Occurrence of Maize rayado fino virus in Maize in Argentina

Abstract

Symptoms of fine chlorotic stipple-striping of the veins, chlorosis, numerous dots and stripes, formation of holes in the leaf blade, and ears reduced in size, bearing few grains, were observed in maize crops in Tafí del Valle (Tucumán Province), Orán, El Galpón (Salta Province), Tilcara and Yaví (Jujuy Province), the subtropical area of northwest Argentina where the leafhopper vector Dalbulus maidis (DeLong & Wolcott) is present. Maize rayado fino virus (MRFV) was detected in these samples by a positive reaction in double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) using an AGDIA kit. Electron microscopy revealed abundant isometric particles about 30 nm in diameter in the cytoplasm and vacuoles of phloem cells and xylem parenchyma cells. The virus was also detected by reverse transcription polymerase chain reaction (RT-PCR) using a primer pair MRFV-09/MRFV-10. Primers and PCR conditions were as previously described (1). Virus amplification was observed only in samples from symptomatic plants. In 1981 (2), the presence of MRFV in Argentina was revealed by serological assay in plants from temperate central areas. No further reports were released since then. This is the first evidence of MRFV in subtropical areas of Argentina and identification of the virus by combining DAS-ELISA, particle size, relation with plant tissues, and RTPCR. References: (1) R. W. Hammond et al. J. Gen. Virol. 78:3153, 1997. (2) S. F. Nome et al. RIA XIX:257, 1984.

Endomycobiome associated with females of the planthopper Delphacodes kuscheli (Hemiptera: Delphacidae): A metabarcoding approach

“…This planthopper is a phloem feeder ( Brentassi, 2004 ; Brentassi and Remes Lenicov, 2007 ; Brentassi et al., 2019 ) and is the most important natural vector of Mal de Río Cuarto virus (MRCV) (Fijivirus, Reoviridae) ( Remes Lenicov et al., 1985 ). MRCV seriously affects maize ( Zea mays L.) production in northern and central provinces of Argentina ( Lenardón et al., 1998 ; Giménez Pecci et al., 2012 ) and also has been detected in Uruguay ( Ornaghi et al., 1999 ). Previous studies of D. kuscheli specimens demonstrated that the abdomen of nymphs and adults of both sexes and morphs (macropterous and brachypterous), as well as oocytes, contained YLS, indicating they are vertically transmitted ( Brentassi et al., 2014 ).…”

Growth Inhibition ofBeauveria bassianaby Bacteria Isolated from the Cuticular Surface of the Corn Leafhopper,Dalbulus maidisand the Planthopper,Delphacodes kuscheli,Two Important Vectors of Maize Pathogens

“…The corn leafhopper Dalbulus maidis (De Long and Wolcott) (Hemiptera: Cicadellidae) is widely distributed in tropical areas of the Americas, from southern USA to temperate zones of Argentina ( Virla et al 1990/1991 ; Giménez Pecci et al 2002 ), and it is considered one of the most damaging species to corn due to its role as a vector of maize rayado fino virus, Spiroplasma kunkelii, and maize bushy stunt mycoplasm. These three pathogens, alone or in combination, are the ethiological agents of corn stunt, a disease that causes economic losses to corn crops in Mexico and Central and South America, and has been detected in restricted areas in the north of Argentina in 1990 ( Giménez Pecci et al 2000 ). Among the delphacid pests of maize is the planthopper, Delphacodes kuscheli Fennah (Hemiptera: Delphacidae) a native species of Argentina that has been reported as a vector of Mal de Río Cuarto virus ( Remes Lenicov et al 1985 ; Remes Lenicov and Virla 1999 ).…”

Distribution of Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae) and incidence of maize rayado fino virus and Candidatus Phytoplasma asteris in corn succession planting systems

“…The loss of productivity caused by maize bushy stunt phytoplasma is expected and known from the scientific literature. 8,13 The other measures (grain per row, number of rows and weight of 100 grains) also reflected the losses caused by diseases transmitted by D. maidis. Our results showed that the potential damage caused by diseases transmitted by D. maidis was not negligible and should be considered even at low insect densities.…”

“…With the development of the disease, the points coalesce and form lines along the veins. 13 Early infections can lead to reduced growth and abortion of floral buds. 14 Despite the records of these diseases in tropical and temperate areas, the climatic variables that affect their incidence and severity remain poorly understood.…”

“…Maize rayado fino virus causes small chlorotic spots on the leaves. With the development of the disease, the points coalesce and form lines along the veins 13 . Early infections can lead to reduced growth and abortion of floral buds 14 .…”