LIBRO-CONGRESO-CITRUS

3) to evaluate different treatments for disease control. Disease was observed in 100% of the inoculated fruits
when the inoculum concentration was equal or higher than 6x10 5 spores/mL. Symptoms did not appear with
concentrations of 1x10 4 and 3x10 4 spores/mL. When injuries were superficial (bruises and deformation) and
did not penetrate into the albedo, the infection did not occur. Wounds caused by punctures and cuts induced
symptoms after the inoculation. All treatments with Trichoderma viride and T. harzianum, as well as the
extract of Melaleuca aternifolia, failed to reduce disease incidence and severity in fruits. The best treatments
to control Green Mold were the fungicides pyrimethanil and thiabendazole.
S09P33
In vitro comparison of the effectiveness of disinfectants and a fungicide on the viability of spores
of Geotrichum citri-aurantii.
Diaz L.D. 1 , del Campo R.d.C. 2 , Peyrou M.P. 2 , and Mara H.M. 2
1Dirección General de Sevicios Agrícolas (MGAP), Montevideo, Uruguay; and 2Instituto de Investigaciones Biológicas ‘Clemente
Estable’ (IIBCE), Montevideo, Uruguay. raqueldc60@gmail.com
Sour Rot (Geotrichum citri-aurantii) is an important postharvest disease of citrus in Uruguay. The disease has
been managed so far by using sodium orthophenylphenate (SOPP) and 9-Aza-1,17-diguanidinoetadecane
(guazatine). Both fungicides leave residue levels in fruit that are generally not acceptable for export. Therefore,
the development of alternative control treatments, such as disinfection, is required. The objective of this
work was to compare the effect of various disinfectants and one fungicide on the viability of Geotrichum
spores in vitro. The products evaluated were: 200 ppm sodium hypochlorite, 100 ppm stabilized chlorine
dioxide (Tecsaclor®), pH 6 and 6.5; 5000 ppm chloramine-T (Bac-T®); 1600 ppm didecyl dimethyl ammonium
chloride/ alkyl amido propyl chloride dimethyl benzyl ammonium chloride (Tefor®); 120 ppm dimethil didecyl
ammonium chloride (Sporekill®). The efficacy of 20000 ppm SOPP was also evaluated. For all treatments, a
suspension containing 106 spores/mL was prepared and exposed directly to each product solution for 1, 2
or 4 min. The results obtained were compared with those of untreated control fruit. The highest efficiency
was obtained for ammonium and chlorine dioxide (pH 6) compounds, which reduced 100% spore viability
for the three exposure times evaluated. Sodium hypochlorite during 2 and 4 min killed 97% and 100% of the
spores, respectively. Tecsaclor (pH 6.5) reduced 99.8% and 100% of the spores after 2 and 4 min of exposure,
respectively. SOPP did not produce a satisfactory effect.
S09P34
Alternative treatments for postharvest decay control on ‘Ponkan’ tangerines
Montero C.R.S. 1 , dos Santos L.C. 2 , Andreazza C.S. 2 , Schwarz L.L. 2 , and Bender R.J. 2
1 (Fepagro), Research Station Serra do Nordeste, Caxias do Sul; and 2 (UFRGS), Horticultural Sciences, Agronomy, Brazil. rjbe@ufrgs.br
Penicillium spp. are the most frequent pathogens associated with postharvest decay in citrus fruit. Pre- and
postharvest chemical sprays are the most widespread methods to reduce incidence, though, in the scientific
literature there is plenty of evidence on promising alternative postharvest treatments. Therefore, in the
present work the objective was to evaluate the effects of alternative treatments on the control of Green
and Blue Mold and on the postharvest quality of ‘Ponkan’ tangerines. During two seasons, fruit harvested in
commercial orchards were treated with different combinations of sodium bicarbonate, potassium sorbate,
and heat treatments, in single or combined applications. Two control treatments, chloride dioxide and imazalil
were also included. The tangerines were evaluated after 15 or 30 days of cold storage at 5°C plus 5 more
days at room temperature for internal quality and decay incidence. Quality traits were not affected by any
of the treatments. Sodium bicarbonate at a concentration of 2% (w/v) and potassium sorbate at 0,5% (w/v)
significantly reduced decay on ‘Ponkan’ fruit after 30 days of storage. However, peel brightness was negatively
affected by an immersion treatment of 30 sec at 58°C with both salts at concentrations higher than 3% and
1%, respectively. Further research on salt concentration and temperature combinations should be conducted
to conclude about the feasibility of alternative postharvest treatments for citrus fruit.
XII INTERNATIONAL CITRUS CONGRESS 2012 - 151
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