scholarly journals First Report of Frog Skin Disease in Cassava (Manihot esculenta) in Venezuela

Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1285-1285 ◽  
Author(s):  
E. I. Chaparro-Martínez ◽  
G. Trujillo-Pinto
Keyword(s):  
South America ◽  
Manihot Esculenta ◽  
Enzyme Linked Immunosorbent Assay ◽  
Stem Cuttings ◽  
Manihot Esculenta Crantz ◽  
First Report ◽  
Average Temperature ◽  
Foliar Symptoms ◽  
Viral Particles ◽  
Long Stem

Frogskin disease (FSD) is a disease of clonally propagated cassava (Manihot esculenta Crantz) and has been reported to reduce cassava yields significantly in South America (1). FSD is caused by an uncharacterized virus that is restricted to South America. The evidence indicates FSD is transmitted by stem cuttings and graft (3). However, little information is available on its distribution and incidence in Venezuela. Eighty-seven samples with virus-like symptoms were collected with the help of technical staff and producers in cassava-producing states: Amazonas (1 sample), Aragua (7 samples), Barinas (35 samples), Cojedes (8 samples), Monagas (19 samples), and Portuguesa (17 samples). In these states, the average daytime temperature was 26°C, but the average was higher (>28°C) during the dry season. Samples were collected during the rainy season because high temperatures and dry field conditions appeared to suppress symptom expression, while cooler conditions tended to favor symptom development (2). Roots of sampled cassava plants were examined for the presence of FSD. A single 70- to 80-cm-long stem cutting was taken from each plant and subdivided into four pieces. Two pieces were used as rootstocks in graft-inoculation tests with Secundina scions for FSD detection, and two pieces were potted in sterilized soil to be used in other tests. All potted and grafted plants were kept in the Vegetable Virology Laboratory of the Faculty of Agronomy (Universidad Central de Venezuela), at an average temperature of 24°C and 80% relative humidity. FSD-infected plants were identified by mosaic symptoms on Secundina scions and the presence of 80-nm spherical viral particles. Most FSD-infected cultivars expressed only root symptoms. However, in the case of Secundina cvs. MCOL 22 and MCOL 113, foliar symptoms were also detected (1). FSD was found in a simple infection in one cassava sample from Aragua State (14.3% incidence, 1 of 7 samples) and in four cassava samples from Barinas State (11.4% incidence, 4 of 35 samples) associated with Cassava virus X (detected by double-antibody sandwich enzyme-linked immunosorbent assay). To our knowledge, this is the first report of FSD detection in Venezuela. References: (1) E. A. Frison et al. Informe Anual. CIAT, Cali, Colombia, 1995. (2) B. L. Nolt et al. Plant Pathol. 41:384, 1992. (3) Technical Guidelines for the Safe Movement of Cassava Rome. FAO/IBPGR. p. 10-27, 1991.

scholarly journals Corrin-based chemosensors for the ASSURED detection of endogenous cyanide

2015 ◽  
Vol 13 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Felix Zelder ◽  
Lucas Tivana
Keyword(s):  
South America ◽  
Manihot Esculenta ◽  
Staple Food ◽  
Manihot Esculenta Crantz

Cassava (Manihot esculenta Crantz) is a staple food for more than 500 million people, especially in Africa and South America.

scholarly journals Manihot Esculenta (Euphorbiaceae), A New Alien Species In Italy

Hacquetia ◽  
2014 ◽  
Vol 13 (2) ◽  
pp. 355-357 ◽  
Author(s):  
Adriano Stinca ◽  
Giuseppe D’Auria ◽  
Riccardo Motti
Keyword(s):  
South America ◽  
Alien Species ◽  
Manihot Esculenta ◽  
Manihot Esculenta Crantz ◽  
Invasive Status ◽  
First Time

Abstract In the present work the presence of Manihot esculenta Crantz is reported for the first time for Italy and Europe, a neophyte native to South America: ecology and invasive status are presented.

Evaluation of the performance of cassava (Manihot esculenta Crantz) when grown from inverted stem cuttings

1978 ◽  
Vol 90 (1) ◽  
pp. 149-156 ◽  
Author(s):  
I. C. Onwueme
Keyword(s):  
Field Experiment ◽  
Leaf Area ◽  
Manihot Esculenta ◽  
Unit Area ◽  
Lower Percentage ◽  
Stem Cuttings ◽  
Total Leaf Area ◽  
Manihot Esculenta Crantz ◽  
Below Ground ◽  
Number Of Leaves

SUMMARYIn order to investigate the characteristics of inverted cassava plantings, seven-node cuttings were planted upright or inverted, and such that four nodes of each cutting were within the soil in a glasshouse. They were observed for 7 weeks. The inverted cuttings sprouted less rapidly, but the percentage of the cuttings which eventually sprouted was not decreased. The inverted cuttings produced more sprouts than the upright ones, and a greater percentage of their sprouts were produced below ground than for the upright cuttings. At 5 and 7 weeks, the total leaf area per cutting was less for the inverted cuttings. The number of leaves per cutting did not differ between the treatments.In a field experiment comparing upright and inverted stem pieces, field emergence and tubering were slower in the inverted cuttings. Yield per plant and per unit area was significantly lower for the inverted cuttings. In the upright planting, most of the tubers originated at the lowest extremity of the cutting and formed a compact bunch there. For the inverted planting, most of the tubers arose from the shallower-lying submerged nodes, but the tubers did not form a compact bunch. The inverted planting had a lower percentage of its tubers lying along the ridge. In a few of the inverted plantings, but not in the upright, the bases of some stems became tuberous. The treatments did not differ with respect to mean tuber length, radius of spread of the tuber tip, and the number of major stems per plant.

scholarly journals Occurrences of whiteflies (Hemiptera: Aleyrodidae) on cassava (Manihot esculenta Crantz) crops under field conditions in the State of Rio de Janeiro, Brazil.

2012 ◽  
Vol 5 (1) ◽  
pp. 78-79 ◽  
Author(s):  
Rodrigo da Silva Alonso ◽  
Francisco Racca-Filho ◽  
Aurino Florêncio de Lima
Keyword(s):  
South America ◽  
Manihot Esculenta ◽  
Rio De Janeiro ◽  
Morphological Characters ◽  
Neotropical Region ◽  
The State ◽  
Economic Losses ◽  
Manihot Esculenta Crantz ◽  
First Time ◽  
Second World

Brazil is the second world largest cassava producer and the largest one in South America. The aleyrodids, commonly known as whiteflies, are pests that affect cassava crops and might induce economic losses, due to high infestation levels. The objective of this work was to survey the whitefly species that occur feeding on cassava (Manihot esculenta Crantz) crops in the State of Rio de Janeiro. Leaf samplings were conducted in five municipalities of the State and the species identification was realised according to morphological characters of the 4th instar nymphs. Among the 16 aleyrodid species described feeding on cassava in the Neotropical region, Aleurothrixus aepim (Göeldi), Bemisia tuberculata Bondar and Trialeurodes manihoti (Bondar) were identified occurring in the State. The species B. tuberculata and T. manihoti  are reported for the first time in the State of Rio de Janeiro, where they were found feeding on cassava crops. Ocorrências de Moscas-Brancas (Hemiptera: Aleyrodidae) em Lavouras de Mandioca (Manihot esculenta Crantz) sob Condições de Campo no Estado do Rio de Janeiro, Brasil. Resumo. O Brasil é o segundo maior produtor mundial de mandioca e o maior produtor do continente sul americano. Os aleirodídeos, insetos comumente conhecidos como moscas-brancas, são pragas que acometem esta cultura e podem causar prejuízos econômicos, em decorrência de altas infestações. O objetivo deste trabalho foi levantar as espécies de moscas-brancas que ocorrem na cultura da mandioca (Manihot esculenta Crantz) no Estado do Rio de Janeiro. Foram realizadas amostragens de folhas em lavouras localizadas em cinco municípios do estado e a identificação das espécies foi feita por caracteres morfológicos das ninfas de 4.º instar. Das 16 espécies de aleirodídeos descritas na região Neotropical em plantas de mandioca, três foram identificadas ocorrendo no estado, Aleurothrixus aepim (Göeldi), Bemisia tuberculata Bondar e Trialeurodes manihoti (Bondar). É registrada pela primeira vez no estado a presença das espécies B. tuberculata  e T. manihoti em lavouras de mandioca.

scholarly journals First Report of the Cymbidium Mosaic Potexvirus (CymMV) Infecting the Terrestrial Orchid Phaius tankervilliae in Costa Rica

Plant Disease ◽  
1998 ◽  
Vol 82 (10) ◽  
pp. 1171-1171 ◽  
Author(s):  
L. Moreira ◽  
W. Villalobos ◽  
H. T. Hsu ◽  
E. Rodríguez-Cerezo ◽  
C. Rivera
Keyword(s):  
Costa Rica ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Central Valley ◽  
Major Protein ◽  
Terrestrial Orchid ◽  
First Report ◽  
Foliar Symptoms ◽  
Viral Particles ◽  
Sds Page

In 1996, plants of the terrestrial orchid Phaius tankervilliae from a nursery in the Central Valley of Costa Rica were observed with mild to severe foliar symptoms of chlorotic streak. No differences were observed in growth, bulb production, flowers, or flowering time between symptomatic and asymptomatic plants, except the symptomatic plants had earlier senescence. Occasionally, the flowers displayed symptoms of chlorosis and white rings in the sepals. Extracts from symptomatic leaves were concentrated by differential centrifugation and analyzed after sucrose gradients. Negative staining of fractions from gradients from symptomatic plants showed the presence of filamentous viral particles 500 by 17 nm. Purified particles contained a single major protein of about 28 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and a single RNA of about 7 kb, which is greater than the 6.2 kb reported (GenBank). These data suggest the presence of a potexvirus in symptomatic plants (1,2). In enzyme-linked immunosorbent assays, symptomatic plants reacted strongly with antiserum specific for Cymbidium mosaic potexvirus (CymMV). This is the first report of CymMV in P. tankervilliae in Costa Rica. References: (1) J. A. Frowd and J. H. Tremaine. Phytopathology 67:43, 1977. (2) H. T. Hsu et al. Phytopathology 82:491, 1992.

scholarly journals First Report of Dothichiza caroliniana Causing Double Spot on Highbush Blueberry in South America

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1685-1685 ◽  
Author(s):  
O. Baino ◽  
A. C. Ramallo ◽  
S. Hongn ◽  
J. C. Ramallo
Keyword(s):  
South America ◽  
Vaccinium Corymbosum ◽  
Necrotic Area ◽  
Highbush Blueberry ◽  
First Report ◽  
Leaf Spots ◽  
Foliar Symptoms ◽  
Leaf Surfaces ◽  
Pathogenicity Tests ◽  
White Mycelium

A foliar disease affecting Jewell, Emerald, and O'Neal cultivars of highbush blueberry (Vaccinium corymbosum L.) was observed in commercial plantings in Tucuman, Argentina during February 2007. Typical symptoms were circular leaf spots that were 10 to 15 mm in diameter, light to dark brown with dark reddish borders, and frequently exhibiting a secondary necrotic area around the original spot. The final appearance was a large necrotic area surrounding a pale, smaller spot. On the abaxial leaf surfaces, white mycelia grew from the border of the initial or enlarged spots toward the healthy tissues. Frequently, black pycnidia bearing an amber rubbery cirrhi were observed. Fewer pycnidia were observed on the adaxial leaf lesions. The fungus was isolated by transferring cirrhi from affected leaves onto petri plates containing potato dextrose agar (PDA). Plates were incubated in darkness at 27°C and light brown concentric colonies with an aerial, effuse, white mycelium developed. After 5 days, dark brown cirrhi emerged from pycnidia in culture. Pycnidiospores were obtuse, hyaline, 1-celled (7 × 2 μm), and grew from the base of pycnidia on short conidiophores. Pycnidia were black, conical, obovoid, averaged 110 × 70 μm wide, and were lightly immersed in the mycelium. Pathogenicity tests were performed by spraying a 106 conidia/ml suspension on leaves of nine blueberry plants (cv. Jewell). Plants were incubated in a moist chamber at 25 to 29°C with a 12-h photoperiod. After 5 weeks, all inoculated leaves had foliar symptoms similar to the lesions previously observed in the field. Reisolation of the fungus completed Koch's postulates. Noninoculated leaves did not develop foliar symptoms. Morphological and cultural characteristics of the fungus conformed to the descriptions of Dothichiza caroliniana (Demaree & M.S. Wilcox) reported to cause “double spot” in blueberry (1,2). Symptoms were consistent with those described for double spot disease (2). To our knowledge, this is the first report of D. caroliniana on blueberry in South America. References: (1) J. B. Demaree and M. Wilcox. Phytopathology, 37:490, 1947. (2) R. D. Milholland. Double spot. Page 17 in: Compendium of Blueberry and Cranberry Diseases. F. L. Caruso and D. C. Ramsdell, eds. The American Phytopathological Society, St. Paul, MN 1995.

scholarly journals First Report of a 16SrIII-L Phytoplasma Associated with Frogskin Disease in Cassava (Manihot esculenta Crantz) in Brazil

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 153-153 ◽  
Author(s):  
S. A. S. Oliveira ◽  
E. F. M. Abreu ◽  
T. S. Araújo ◽  
E. J. Oliveira ◽  
E. C. Andrade ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Nested Pcr ◽  
Manihot Esculenta ◽  
Dsrna Virus ◽  
Raw Material ◽  
Rrna Gene ◽  
Manihot Esculenta Crantz ◽  
First Report ◽  
Ctab Method

Cassava (Manihot esculenta Crantz) is a major staple crop in developing countries and a large source of raw material for industrial purposes as flour, starch, and ethanol. In July 2012, 24 cassava genotypes (corresponding to 1.85% of the accessions) with typical symptoms of frogskin disease (CFSD) were observed in one of the maintenance areas of the Brazilian Cassava Germplasm (located at Embrapa Cassava & Fruits, Cruz das Almas, Bahia State, Brazil). All diseased plants were asymptomatic on the aboveground parts (leaves and stem). However, for accessions BGM 880, BGM 1094, BGM 1100, BGM 1212, BGM 1218, and BGM 1526, all roots showed a woody appearance, thickened cork-like peel with opaque aspect, and coalescent lip-like slits in a honeycomb pattern. Based on literature description, two pathogens could be associated with CFSD: a dsRNA virus (belonging to family Reoviridae) and a 16SrIII-L phytoplasma (1). To investigate the presence of phytoplasma associated with the CFSD symptoms, total DNA was extracted from 0.5 g of root tissue collected from both symptomatic and asymptomatic roots by scratching the secondary vessel at the center of the cassava root with a CTAB method. The nested PCR was carried out using phytoplasma-specific primer set P1/Tint followed by R16F2n/R16R2, targeting the 16S rRNA gene sequence of 1.2 kb in length, for the final reaction (4). No phytoplasma was detected in asymptomatic cassava roots that were sampled from the same field. A posterior extraction of total RNA was made but no dsRNA was noticed on the agarose gel, and reaction of RT-PCR with specific primers (2) had no amplification. In order to characterize the strains, the 1.2-kb amplicon was digested with BamHI, MseI, MspI, KpnI, and TaqI endonucleases. The resulting patterns indicated that the symptomatic accessions were infected with a phytoplasma belonging to the 16SrIII group, sharing similarities with pseudo gel mapping from the reference strain of Peach X-Disease Phytoplasma (GenBank Accession No. L33733). Nested PCR products from accessions BGM 1526 and BGM 1212 were purified and sequenced by Macrogen, (Seoul, South Korea) in both directions, manually edited, and the consensus sequences were deposited in the NCBI database (GenBank Accession Nos. KF019184 and KF019185). Phylogenetic studies were conducted based on maximum parsimony, neighbor-joining, and maximum likelihood analysis for 16S rRNA. The phytoplasma 16S rRNA gene sequences from both strains had 99% identity (P < 0.0001) with the 16SrIII-L CFSD phytoplasma (EU346761 and AY737647), described by Alvarez et al. (1) infecting cassava in Colombia. To our knowledge, this is the first report of a phytoplasma associated with Cassava Frogskin Disease in Brazil, where only the dsRNA virus was recognized as causing this symptom (3). This is not likely to be an isolated case, and possibly more cassava plants are infected with this phytoplasma in Brazil. Due to the difficulties to observe the symptoms at the field level, this could be an emerging disease in that country. References: (1) E. Alvarez et al. Plant. Dis. 93:1139, 2009. (2) L. A. Calvert et al. J. Phytopathol. 156:647, 2008. (3) L. S. Poltroniere et al. Comun. Tec., Belem-PA. 006:2p, 1999. (4) C. D. Smart et al. Appl. Environ. Microb. 62:2988, 1996.

Description of a new Amblystira (Hemiptera: Heteroptera: Tingidae) from Argentina with a key to the South American species of the genus

Zootaxa ◽  
2010 ◽  
Vol 2675 (1) ◽  
pp. 65 ◽  
Author(s):  
SARA I. MONTEMAYOR
Keyword(s):  
Life Cycle ◽  
South America ◽  
Manihot Esculenta ◽  
New World ◽  
South American ◽  
The South ◽  
South American Species ◽  
Manihot Esculenta Crantz ◽  
Important Crop

Amblystira Stål is a new world American genus comprising nineteen species, most of them distributed in Central and South America. Nine species have been recorded from South America, and only Amblystira silvicola Drake is known from Argentina (Drake & Ruhoff, 1965). Members of the genus are dark, the cephalic spines are generally absent or poorly developed, the hood is absent, the paranota are scarcely developed or absent as well as the lateral pronotal carinae, the discoidal area is short not reaching the middle of the hemelytra, and the costal area is slender. The only member of the genus that has been recorded as a pest is Amblystira machalana Van Duzee, commonly known as “black lacebug”, which feeds on cassava, Manihot esculenta Crantz, an important crop of South America. Arias & Belloti (2003) studied the life cycle, behavior, and damage caused by A. machalana on M. esculenta. (Guilbert, 2005) described the fifth instar of Amblystira peltogyne Drake & Hambleton.

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