LIBRO-CONGRESO-CITRUS

S15
and 41 kg, UTC trees produced 30 and 6 kg, in experiments 1 and 2, respectively. Fruit yield was intermediary
in both experiments for carbendazim (61 and 23 kg) and Cyp/Flu (53 and 13 kg). Therefore, Tri/Teb mixture
is a satisfactory, more efficient option for replacing carbendazim for control of PFD. Supported by FAPESP
(08⁄54599–2 and 08⁄54176–4).
S15P18
Survival of Colletotrichum acutatum in citrus leaves
Pereira W.V. 1 , Tanaka F.A.O. 1 , Rodrigues M.B.C. 2 , and Massola-Junior N.S. 1
1 University of São Paulo (USP), Plant Pathology and Nematology, Brazil; and 2 University of São Paulo (USP), Genetics, Brazil.
wvpereira@hotmail.com
Citrus Postbloom Fruit Drop (PFD) disease caused by Colletotrichum acutatum became recently an important
issue for citrus industry in Brazil. The determination of the source of inoculum and its survival period is
essential to understand the epidemiology and to develop strategies for the management of this disease. The
survival of C. acutatum on the surface of orange leaves was investigated. Leaves from ‘Pera’ sweet orange
saplings were inoculated with 105 conidia/mL and kept in a moist chamber for 48 h. For greenhouse and
field experiments, the saplings were inoculated with standard isolates. For growth chamber experiments
(21°C and 27°C), it was used a GFP gene-labeled isolate. Samples of inoculated leaf areas were taken and
evaluated monthly. This evaluation was made by the isolation of C. acutatum in a semi-selective medium and/
or visualization by fluorescence in a confocal microscope. Under controlled conditions, the pathogen survived
on the surface of the leaves for seven months at 21°C and for four months at 27°C. In the greenhouse, the
survival was three months and two months in the field. Recognition of the isolated cultures was made by PCR.
These data indicate that orange leaves can play an important role as source of inoculum for PFD.
S15P19
Pollen exudate stimulates conidial germination of Colletotrichum acutatum
Gasparoto M.C.G., Lourenço S.A., Marques J.P.R., Appezzato-da-Glória B., and Amorim L.
Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Fitopatologia e Nematologia, Brazil. mcggaspa@yahoo.com
Postbloom Fruit Drop, caused by Colletotrichum acutatum and C. gloeosporioides, is an important citrus
disease in the southwestern region of São Paulo State in Brazil. The high frequency of rain during the blooming
period causes explosive epidemics. Citrus flower extract, resulting from the contact of rainwater with petals,
stimulates the germination of appressoria and secondary conidia formation. The objective of this study was
to evaluate the conidial germination of C. acutatum in the presence of pollen exudate. Anthers were removed
from flowers of healthy citrus plants and transferred to 2 mL-sterile water. This mixture was agitated and the
suspension was adjusted to 105 pollen/mL. Conidial suspension was adjusted to 105 spores/mL. Three 35
µL-aliquots of conidial suspension plus three 35 µL-aliquots of pollen suspension were placed on polystyrene
Petri dishes, totaling 70 µL of a homogeneous suspension in each aliquot. The control was obtained with 70
µL-aliquot of spore suspension. Each dish was placed inside a gerbox containing a filter paper and 30 µL of
sterile water. The gerboxes were incubated in growth chambers at 24°C, without light, for 2, 4, 6, 8, 10, 12, 24
hours. Spore germination was calculated observing 100 conidia per aliquot. Twenty-four hours after in vitro
inoculation, conidial germination was 100% in the presence of pollen exudate and 8% in its absence.
S15P20
Fungal diseases of citrus in Panama
Aguilera-Cogley V. 1 , and Vicent A. 2
1Instituto de Investigaciones Agropecuarias de Panamá (IDIAP), Laboratorio de Protección Vegetal, Panamá; and 2Instituto Valenciano
de Investigaciones Agrarias (IVIA), Centro de Protección Vegetal y Biotecnología, Spain. avicent@ivia.es
The citrus-growing area in Panama has increased considerably in recent years. Disease problems are frequently
observed in the orchards, but in most cases their etiology is unknown, complicating the design of effective
266 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012