LIBRO-CONGRESO-CITRUS

S09
S09P30
Selection and in vitro evaluation of yeasts for control of Geotrichum candidum
Cunha T. 1 , Tosin E.S. 2 , and Kupper K.C. 3
1 Universidade Estadual Paulista ‘Júlio Mesquita Filho’ - Campus de Jaboticabal (UNESP), Microbiologia Agropecuária, Brazil;
2 Universidade Federal de São Carlos - Campus Araras (UFSCar), Ciências Biológicas, Brazil; and 3 Centro APTA Citros Sylvio Moreira
(IAC), Fitopatologia e Controle Biológico, Brazil. taticunha1989@hotmail.com
This paper aimed to test different yeast isolates obtained from soils, leaves, fruits and flowers of citrus from
different places in the State of São Paulo/Brazil for the antagonism to Geotrichum candidum, the causal agent
of Sour Rot of citrus. The decimal dilution technique, plating in YPD, YM and WLN medium, was used for the
isolation of potential antagonists. The colonies obtained were incubated at 25° C for 7 days in BOD chamber and
the isolated showing a distinctive morphology were purified in YEPD medium. These isolates were evaluated
for the antagonism by means of dual cultures in Petri dishes. The experiment was arranged in a completely
randomized design, with six replicates and the evaluation was performed by measuring the average diameter
of colony growth. The effect of yeast strains on the spore germination of G. candidum was assessed using the
technique of water-agar on glass slides, evaluating the 15 isolates with higher inhibitory effect in vitro. A total of
87 yeast isolates were obtained, and the best results were obtained with the yeast isolates ACBL-77, ACBL-23,
and ACBL-52, with a inhibitory effect ranging from 28% to 35%. The germination test showed that, except ACBL-
21, all isolates significantly inhibited the germination of G. candidum spores. The isolates ACBL-68 and ACBL-23
showed the highest inhibitory rates, with values of 87.7% and 83.4%, respectively.
S09P31
In vitro and in vivo evaluation of yeast isolates for biocontrol of Penicillium digitatum, causal
agent of Green Mold
Kupper K.C. 1 , Cunha T. 2 , and Tosin E.S. 3
1 Centro APTA Citros Sylvio Moreira (IAC), Fitopatologia e Controle Biológico, Brazil; 2 Universidade Estadual Paulista Júlio Mesquita
Filho - Campus de Jaboticabal (UNESP), Microbiologia Agropecuária, Brazil; and 3 Universidade Federal de São Carlos - Campus de
Araras (UFSCar), Ciências Biolólicas, Brasil. katia@centrodecitricultura.br
This work aimed to test different yeast isolates obtained from soils, leaves, fruits and flowers of citrus from
different places in the State of São Paulo/Brazil for in vitro and in vivo antagonism to Penicillium digitatum, the
causal agent of Green Mold. The in vitro evaluation was performed by means of dual cultures in Petri dishes.
The experiment was arranged in a completely randomized design, with six replicates and the evaluation
was performed by measuring the average diameter of colony growth. ‘Valencia’ sweet orange fruit (Citrus
sinensis) were washed and surface disinfected with a 0.7% sodium hypochlorite solution Fruit were injured in
two equidistant points with a 3 mm depth needle and inoculated with a conidial suspension of P. digitatum
(10 5 spores/mL) 24 hours before and after the treatments. Treatments were applied by dipping the fruits into
the antagonist suspensions (10 7 cfu/mL) for 2 minutes, or a fungicide solution of imazalil (0.2%). Inoculated
non-treated fruit were considered as control. All fruits were maintained at 20ºC and 99% RU for 7 days. A
completely randomized design with three replicates of 20 fruits was used. Control efficacy was evaluated
based on the percentage of diseased fruits. The best results in vitro were obtained with the isolates ACBL-07,
ACBL-14, ACBL-58 and ACBL-67, but they were ineffective in the assays in vivo.
S09P32
Optimal concentration of inoculum, types of injuries and control of Penicillium digitatum in
orange fruits
González-Fierro P. 1 , Nieto-Ángel D. 1 , Téliz-Ortiz D. 1 , Lara-Viveros F.M. 1 , and Orozco-Santos M. 2
1 Colegio de Postgraduados (CP), Instituto de Fitosanidad, México; and 2 Instituto Nacional de Investigaciones Forestales, Agrícolas y
Pecuarias (INIFAP), Campo Experimental Tecomán, México. orozco.mario@inifap.gob.mx
Green Mold, caused by Penicillium digitatum, is the most important postharvest disease of citrus in Mexico.
The objectives of this study were: 1) to evaluate the effect of nine different spore concentrations of the fungus
in orange fruits, 2) to determine the effect of three types of injuries to allow the disease after inoculation, and
150 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012