management in the affected area.
... So far, two predominant phytoplasma groups have been reported to trigger remarkable symptom development in maize plants worldwide, which are as follows: Maize bushy stunt phytoplasma (16SrI-B) and Stolbur phytoplasma (16SrXII-A). Maize bushy stunt phytoplasma was described in Latin America [14], Vietnam [15], Brazil [16], Peru [17], Nicaragua [18], Costa Rica [19], Belize [20], Colombia [21], and Mexico [22] while Stolbur phytoplasma was reported to have a narrow spread in Serbia [23], Bosnia and Herzegovina [24], Bulgaria [25], and Italy [26]. Moreover, the Bermudagrass white leaf phytoplasma (BGWL) ('Ca. ...
To determine the phytoplasma infection in maize fields in Van (Turkey), we collected 15 samples from plants, with or without symptoms, specific to the phytoplasma agent. A two-step PCR test was performed on all the samples using an appropriate primer set designed according to the 16S rRNA gene region, out of which three samples displayed a DNA fragment of about 1250 bp. Further, one positive fragment was randomly selected and bacterially cloned. The sequencing of this recombinant plasmid revealed that the corresponding 16S rRNA genomic sequence was 1247 bp-long, and according to the BLAST analysis, it was closely related to the 16S rRNA gene of the phytoplasma. Based on the results of the iPhyclassifier and Virtual Restriction Fragment Length Polymorphism (V-RFLP) analyses, the agent of phytoplasma disease in the symptomatic maize plant ('Ca. P. trifolii') was identified as 16SrVI-A of 'Candidatus Phytoplasma trifolii'. Based on the phylogenetic relationship and a similarity coefficient of 1.00, the Clover proliferation group (Acc. No. MK372596) was clustered with the Canadian reference isolate (AY390261). We declare that this research is the first report indicating maize plant to be an alternate host of 'Ca. P. trifolii' in Turkey (Van province) and our information is crucial for a better understanding of the epidemiology of the associated agent.
... Corn Stunt is one of the most significant diseases affecting maize crop in the Americas, because of its high prevalence and its potential to cause yield losses in endemic areas [1][2][3]. Following its initial detection [4,5], its prevalence has increased in the Americas [2,[6][7][8]. Corn Stunt disease was first confirmed in the subtropical region of Argentina during the 1990/ 91 crop season [9]. High disease prevalence was later reported in this region in 1996/97, 2001/ 02, 2006/07 and 2010/11 crop seasons [7,8,10], and isolated symptomatic plants may be found occasionally in temperate areas of Argentina [8,[11][12][13]. ...
Corn Stunt is an important disease in the Americas due to it high prevalence and the yield reductions that can cause when present. However, changes in the presence of this disease across years hampers the effective identification of resistant genotypes to this disease. To avoid the limitations of phenotypic selection under natural pressure, this research aimed to devise an effective strategy to screen disease-resistant genotypes in the absence of high and constant natural pressures. To do so, we investigated the presence of antixenosis and antibiosis as components of resistance to the vector Dalbulus maidis as well as resistance to the pathogen Spiroplasma kunkelii under artificial inoculation conditions in four maize hybrids. The hybrids shown differences in their levels of resistance and target organisms, either the insect vector or the pathogen. Antixenosis and antibiosis to D. maidis were observed in DK72-10. Resistance to S. kunkelii by DK79-10 was seen as a delayed onset of symptoms, and DKB390 showed antixenosis to D. maidis and resistance to S. kunkelii. An association between symptom severity and yield reduction was found, but not between accumulation of pathogen S. kunkelii and symptom severity nor yield. In conclusion, the proposed methodology was efficacious and can aid in the screening of resistant genotypes in breeding programs to reduce the impact of Corn Stunt disease, ensuring that hybrids with good resistance level will be planted by farmers whenever disease occurs.
... La enfermedad conocida como achaparramiento del maíz es causada por un complejo de patógenos. Entre este complejo se tiene al espiroplasma del achaparramiento del maíz (Spiroplasma kunkelii), causante de la enfermedad denominada "Corn Stunt Spriroplasm" (CSS); el fitoplasma causante del enanismo arbustivo del maíz o "Maize Bushy Stunt" (MBS) y el Virus del Rayado Fino del MAÍZ (MRFV) (Hruska et al., 1996;Ebbert et al., 2001). Estos patógenos son transmitidos por el salta hojas o chicharrita Dalbulus maidis (Canale et al., 2018;Oliveira et al., 2011). ...
Un clima adverso ha sido característico en todo el país, cambios más recientes derivados entre otros factores del calentamiento global y la crisis del precio de los alimentos han aumentado la vulnerabilidad y el riesgo de las comunidades rurales y de los productores causando un impacto significativo en la seguridad alimentaria y la pobreza extrema. Sequías al inicio de los ciclos de siembra y en los momentos críticos del cultivo (floración, llenado de granos), lluvias más intensas en algunos períodos de cultivo y la aparición de nuevas plagas están causando trastornos importantes en la productividad y la seguridad alimentaria. Reportes de investigaciones recientes, incluyendo estudios de modelación, señalan que el impacto del calentamiento global podría causar significativas disminuciones en el rendimiento del arroz, maíz y otros cultivos en los próximos treinta años. El cambio climático complica aún más este escenario. Todos los sistemas de producción de grano se caracterizan por sus bajos rendimientos, lo que se refleja en la media nacional. Esto, entre otras causas, se debe a diversos factores bióticos y abióticos, además de técnicas de manejo inadecuadas en lo que respecta a densidad, control de malezas, plagas y fertilización. A pesar de estos bajos rendimientos, el promedio del rendimiento en el Arco Seco se ha incrementado en los últimos años con alzas y bajas alternadas (coincidiendo con la ausencia o presencia de problemas con la distribución de lluvias). El desarrollo de cultivares y prácticas agronómicas que mitiguen el efecto de la sequía y mejoren la eficiencia de las prácticas agronómicas producirá beneficios económicos para los agricultores, y contribuirá a mitigar el efecto del cambio climático al reducir el impacto de la sequía, junto con la aplicación de cantidades excesivas de fertilizantes y otros insumos derivados del petróleo. Se presenta un resumen de las recomendaciones agronómicas para mejorar la productividad del cultivo, así como alternativas para mitigar los principales problemas que se presentan en la producción del cultivo en el país.
... Corn stunt disease has been the most important limiting factor of corn production in the Caribbean and the Americas, including the United States, Mexico, and Central and South America during the 19th and 20th centuries [19][20][21][22][23]. Recently, corn stunt disease has resurfaced, as symptoms were observed in native corn varieties grown in southeast Puebla, Mexico [24]. ...
Over 700 plant diseases identified as vector-borne negatively impact plant health and food security globally. The pest control of vector-borne diseases in agricultural settings is in urgent need of more effective tools. Ongoing research in genetics, molecular biology, physiology, and vector behavior has begun to unravel new insights into the transmission of phytopathogens by their insect vectors. However, the intricate mechanisms involved in phytopathogen transmission for certain pathosystems warrant further investigation. In this review, we propose the corn stunt pathosystem (Zea mays–Spiroplasma kunkelii–Dalbulus maidis) as an ideal model for dissecting the molecular determinants and mechanisms underpinning the persistent transmission of a mollicute by its specialist insect vector to an economically important monocotyledonous crop. Corn stunt is the most important disease of corn in the Americas and the Caribbean, where it causes the severe stunting of corn plants and can result in up to 100% yield loss. A comprehensive study of the corn stunt disease system will pave the way for the discovery of novel molecular targets for genetic pest control targeting either the insect vector or the phytopathogen.
Direct and indirect injury caused by Dalbulus maidis (Hemiptera: Cicadellidae) in corn is an ever-increasing concern in Brazil and other corn-producing countries of the Americas. This highly efficient vector transmits corn stunting pathogens and is of economic concern in the Neotropics, including temperate regions where epidemic outbreaks are now common. Despite the progress made so far, Brazilian corn growers continue to struggle with this pest and its associated pathosystem. In this review, we gathered relevant and updated information on the bioecology, population dynamics, and damaging potential of D. maidis. Our goal was to better understand its intimate association and complex interactions with the host crop and transmitted pathogens. Based on available scientific literature, we identified factors which explain the recent increase in D. maidis occurrence in South America, including the cultivation of corn during multiple growing seasons, overlapping of susceptible crops, and widespread use of genetically modified hybrids. The reasons for the overall inefficiency of current suppression strategies aimed at this pest are also summarized. Finally, a management program for D. maidis and corn stunt disease is proposed, combining strategies such as eradicating volunteer corn, reducing the planting period, using tolerant hybrids, and applying chemical and/or fungal insecticides. Prospects regarding the pest’s status are also outlined. Overall, the information presented here will serve as a decision-making guide within Brazilian and South American corn production systems, as well as paving the way for devising novel strategies aimed at suppressing D. maidis populations and limiting the spread of corn stunt disease.
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