Dispersal of Colletotrichum acutatum and C. gloeosporioides, causal agents of postbloom fruit drop: would be insects the responsible agents for pathogen spread over long distances?

• Grant number: 11/20472-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2012
• End date: November 30, 2013
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Lilian Amorim
• Grantee: Maria Candida de Godoy Gasparoto
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 08/54176-4 - Molecular epidemiology and management of postbloom fruit drop of citrus in new planting areas in São Paulo State, AP.TEM

Abstract

Postbloom fruit drop, caused by Colletotrichum acutatum and C. gloeosporioides, became an important phytosanitary problem in São Paulo State since citrus crop migrated from North and Central regions to new areas in the Southwest (Neves et al., 2007). The high frequency of rain in the new areas, which is a favorable condition to flower infection during the flowering period, has resulted in the recent importance of the disease in São Paulo State. In this context, the thematic project "Molecular epidemiology and management of postbloom fruit drop of citrus in new planting areas in São Paulo State" (FAPESP process 2008/54176-4), to which this work will be related, has been produced relevant results for this pathosystem. Results from experiments carried out in orchards located in the Southwest region of São Paulo State show a random spatial pattern of the disease in the field when the conditions are favorable (Silva Jr., 2011). Besides, the epidemics have high disease progress rates, similar to those reported for late blight in potato, one of the most destructive diseases already reported (Madden et al., 2007; Vanderplank, 1963). This unexpected behavior of the disease in the field gives evidence that the pathogen has additional mechanisms of dispersal, since only rain splash could not explain so fast and severe epidemics. In this context, it was formulated the hypothesis that the pathogen is spread by bees (Apis mellifera), since they are often found in citrus orchards during the flowering period (Malerbo-Souza et al., 2003; Gamito & Malerbo-Souza, 2006) and they are able to carry the pathogen on their body or even infecting pollen grains (Marques & Appezzato-da-Glória, unpublished data) which are transported from the anther of an infected plant to a healthy plant, and in all of these cases, they are favoring the epidemics. Thus, the objectives of this study are: (i) to characterize the role of pollinating insects (bees) in the spread of C. acutatum and C. gloeosporioides among citrus plants in controlled environment, (ii) to characterize the role of infected pollen grains carried by insects in the spread of C. acutatum and C. gloeosporioides among citrus plants in controlled environment and (iii) to characterize the role of pollinating insects (bees) in the spread of C. acutatum and C. gloeosporioides in a citrus orchard.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GASPAROTO, M. C. G.; LOURENCO, S. A.; TANAKA, F. A. O.; SPOSITO, M. B.; MARCHINI, L. C.; SILVA JUNIOR, G. J.; AMORIM, L.. Honeybees can spread Colletotrichum acutatum and C-gloeosporioides among citrus plants. PLANT PATHOLOGY, v. 66, n. 5, p. 777-782, JUN 2017. (11/20472-9, 08/54176-4)