Identificação e prevalência de fungos associados à cultura da macadâmia
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2022-03-28
Autores
Silva, Rosicléia da
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Universidade Estadual Paulista (Unesp)
Resumo
A macadâmia é uma noz originária das florestas tropicais e subtropicais da Austrália, e vem ganhando destaque devido a sua importância no setor alimentício e de cosméticos. A produção mundial é liderada pela África do Sul e Austrália. No Brasil, o estado de São Paulo é o maior produtor. Dada a importância dessa cultura em expansão e à escassez de informações referentes a problemas fitossanitários no Brasil, o presente trabalho teve como objetivos identificar os microrganismos associados e os fitopatogênicos à cultura da macadâmia, bem como definir as suas épocas de ocorrência, temperatura ideal de crescimento e sensibilidade a fungicidas. Os órgãos da planta com sintomas de doenças e/ou sinais de colonização fúngica foram coletados mensalmente, por três anos consecutivos (2019, 2020 e 2021) em áreas de cultivo de macadâmia, predominantemente, em Dois Córregos, SP. Isolados representativos com patogenicidade confirmada foram identificados por caracterização morfológica e molecular. Ensaios do efeito da temperatura no crescimento micelial de Cladosporium sp., utilizando as temperaturas 20-30 °C, e dos isolados Lasiodiplodia sp. e Colletotrichum sp. com as temperaturas 23-30 °C foram realizados bem como a sensibilidade desses isolados a seis fungicidas distintos. As principais doenças, seus agentes causais e época de prevalência foram: cancro do caule, causado por Lasiodiplodia pseudotheobromae (novembro a abril); seca do rácemo causada por Cladosporium xanthochromaticum (março a agosto) e podridão do fruto causada por Colletotrichum siamense (abril de 2021). Os fungos C. xanthochromaticum e C. siamense apresentaram melhor desenvolvimento a 23 °C e L. pseudotheobromae a 30 °C. Quanto aos fungicidas, hidróxido de cobre inibiu a germinação de C. xanthochromaticum; epoxiconazol + piraclostrobina, clorotalonil, azoxistrobina + ciproconazol e fluxapiroxade + piraclostrobina inibiram tanto C. xanthochromaticum, L. pseudotheobromae e C. siamense; e procimidona inibiu somente o crescimento de L. pseudotheobromae. Os três fungos associados às doenças na macadâmia são relatados pela primeira vez no Brasil, sendo o primeiro relato de C. xanthochromaticum e C. siamense como agentes causais da seca do rácemo e podridão do fruto em macadâmia, respectivamente.
Macadamia is a nut tree native to the tropical and subtropical forests of Australia and has been rising in prominence due to its importance in the food and cosmetics markets. South Africa and Australia are the world´s greatest producers of this nut, and in Brazil, São Paulo is the state with the largest national production. Given the importance of this expanding culture and the scarcity of information regarding phytosanitary problems in Brazil, the present work had the objectives of identifying the microorganisms associated and phytopathogenic to the macadamia culture, as well as defining their seasons of occurrence, the ideal temperature of growth and sensitivity to fungicides. Plant organs with disease symptoms and/or signs of fungal colonization were collected monthly, for three consecutive years (2019, 2020, and 2021) in macadamia growing areas, predominantly, in Dois Córregos, SP. Representative isolates with confirmed pathogenicity were identified by morphological and molecular characterization. Tests of the effect of temperature on mycelial growth of Cladosporium sp. using temperatures 20-30 °C, and of Lasiodiplodia sp. and Colletotrichum sp. isolates using temperatures 23-30 °C were performed as well as the sensitivity of these isolates to six different fungicides. The main diseases, their causal agents, and season of prevalence were stem canker, caused by Lasiodiplodia pseudotheobromae (November to April), raceme blight caused by Cladosporium xanthochromaticum (March to August), and husk rot caused by Colletotrichum siamense (April 2021). The fungi C. xanthochromaticum and C. siamense showed better development at 23 °C and L. pseudotheobromae at 30 °C. As for the fungicides, copper hydroxide inhibited the germination of C. xanthochromaticum, epoxiconazole + pyraclostrobin, chlorothalonil, azoxystrobin + cyproconazole, and fluxapyroxad + pyraclostrobin inhibited both C. xanthochromaticum, L. pseudotheobromae, and C. siamense, and procymidone inhibited only the growth of L. pseudotheobromae. The three fungi associated with diseases in macadamia are reported for the first time in Brazil, with the first report of C. xanthochromaticum and C. siamense as causal agents of raceme blight and husk rot in macadamia, respectively.
Macadamia is a nut tree native to the tropical and subtropical forests of Australia and has been rising in prominence due to its importance in the food and cosmetics markets. South Africa and Australia are the world´s greatest producers of this nut, and in Brazil, São Paulo is the state with the largest national production. Given the importance of this expanding culture and the scarcity of information regarding phytosanitary problems in Brazil, the present work had the objectives of identifying the microorganisms associated and phytopathogenic to the macadamia culture, as well as defining their seasons of occurrence, the ideal temperature of growth and sensitivity to fungicides. Plant organs with disease symptoms and/or signs of fungal colonization were collected monthly, for three consecutive years (2019, 2020, and 2021) in macadamia growing areas, predominantly, in Dois Córregos, SP. Representative isolates with confirmed pathogenicity were identified by morphological and molecular characterization. Tests of the effect of temperature on mycelial growth of Cladosporium sp. using temperatures 20-30 °C, and of Lasiodiplodia sp. and Colletotrichum sp. isolates using temperatures 23-30 °C were performed as well as the sensitivity of these isolates to six different fungicides. The main diseases, their causal agents, and season of prevalence were stem canker, caused by Lasiodiplodia pseudotheobromae (November to April), raceme blight caused by Cladosporium xanthochromaticum (March to August), and husk rot caused by Colletotrichum siamense (April 2021). The fungi C. xanthochromaticum and C. siamense showed better development at 23 °C and L. pseudotheobromae at 30 °C. As for the fungicides, copper hydroxide inhibited the germination of C. xanthochromaticum, epoxiconazole + pyraclostrobin, chlorothalonil, azoxystrobin + cyproconazole, and fluxapyroxad + pyraclostrobin inhibited both C. xanthochromaticum, L. pseudotheobromae, and C. siamense, and procymidone inhibited only the growth of L. pseudotheobromae. The three fungi associated with diseases in macadamia are reported for the first time in Brazil, with the first report of C. xanthochromaticum and C. siamense as causal agents of raceme blight and husk rot in macadamia, respectively.
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Macadamia integrifolia, Lasiodiplodia pseudotheobromae, Cladosporium xanthochromaticum, Colletotrichum siamense, epidemiologia, epidemiology