Hélcio Costa

Papaya Diseases and Integrated Control

Diseases are a significant limiting factor for papaya production. The nature and frequency of these diseases depend on local conditions and effective management depends on a thorough knowledge of the pathogen, host plant, environment, and their interaction. The precise identity of the causal agent is of paramount importance, and disease management options must be economical. Assessment of disease incidence or severity, and fruit loss are the key factors in determining the economics of disease management. In general, disease management strategies involve different practices that include plant resistance, and prophylactic and curative measures. The papaya diseases related have diverse etiologies, divided into those with biotic (infectious) and abiotic (noninfectious) etiologies that affect the fruit and those affecting the plant. We have attempted to emphasize procedures for diagnosis and control with detailed information on each. Descriptions of pathogens are provided in sufficient detail to assist professional diagnosticians in making accurate diagnosis. Fungicides used to control many of the diseases described in this chapter are mentioned for information proposes only. Legal restrictions and regulations of fungicide use vary among countries, and regulations within any country are subject to change over time. The information reported has been extracted from the available scientific literature and the authors’ experience, and we hope that this publication will provide a helpful reference to growers, students, and professionals working with papaya.

Occurrence of Tomato chlorosis virus in tomato crops in five Brazilian states

Tomato chlorosis virus (ToCV) is a species in the genus Crinivirus, transmitted by Bemisia tabaci biotype B, first detected in Brazil in 2006 in the county of Sumare, State of Sao Paulo. During the period from 2007 to 2010, RT-PCR analyses followed by nested-PCR with specific primers for ToCV detection, and sequencing of the amplicons, confirmed the presence of this virus in samples of symptomatic tomato plants (Solanum lycopersicum) from crops in counties in the states of Bahia (BA), Espirito Santo (ES), Goias (GO), Minas Gerais (MG), and Rio de Janeiro (RJ). This is the first ToCV report for the states of BA, ES, GO, MG, and RJ, suggesting that this virus is widely disseminated in Brazil.

'Vitoria' pineapple: fusariose resistent cultivar

A importância da fruticultura e em especial da abacaxicultura no agronegocio brasileiro vem aumentando a cada ano. Entre os principais problemas que impedem a obtencao de altos rendimentos da fruta no Brasil esta a fusariose, doenca causada pelo fungo Fusarium subglutinans f.sp. ananas (Sin.: F. guttiforme), com perdas estimadas em 30 a 40% nos frutos e em ate 20% nas mudas. A selecao de variedades resistentes apresenta-se como a alternativa de controle mais eficiente e economica. A cultivar Vitoria, lancada na Fazenda Experimental do Incaper, em Sooretama-ES, em novembro de 2006, e resistente a fusariose e apresenta caracteristicas agronomicas semelhantes ou superiores em relacao as cvs. Perola e Smooth Cayenne (suscetiveis). Os frutos sao de polpa branca (1,5kg), tem elevado teor de acucares (15,8oBrix) e excelente sabor, podendo ser destinados ao mercado de consumo in natura e a agroindustria. Para o Espirito Santo, a cv. Vitoria viabilizou a expansao da area em producao, principalmente na regiao Norte, onde o Governo do Estado, por meio da Secretaria de Estado da Agricultura, Abastecimento, Aquicultura e Pesca (SEAG), do Instituto Capixaba de Pesquisa, Assistencia Tecnica e Extensao Rural (INCAPER), e das Prefeituras Municipais estao estruturando e implementando acoes para o estabelecimento do novo Polo de abacaxi, possibilitara, no minimo, dobrar a produtividade capixaba de abacaxi, passando de aproximadamente 21 t/ha para mais de 50 t/ha. A demanda por mudas da cultivar Vitoria tem sido elevada, e varios laboratorios de cultura de tecidos de plantas no Pais (Bahia, Espirito Santo e Sao Paulo) ja estao produzindo material propagativo. No Espirito Santo, para garantir a producao de mudas da nova cultivar, o Incaper mantem campos de producao, nas suas Fazendas Experimentais de Sooretama (municipio de Sooretama) e de Pacotuba (municipio de Cachoeiro do Itapemirim), para implementar, em cooperacao com as Prefeituras Municipais, Cooperativas e Associacoes de Produtores, campos clonais visando a distribuicao de mudas para os produtores de abacaxi capixabas. REVISTA BRASILEIRA DE FRUTICULTURA

Controle da ferrugem do cafeeiro com base no valor de severidade

O presente trabalho teve por objetivo avaliar o controle da ferrugem do cafeeiro (Coffea arabica) baseando-se no valor de severidade, calculado em funcao das variaveis meteorologicas, molhamento foliar e temperatura media durante o periodo de molhamento. Foram escolhidas duas lavouras de cafe da cultivar Catuai Vermelho, uma com alta carga pendente de frutos (101,5 sacas beneficiadas/ha), com seis anos de idade, localizada no municipio de Coimbra, a 680 m de altitude, na regiao da Zona da Mata de Minas Gerais; e a outra, com carga media de frutos (22,4 sacas beneficiadas/ha), com nove anos de idade, localizada no municipio de Carmo do Paranaiba, a 850 m de altitude, na regiao do Alto Paranaiba do Estado de Minas Gerais. Em Coimbra, quando o valor de severidade da ferrugem (VSF) foi igual a 30, foram feitas duas pulverizacoes com fungicida sistemico, igualando-se as duas aplicacoes de fungicida sistemico do calendario. Em Carmo do Paranaiba, o VSF igual a 49 recomendou apenas uma unica pulverizacao; todos os outros tratamentos demandaram duas aplicacoes de fungicidas sistemicos. A incidencia final de folhas doentes na colheita (11,0%) para todos os tratamentos, nao atingiu o nivel de dano economico ao cafeeiro. Nao houve diferenca na eficiencia de controle dos tratamentos baseados no calendario (duas aplicacoes de fungicidas sistemicos e quatro aplicacoes de fungicida cuprico), duas aplicacoes de fungicida sistemico baseadas na incidencia da doenca (10%) e o sistema baseado no VSF. Portanto, o sistema baseado no VSF foi tao eficiente quanto o calendario, para o controle da ferrugem do cafeeiro, porem com economia de uma pulverizacao, na lavoura com carga media de frutos (Carmo do Paranaiba).

First report and characterization of Fusarium circinatum, the causal agent of pitch canker in Brazil

Pitch canker is one of the most important diseases of pine trees worldwide, including South America. The causal agent of this disease is Fusarium circinatum, a member of the Gibberella fujikuroi complex (GFC). In South America, the species is reported from Colombia, Uruguay and Chile, but is considered a quarantine organism in Brazil. In this study we characterized isolates obtained from symptomatic pine seedlings intercepted in a nursery in Santa Catarina State using phylogenetic analyses, crossings and morphological markers. The Brazilian isolates grouped with reference material in an unique clade and formed fertile perithecia when crossed with reference tester strains. The detailed characterization given here and the availability of tester strains will allow for reliable identification and support monitoring of this important plant pathogen.

A phytoplasma representative of a new subgroup, 16SrXIII-E, associated with Papaya apical curl necrosis

Papaya apical curl necrosis (PACN) has frequently been observed in several Brazilian states. Affected plants exhibit foliar chlorosis, curvature of the apex, shortening of the internodes leading to bunching of the crown leaves, necrosis of the young apical parts, leaf drop, and dieback. Naturally infected plants were sampled and subjected to PCR assays, which confirmed that a phytoplasma was associated with the disease. Sequencing of the 16S rRNA gene, conventional and computer-simulated RFLP analyses, and phylogenetic analysis allowed the determination of the PACN phytoplasma as a representative of a new subgroup, designated 16SrXIII-E. The phytoplasmas of various 16Sr groups, including 16SrI, 16SrII, 16SrX, 16SrXII, and 16SrXVII, are known to be involved in anomalies in papaya plants in several countries. However, the present study reports, for the first time, the occurrence of a 16SrXIII phytoplasma in association with a papaya disease.

MALDI-TOF MS to identify the pineapple pathogen Fusarium guttiforme and its antagonist Trichoderma asperellum on decayed pineapple

Matrix-assisted laser desorption⁄ionisation time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify some Fusarium and Trichoderma species, but early detection of fungal diseases by this technique has not yet been fully addressed. In this study, MALDI-TOF MS was tested to identify F. guttiforme on pineapple side shoots in situ. The efficacy of filamentous fungi for controlling fungal diseases is well documented. However, there is uncertainty whether the biocontrol agent is out growing the pathogen sufficiently to be identified. In this paper, a multistep identification of a plant pathogen (F. guttiforme) and its antagonist (T. asperellum) using MALDI-TOF MS is demonstrated.

Postharvest rot and mummification of strawberry fruits caused by Neofusicoccum parvum and N. kwambonambiense in Brazil

In addition to the rots that are commonly found on strawberries, a new disease was found in 7% of stored fruits during a survey of strawberry diseases at the postharvest stage. Kochs postulates were satisfied, and the fungi were identified as Neofusicoccum kwambonambiense and N. parvum based on morphology and phylogenetic analysis of the internal transcribed spacers, β-tubulin, RNA polymerase subunit II and transcription elongation factor 1-α regions. This is the first report of Neofusicoccum kwambonambiense in Brazil and the first report of Neofusicoccum spp. causing mummification and postharvest rot of strawberry.

Two new Ceratobasidium species causing white thread blight on tropical plants in Brazil

White thread blight is one of the most common diseases affecting several tree species that grow in warm and humid regions. The typical symptoms of this disease include blighted leaves hanging by a white thread of fungal hyphae. Leaf samples exhibiting white thread blight symptoms were collected from neem (Azadirachta indica A. Juss) and Brazilian cherry pitanga (Eugenia uniflora L.) plants in Northeastern Brazil, and from Indian green-tea (Camellia sinensis (L.) O. Kuntze), coffee (Coffea arabica L.), and persimmon (Diospyros kaki L.) in agricultural areas neighboring the Atlantic forest in Southeastern Brazil. Fungal isolates were obtained indirectly from leaf fragments or directly by transferring mycelia and sclerotia to culture medium. Bright field and scanning electron microscopy images revealed the association of Rhizoctonia-like hyphae and basidiospores with the infected leaves. In pathogenicity tests, Rhizoctonia-like fungal isolates induced leaf necrosis on their hosts, and the pathogens were re-isolated from inoculated plants. Phylogenetic analyses based on sequences of the ITS rRNA region indicated the occurrence of Ceratobasidium lineages distinct from previously reported Ceratobasidium species. Our study leads to the description of two new species of Ceratobasidium: the fungal isolates from A. indica, C. sinensis, and E. uniflora were classified as Ceratobasidium niltonsouzanum sp. nov., and those obtained from C. arabica and D. kaki as Ceratobasidium chavesanum sp. nov.

Spread of Two Invasive Flies (Diptera: Drosophilidae) Infesting Commercial Fruits in Southeastern Brazil

Summary Two invasive fruit flies, Drosophila suzukii Matsumura and Zaprionus indianus Gupta (Diptera: Drosophilidae), recently have become established, and are expanding their range in the Neotropics. This research documents the range expansion of these species in southeastern Brazil, where they were found infesting cultivated blackberries and strawberries in the highlands of Espírito Santo, Brazil. Drosophila suzukii also was found associated with rotting Psidium cattleianum, and for the first time associated with papaya at sea level. Drosophila suzukii and Z. indianus may further affect establishment and production of important soft fruit crops and papaya in this region of Brazil. Management methods for fruit production in this Brazilian region need to be improved to avoid damage and further spread of D. suzukii.