Susceptibility of Fuerte avocado fruit at various stages of growth, to infection by anthracnose and stem end rot fungi

1978 ◽  
Vol 18 (90) ◽  
pp. 158 ◽  
Author(s):  
RA Peterson
Keyword(s):  
Field Experiments ◽  
Colletotrichum Gloeosporioides ◽  
Natural Infection ◽  
Persea Americana ◽  
Glomerella Cingulata ◽  
Stages Of Growth ◽  
Small Fruit ◽  
Avocado Fruit ◽  
Time Of Infection

In a series of field experiments, Fuerte avocado fruit (Persea americana) were susceptible to infection by Glomerella cingulata var. minor (Colletotrichum gloeosporioides var, minor) and Dothiorella aromatics, from set until harvest. Natural infection was detected from December to May and field inoculations demonstrated that small fruit in October were also susceptible. The time of infection varied with the season and was related to rainfall incidence. The significance of this finding is discussed.

Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith
Keyword(s):  
Oryza Sativa ◽  
Glycine Max ◽  
Fungal Pathogens ◽  
Liquid Culture ◽  
Field Experiments ◽  
Colletotrichum Gloeosporioides ◽  
Pathogenic Fungus ◽  
Field Tests ◽  
Wide Range ◽  
Growing Region

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.

scholarly journals Characterization and Pathogenicity of Botryosphaeriaceae Species Obtained from Avocado Trees with Branch Canker and Dieback and from Avocado Fruit with Stem End Rot in Chile

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 996-1005 ◽  
Author(s):  
Ana L. Valencia ◽  
Pilar M. Gil ◽  
Bernardo A. Latorre ◽  
I. Marlene Rosales
Keyword(s):  
Vascular System ◽  
Persea Americana ◽  
Effective Control ◽  
Future Research ◽  
Severe Drought ◽  
Internal Transcribed Spacer Region ◽  
Avocado Fruit ◽  
Hass Avocado ◽  
Botryosphaeriaceae Species ◽  
Branch Canker

Several species of the Botryosphaeriaceae family have been associated with branch canker, dieback, and stem end rot in avocado (Persea americana Mill.). In Chile, the incidence of diseases affecting the avocado tree increased from 2011 to 2016, which coincided with a severe drought that affected avocado production. Moreover, distant countries importing avocados from Chile also reported an increase of stem end rot of ripe avocados. Therefore, the aims of this study were to identify the pathogen species associated with branch canker, dieback, and stem end rot of avocado in Chile and to study their pathogenicity. This study was conducted between 2015 and 2016 in ‘Hass’ avocado orchards located in the main avocado-producing regions in Chile. A diverse collection of fungal species was recovered from both necrotic woody tissue and necrotic tissue on harvested ripe fruit. On the basis of morphology and phylogenetic analyses of the internal transcribed spacer region (ITS1-5.8S-ITS2) and the translation elongation factor 1-α (TEF1-α) gene, eight species in the Botryosphaeriaceae family were identified: Diplodia mutila, D. pseudoseriata, D. seriata, Dothiorella iberica, Lasiodiplodia theobromae, Neofusicoccum australe, N. nonquaesitum, and N. parvum. For each of these species, pathogenicity studies were conducted on 1-year-old healthy Hass avocado plants. All isolates produced brown gum exudate and caused necrosis in the vascular system 3 weeks after inoculation. N. nonquaesitum, N. parvum, and D. pseudoseriata were the most virulent species. Necrotic lesions and cavities with white mycelia near the peduncle union were observed on Hass avocado fruit inoculated postharvest. L. theobromae, N. australe, and N. parvum were significantly more virulent than the other tested species in the Botryosphaeriaceae family. This study identified and characterized the pathogenicity of Botryosphaeriaceae species in Chile, which will prove useful to future research on these pathogens directed at establishing effective control strategies in avocado.

scholarly journals First Report of Black Spots on Avocado Fruit Caused by Neofusicoccum parvum in Mexico

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287 ◽  
Author(s):  
E. Molina-Gayosso ◽  
H. V. Silva-Rojas ◽  
S. García-Morales ◽  
G. Avila-Quezada
Keyword(s):  
Average Length ◽  
Black Spot ◽  
Persea Americana ◽  
Universal Primers ◽  
Internal Transcribed Spacer Region ◽  
Pathogenic Potential ◽  
Neofusicoccum Parvum ◽  
First Report ◽  
Black Spots ◽  
Avocado Fruit

Avocado (Persea americana L.) production for export markets has increased in Mexico during the past 10 years. The production system, however, is affected by several sanitation factors, including diseases. During the spring of 2009, smooth, black, circular spots were noted on the surface of avocado fruit. A study was conducted during the winter of 2010 to ascertain the etiology and identify the fungus associated with black spot symptoms on avocado fruit in orchards of Nuevo Parangaricutiro County (19°25′00″ and 102°07′43″) in Michoacan, Mexico. Several fungal isolates were obtained on potato dextrose agar (PDA) from the margin of lesions on immature fruit. The internal transcribed spacer region (ITS) of the rDNA from representative isolates was sequenced with universal primers ITS5 and ITS4 (2). BLAST searches in GenBank showed 100% similarity of the nucleotide sequences with Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips, GenBank Accession Nos. GU188001 to GU188007 and GU187985 to GU187987. A representative nucleotide sequence of this region was deposited in GenBank under the Accession No. JN203129. Strains of N. parvum produced aerial and compact mycelium on acidified PDA, the anamorph state of Botryosphaeria parva. Mycelium was initially white, turning gradually gray to black. Conidia were one celled, hyaline, ellipsoidal to fusiform, externally smooth, thin walled, nonseptate, with one or two septa with age, and an average length and width of 14.5 (9.5 to 19) × 5.8 (4.0 to 7.2) μm (n = 100). Pathogenicity tests were conducted with six avocado fruit cv. Hass. Fruit were inoculated at three evenly spaced locations on the fruit surface, either by wounding the tissue with a needle that had been dipped in a conidial mass from an 8-day-old monoconidial culture of N. parvum strain CIAD-021-11 or by placing 5 μl of 1 × 106 conidia ml–1 suspension on each inoculation site. Inoculated fruit were maintained in a moist chamber at 25°C for 2 weeks. Black lesions appeared on all wounded sites 2 days postinoculation (dpi) and on unwounded sites 4 dpi. The delay of symptom development was likely due to penetration through the lenticels, which took longer to initiate infection. No symptoms were observed in the control fruit. The pathogen was reisolated from the lesions of all inoculated fruit, thus fulfilling Koch's postulates. The results confirmed the pathogenic potential of this fungus and indicated its possible involvement in the etiology of black spot on avocado fruit. N. parvum is a cosmopolitan, plurivorous pathogen causing disease in several hosts of economic importance, such as grapes and kiwi, as well as causing stem-end rot of avocado fruit in New Zealand (1) and avocado twigs in Spain (3). To our knowledge, this is the first report of N. parvum causing black spots on avocado fruit in Mexico. References: (1) W. F. T. Hartill et al. N.Z.J. Crop Hortic. Sci. 30:249. 2002. (2) T. J. White et al. Page: 315 in: PCR Protocols: A Guide to Methods and Application. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990. (3) T. Zea-Bonilla et al. Plant Dis. 91:1052, 2007.

scholarly journals Caracterização da agressividade de isolados de Colletotrichum de maracujá amarelo com marcadores bioquímico, fisiológico e molecular

2007 ◽  
Vol 32 (4) ◽  
pp. 318-328 ◽  
Author(s):  
Luiz Carlos C. Almeida ◽  
Rildo S.B. Coêlho
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Glomerella Cingulata ◽  
Colletotrichum Spp

A antracnose é a doença pós-colheita mais importante do maracujá amarelo, cujo agente etiológico, no Brasil, foi identificado como Colletotrichum gloeosporioides. Visando caracterizar o patógeno, foram obtidos 33 isolados de três regiões produtoras do estado de Pernambuco. Critérios morfológicos como cor de colônia, forma e dimensão de conídios, a produção de peritécio e o uso de primers específicos para C. acutatum, C. gloeosporioides e "Colletotrichum de Passiflora" permitiram identificar Glomerella cingulata patótipo 1, G. cingulata patótipo 2, Colletotrichum sp. de Passiflora e Colletotrichum sp. de maracujá amarelo. Inoculações em maracujá amarelo possibilitaram separar os isolados em dois grupos, um de agressividade alta (GA-1) e outro de agressividade baixa (GA-2). Os marcadores bioquímicos como atividade enzimática amilolítica, celulolítica, lipolítica e proteolítica assim como o marcador fisiológico crescimento micelial não separaram os isolados pela agressividade. O padrão de marcas geradas pela amplificação dos DNAs dos isolados usando primers RAPD evidenciou que os isolados do GA-1 variaram menos geneticamente entre si do que os isolados do GA-2, demonstrando que os do GA-1 evoluíram mais recentemente. A amplificação do DNA dos isolados com o primer OPA-9 gerou um marcador que possibilitou caracterizar 85,7% dos isolados do GA-1 e também alguns isolados do GA-2 com agressividade próxima às dos isolados do GA-1, e por isto o primer OPA-9 pode ser usado para caracterizar isolados de Colletotrichum spp. de alta agressividade em programa de resistência genética.

scholarly journals Yield and quality of two hulless barley varieties after inoculation with Fusarium culmorum

2019 ◽  
Vol 65 (1) ◽  
pp. 17-22
Author(s):  
Ivana Políšenská ◽  
Kateřina Vaculová ◽  
Ondřej Jirsa ◽  
Irena Sedláčková ◽  
Jan Frydrych
Keyword(s):  
Field Experiments ◽  
Starch Content ◽  
Natural Infection ◽  
Fusarium Culmorum ◽  
Fiber Content ◽  
Content Increase ◽  
Hulless Barley ◽  
Yield And Quality

The effect of F. culmorum inoculation on the yield and quality of grain of AF Cesar and AF Lucius barley varieties was monitored. Field experiments were conducted between 2015-2017 at two locations. In grain harvested from plots grown under natural infection conditions, the deoxynivalenol content was very low. Inoculation caused a decline in germination, a certain reduction in yield and a change in some qualitative parameters (reduction in protein and fiber content, increase in starch content), but the effect of inoculation was weak and significantly influenced by the environment and the variety. The β-glucan content was not affected by inoculation. The varieties differed significantly from each other in β-glucan content (AF Cesar > AF Lucius). The deoxynivalenol content of both varieties was comparable after the inoculation while it differed under conditions of the natural infection (AF Cesar < AF Lucius).

scholarly journals PENENTUAN KORELASI TINGKAT KEMATANGAN BUAH ALPUKAT (Persea americana mill) TERHADAP GRAVITASI SPESIFIK

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Jusuf Wahyudi ◽  
Roni Herdian Saputra
Keyword(s):  
Specific Gravity ◽  
Room Temperature ◽  
Time Variable ◽  
Persea Americana ◽  
Maturity Level ◽  
Social Community ◽  
Ripening Time ◽  
Long Day ◽  
Avocado Fruit ◽  
Fruit Maturity

Social community need to food in general and horticulture in particular from year to year continues to increase along with the growth of population too.  This will result an increased need for nutrition and consumption patterns including avocado fruit contains many nutrients needed by human. In this study, 36 ( Thirty six ) Pleces of avocado which each take the data GSp is left at room temperature and then contolled every day to find pleces that correspond to each code.  After a long day and that all avocado fruit over ripe the find corelation value ( r ) between GSP value ( Variable Xi ) with ripening time     ( Variable Yi ). From this study obtainable correlation value between GSp value avocado fruit    (Variable Xi) with ripening time ( Variable Yi ), r = 0,71.   From this value r get t aritmetic = 5,336. In the real level a = 0,05 and dk = 30-2 = 3428 get ttable = 2, 048 it turs out t aritmetic  > t table 5,336,1 > 2,048 so that Ha accepted and Ho benied or correlation between specific gravity value with increase avocado fruit maturity significant.  Key words : Avocado Fruit, Specific Gravity, correlation, Maturity Level.

Avocado fruit— Persea americana

Exotic Fruits ◽  
2018 ◽  
pp. 37-48 ◽  
Author(s):  
Elena Hurtado-Fernández ◽  
Alberto Fernández-Gutiérrez ◽  
Alegría Carrasco-Pancorbo
Keyword(s):  
Persea Americana ◽  
Avocado Fruit

Effects of Organic Arsenical Herbicides on Cotton Response and Chemical Residues

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 37-40 ◽  
Author(s):  
R. S. Baker ◽  
H. F. Arle ◽  
J. H. Miller ◽  
J. T. Holstun
Keyword(s):  
Gossypium Hirsutum ◽  
Cotton Plant ◽  
Topical Application ◽  
Field Experiments ◽  
Arsenic Content ◽  
Stages Of Growth ◽  
Chemical Residues ◽  
Coverage Rates ◽  
Methods Of Application ◽  
Topical Applications

The influence of timing and method of application of sodium or disodium salts of methanearsonic acid (MAA) on cotton (Gossypium hirsutum L.) response, arsenic content of seed, and arsenic content of soils, was studied in field experiments in California, Arizona, and Mississippi. Methods of application consisted of directed and topical sprays. Directed sprays were applied to cover the small weeds in the drill row with a minimum of contact on cotton leaves more than 2 to 3 inches above the ground. Topical sprays were applied from nozzles positioned over the cotton in such a way that the entire cotton plant was subject to coverage. Rates of application were either 2 or 3 lb/A of the salts, and either two or three applications were made to treated plots. Cotton appeared highly tolerant to directed applications. A topical application to cotton 2 to 4 inches slightly reduced yields, but topical applications made at later stages of growth caused progressively severe reductions in yields and delayed maturity. The arsenic content of cottonseed from treated plots was not significantly higher than in that from untreated checks providing that applications were restricted to prebloom stages. Either directed or topical applications made during the blooming stage resulted in detectable increases of arsenic in the cottonseed. The effect of the treatments on arsenic content of soils was relatively small in comparison with natural levels, but the effect was detectable at one of the three locations.

A new avocado pest in Central America (Lepidoptera: Tortricidae) with a key to Lepidoptera larvae threatening avocados in California

Zootaxa ◽  
2011 ◽  
Vol 3137 (1) ◽  
pp. 31 ◽  
Author(s):  
TODD M. GILLIGAN ◽  
JOHN W. BROWN ◽  
MARK S. HODDLE
Keyword(s):  
Life History ◽  
New Species ◽  
Central America ◽  
Secondary Structures ◽  
Persea Americana ◽  
Female Genitalia ◽  
Complete List ◽  
Male And Female ◽  
Avocado Fruit ◽  
Potential Pest

Cryptaspasma perseana Gilligan and Brown, new species, is described and illustrated from Mexico and Guatemala. This species is a potential pest of the fruit of cultivated avocado, Persea americana (Lauraceae). Images of adults, male secondary structures, male and female genitalia, eggs, larvae, and pupae are provided. Details of the life history are reviewed. We provide characters to differentiate this pest from the most common avocado fruit pest in the region, Stenoma catenifer (Walsingham) (Elachistidae), and a key to identify Lepidoptera larvae threatening avocado in California. In addition, we provide a complete list of tortricids documented from different avocado varieties worldwide.

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