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Joseph L Smilanick - One of the best experts on this subject based on the ideXlab platform.
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Conventional and reduced-risk fungicides to control postharvest Diplodia and Phomopsis stem-end rot on Lemons
Scientia Horticulturae, 2017Co-Authors: Luciana Cerioni, Joseph L Smilanick, Paula B. Bennasar, Daniela Lazarte, Milena Sepulveda, Jaqueline Ramallo, Viviana A. RapisardaAbstract:Abstract Stem-end-rot (SER), caused by Lasiodiplodia theobromae or Diaporthe citri, is an important postharvest disease in humid and warm citrus growing areas, such as the Northwestern region of Argentina. The commercial control of SER has been accomplished by applications of the systemic fungicide carbendazim (CARB). However, alternative chemicals for this fungicide are needed due to increasing restrictive regulations in overseas markets. The aim of this work was to evaluate the effectiveness of conventional and reduced-risk postharvest fungicides to control SER. In vitro tests show that L. theobromae was more resistant to fungicides than D. citri. In trials using artificially inoculated Lemons, SER caused by D. citri (Phomopsis SER) was controlled by the fungicides evaluated. The conventional fungicides imazalil and thiabendazole (TBZ) were the most effective chemicals to control SER caused by L. theobromae (Diplodia SER), while other fungicides, as fludioxanil, azoxystrobin, pyrimetanil and propiconazole, were not effective. The best control of Diplodia SER was obtained by immersion for 60 s in 2000 mg/L of TBZ at pH 5 and 20 °C. In this condition, TBZ-residue loading on Lemons was 3.0 mg-L−1, which did not exceed the allowed maximum residue levels. TBZ applied in lemon commercial treatments is the best option to reduce SER caused by both pathogens. At this time, this is the unique suitable alternative to replace CARB treatment in Argentinean packinghouses.
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control of green mold and sour rot of stored lemon by biofumigation with muscodor albus
Biological Control, 2005Co-Authors: Julien Mercier, Joseph L SmilanickAbstract:Control of postharvest lemon diseases by biofumigation with the volatile-producing fungus Muscodor albus was investigated. In vitro exposure to M. albus volatile compounds for 3 days killed Penicillium digitatum and Geotrichum citri-aurantii, causes of green mold and sour rot of Lemons, respectively. Lemons were wound-inoculated with P. digitatum and placed in closed 11-L plastic boxes with rye grain cultures of M. albus at ambient temperature. There was no contact between the fungus and the fruit. Biofumigation for 24–72 h controlled green mold signiWcantly, even when treatment began 24 h after inoculation. EVectiveness was related to the amount of M. albus present. In tests conducted inside a 11.7-m 3 degreening room with 5 ppm ethylene at 20 °C, green mold incidence on Lemons was reduced on average from 89.8 to 26.2% after exposure to M. albus for 48 h. Ethylene accelerates color development in harvested citrus fruit. M. albus had no eVect on color development. Biofumigation in small boxes immediately after inoculation controlled sour rot, but was ineVective if applied 24 h later. G. citri-aurantii may be less sensitive to the volatile compounds than P. digitatum or escapes exposure within the fruit rind. Biofumigation with M. albus could control decay eVectively in storage rooms or shipping packages.
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impact of a brief postharvest hot water drench treatment on decay fruit appearance and microbe populations of california Lemons and oranges
Horttechnology, 2003Co-Authors: Joseph L Smilanick, David Sorenson, Monir Mansour, Jonah Aieyabei, Pilar PlazaAbstract:A brief (15 or 30 seconds) high-volume, low-pressure, hot-water drench at 68, 120, 130, 140, or 145 °F (20.0, 48.9, 54.4, 60.0, or 62.8 °C) was applied over rotating brushes to ‘Eureka’ Lemons (Citrus limon) and ‘Valencia’ oranges (Citrus sinensis). The impact of this treatment on populations of surface microbes, injury to the fruit, the incidence of green mold (Penicillium digitatum)or sour rot (Geotrichum citri-aurantii), when inoculated into wounds one day prior to treatment, and temperatures required to kill the spores of these fungi and P. italicum suspended in hot water were determined. Fruit microbial populations were determined immediately after treatment. Decay and injuries were assessed after storage for 3 weeks at 55 °F (12.8 °C). The efficacy of the hot water treatments was compared to immersion of fruit in 3% wt/vol sodium carbonate at 95 °F (35.0 °C) for 30 seconds, a common commercial practice in California. Initial yeast and mold populations, initially log10 6.0 per fruit, were reduced to log10 3.3 on Lemons and log10 4.2 on oranges by a 15-second treatment at 145 °F. Green mold control improved with increasing temperature and treatment duration. Green mold incidence was reduced from 97.9% and 98.0% on untreated Lemons and oranges, respectively, to 14.5% and 9.4% by 30 seconds treatment with 145 °F water. However, immersion of Lemons or oranges in 3% wt/vol sodium carbonate was superior and reduced green mold to 8.0% and 8.9%, respectively. Sour rot incidence on Lemons averaged 84.3% after all water treatments, and was not significantly reduced, although arthrospores of G. citriaurantii died at lower water temperatures than spores of P. digitatum and P. italicum in in vitro tests. Sodium carbonate treatment for 30 seconds at 95 °F reduced sour rot to 36.7%. None of the treatments caused visible injuries to the fruit.
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enhancement of the performance of candida saitoana by the addition of glycolchitosan for the control of postharvest decay of apple and citrus fruit
Postharvest Biology and Technology, 2000Co-Authors: Joseph L Smilanick, Ahmed Elghaouth, Charles L WilsoAbstract:At a concentration of 0.025% (w/v) chitosan-chloride inhibited spore germination of Botrytis cinerea, Penicillium expansum, and Candida saitoana. In contrast, at 0.5% (w/v) glycolchitosan inhibited spore germination of B. cinerea and P. expansum, but not the growth of C. saitoana in vitro or in apple wounds. The combination of C. saitoana with 0.2% glycolchitosan was more effective in controlling gray and blue mold of apple caused by B. cinerea and P. expansum, respectively, and green mold of oranges and Lemons caused by P. digitatum than C. saitoana or 0.2% glycolchitosan alone. The level of control was similar to that obtained with the fungicide imazalil on oranges and Lemons. C. saitoana in combination with 0.2% glycolchitosan reduced green mold incidence equally on light green and yellow Lemons, while C. saitoana was more effective on light green Lemons than on yellow Lemons. When applied as a pretreatment, sodium carbonate enhanced the efficacy of all treatments tested against green mold with the greatest effect on light green Lemons. Of the treatments tested, pretreatment with sodium carbonate followed by the combination of C. saitoana with 0.2% glycolchitosan was the most effective in controlling green mold of both light green and yellow Lemons.
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evaluation of heated solutions of sulfur dioxide ethanol and hydrogen peroxide to control postharvest green mold of Lemons
Plant Disease, 1995Co-Authors: Joseph L Smilanick, D A Margosan, Delmer J HensonAbstract:Lemon fruit were inoculated with spores of Penicillium digitatum and immersed in solutions of ethanol. sulfur dioxide, or hydrogen peroxide to control postharvest green mold. Green mold incidence and fruit injury were assessed after treatments employing various combinations of concentration, duration of treatment, temperature, and post-treatment rinses. Heating of the solutions was needed to attain acceptable efficacy. Sulfur dioxide and ethanol controlled green mold without injury to fruit, whereas hydrogen peroxide did not effectively control green mold and caused unacceptable injury to fruit. Treatments selected for extensive evaluation were immersion in 10% ethanol at 45 degrees C for 150 s without rinsing, or in 2% sulfur dioxide at 45 degrees C for 150 s followed by two fresh water rinses. These treatments were compared with two existing decay control methods: immersion in 3% sodium carbonate at 45 degrees C for 150 s followed by two fresh water rinses, or in 1,000 microgram/ml imazalil at 25 degrees C for 60 s. Lemons were inoculated at 20 degrees C then incubated for 12, 24, 48, or 60 h before treatments were applied. Efficacy of sulfur dioxide and ethanol treatments was comparable to that of sodium carbonate and imazalil. Sulfur dioxide and ethanol did not injure the fruit and their residues were low. The sulfur dioxide content of Lemons immediately after treatment was less than 1 microgram/ml. The ethanol content of Lemons analyzed immediately after ethanol treatment was 58.6 (plus or minus 9.6) microgram/ml and 24.4 (plus or minus 11.7) microgram/ml after storage for 7 days at 20 C. The ethanol content of untreated fruit was 3.3 microgram/ml.
Jérémie Santini - One of the best experts on this subject based on the ideXlab platform.
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Tetraploid citrus seedlings subjected to long-term nutrient deficiency are less affected at the ultrastructural, physiological and biochemical levels than diploid ones
Plant Physiology and Biochemistry, 2019Co-Authors: Julie Oustric, François Luro, Yann Quilichini, Raphaël Morillon, Stéphane Herbette, Jean Giannettini, Liliane Berti, Jérémie SantiniAbstract:Nutrient deficiency has economic and ecological repercussions for citrus fruit crops worldwide. Citrus crops rely on fertilization to maintain good fruit output and quality, whereas new crop management policy aims to reduce fertilizers input. New rootstocks are needed to meet to this constraint, and the use of new tetraploid rootstocks better adapted to lower nutrient intake could offer a promising way forward. Here we compared physiological, biochemical and anatomic traits of leaves in diploid (2x) and doubled-diploid (4x) Citrumelo 4475 (Citrus paradisi L. Macf. × Poncirus trifoliata L. Raf.) and Volkamer lemon (Citrus limonia Osb.) seedlings over 7 months of nutrient deficiency. Photosynthetic parameters (Pnet, Gs and Fv/Fm) decreased, but to a lesser extent in 4x genotypes than 2x. Degradation of the ultrastructural organelles (chloroplasts and mitochondria) and compound cells (thylakoids and starches) was also lower in 4x genotypes, suggesting that tetraploidy may enhance tolerance to nutrient deficiency. However, leaf surface (stomata, stomatal density and epithelial cells) showed no nutrient deficiency-induced change. In 4x Citrumelo 4475, the higher tolerance to nutrient deficiency was associated with a lower MDA and H2O2 accumulation than in the 2x, suggesting a more efficient antioxidant system in the 4x genotype. However, few differences in antioxidant system and oxidative status were observed between 2x and 4x Volkamer Lemons.
François Luro - One of the best experts on this subject based on the ideXlab platform.
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Tetraploid citrus seedlings subjected to long-term nutrient deficiency are less affected at the ultrastructural, physiological and biochemical levels than diploid ones
Plant Physiology and Biochemistry, 2019Co-Authors: Julie Oustric, François Luro, Yann Quilichini, Raphaël Morillon, Stéphane Herbette, Jean Giannettini, Liliane Berti, Jérémie SantiniAbstract:Nutrient deficiency has economic and ecological repercussions for citrus fruit crops worldwide. Citrus crops rely on fertilization to maintain good fruit output and quality, whereas new crop management policy aims to reduce fertilizers input. New rootstocks are needed to meet to this constraint, and the use of new tetraploid rootstocks better adapted to lower nutrient intake could offer a promising way forward. Here we compared physiological, biochemical and anatomic traits of leaves in diploid (2x) and doubled-diploid (4x) Citrumelo 4475 (Citrus paradisi L. Macf. × Poncirus trifoliata L. Raf.) and Volkamer lemon (Citrus limonia Osb.) seedlings over 7 months of nutrient deficiency. Photosynthetic parameters (Pnet, Gs and Fv/Fm) decreased, but to a lesser extent in 4x genotypes than 2x. Degradation of the ultrastructural organelles (chloroplasts and mitochondria) and compound cells (thylakoids and starches) was also lower in 4x genotypes, suggesting that tetraploidy may enhance tolerance to nutrient deficiency. However, leaf surface (stomata, stomatal density and epithelial cells) showed no nutrient deficiency-induced change. In 4x Citrumelo 4475, the higher tolerance to nutrient deficiency was associated with a lower MDA and H2O2 accumulation than in the 2x, suggesting a more efficient antioxidant system in the 4x genotype. However, few differences in antioxidant system and oxidative status were observed between 2x and 4x Volkamer Lemons.
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phylogenetic origin of limes and Lemons revealed by cytoplasmic and nuclear markers
Annals of Botany, 2016Co-Authors: Franck Curk, François Luro, Frederique Ollitrault, Andres Garcialor, Luis Navarro, Patrick OllitraultAbstract:Background and Aims The origin of limes and Lemons has been a source of conflicting taxonomic opinions. Biochemical studies, numerical taxonomy and recent molecular studies suggested that cultivated Citrus species result from interspecific hybridization between four basic taxa (C. reticulata, C. maxima, C. medica and C. micrantha). However, the origin of most Lemons and limes remains controversial or unknown. The aim of this study was to perform extended analyses of the diversity, genetic structure and origin of limes and Lemons. Methods The study was based on 133 Citrus accessions. It combined maternal phylogeny studies based on mitochondrial and chloroplastic markers, and nuclear structure analysis based on the evaluation of ploidy level and the use of 123 markers, including 73 basic taxa diagnostic single nucleotide polymorphism (SNP) and indel markers. Key Results The lime and lemon horticultural group appears to be highly polymorphic, with diploid, triploid and tetraploid varieties, and to result from many independent reticulation events which defined the sub-groups. Maternal phylogeny involves four cytoplasmic types out of the six encountered in the Citrus genus. All lime and lemon accessions were highly heterozygous, with interspecific admixture of two, three and even the four ancestral taxa genomes. Molecular polymorphism between varieties of the same sub-group was very low. Conclusions Citrus medica contributed to all limes and Lemons and was the direct male parent for the main sub-groups in combination with C. micrantha or close papeda species (for C. aurata, C. excelsa, C. macrophylla and C. aurantifolia – 'Mexican' lime types of Tanaka's taxa), C. reticulata (for C. limonia, C. karna and C. jambhiri varieties of Tanaka's taxa, including popular citrus rootstocks such as 'Rangpur' lime, 'Volkamer' and 'Rough' Lemons), C. aurantium (for C. limetta and C. limon – yellow lemon types – varieties of Tanaka's taxa) or the C. maxima × C. reticulata hybrid (for C. limettioides – 'Palestine sweet' lime types – and C. meyeri). Among triploid limes, C. latifolia accessions ('Tahiti' and 'Persian' lime types) result from the fertilization of a haploid ovule of C. limon by a diploid gamete of C. aurantifolia, while C. aurantifolia triploid accessions ('Tanepao' lime types and 'Madagascar' lemon) probably result from an interspecific backcross (a diploid ovule of C. aurantifolia fertilized by C. medica). As limes and Lemons were vegetatively propagated (apomixis, horticultural practices) the intra-sub-group phenotypic diversity results from asexual variations. (Resume d'auteur)
Julie Oustric - One of the best experts on this subject based on the ideXlab platform.
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Tetraploid citrus seedlings subjected to long-term nutrient deficiency are less affected at the ultrastructural, physiological and biochemical levels than diploid ones
Plant Physiology and Biochemistry, 2019Co-Authors: Julie Oustric, François Luro, Yann Quilichini, Raphaël Morillon, Stéphane Herbette, Jean Giannettini, Liliane Berti, Jérémie SantiniAbstract:Nutrient deficiency has economic and ecological repercussions for citrus fruit crops worldwide. Citrus crops rely on fertilization to maintain good fruit output and quality, whereas new crop management policy aims to reduce fertilizers input. New rootstocks are needed to meet to this constraint, and the use of new tetraploid rootstocks better adapted to lower nutrient intake could offer a promising way forward. Here we compared physiological, biochemical and anatomic traits of leaves in diploid (2x) and doubled-diploid (4x) Citrumelo 4475 (Citrus paradisi L. Macf. × Poncirus trifoliata L. Raf.) and Volkamer lemon (Citrus limonia Osb.) seedlings over 7 months of nutrient deficiency. Photosynthetic parameters (Pnet, Gs and Fv/Fm) decreased, but to a lesser extent in 4x genotypes than 2x. Degradation of the ultrastructural organelles (chloroplasts and mitochondria) and compound cells (thylakoids and starches) was also lower in 4x genotypes, suggesting that tetraploidy may enhance tolerance to nutrient deficiency. However, leaf surface (stomata, stomatal density and epithelial cells) showed no nutrient deficiency-induced change. In 4x Citrumelo 4475, the higher tolerance to nutrient deficiency was associated with a lower MDA and H2O2 accumulation than in the 2x, suggesting a more efficient antioxidant system in the 4x genotype. However, few differences in antioxidant system and oxidative status were observed between 2x and 4x Volkamer Lemons.
Delmer J Henson - One of the best experts on this subject based on the ideXlab platform.
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evaluation of heated solutions of sulfur dioxide ethanol and hydrogen peroxide to control postharvest green mold of Lemons
Plant Disease, 1995Co-Authors: Joseph L Smilanick, D A Margosan, Delmer J HensonAbstract:Lemon fruit were inoculated with spores of Penicillium digitatum and immersed in solutions of ethanol. sulfur dioxide, or hydrogen peroxide to control postharvest green mold. Green mold incidence and fruit injury were assessed after treatments employing various combinations of concentration, duration of treatment, temperature, and post-treatment rinses. Heating of the solutions was needed to attain acceptable efficacy. Sulfur dioxide and ethanol controlled green mold without injury to fruit, whereas hydrogen peroxide did not effectively control green mold and caused unacceptable injury to fruit. Treatments selected for extensive evaluation were immersion in 10% ethanol at 45 degrees C for 150 s without rinsing, or in 2% sulfur dioxide at 45 degrees C for 150 s followed by two fresh water rinses. These treatments were compared with two existing decay control methods: immersion in 3% sodium carbonate at 45 degrees C for 150 s followed by two fresh water rinses, or in 1,000 microgram/ml imazalil at 25 degrees C for 60 s. Lemons were inoculated at 20 degrees C then incubated for 12, 24, 48, or 60 h before treatments were applied. Efficacy of sulfur dioxide and ethanol treatments was comparable to that of sodium carbonate and imazalil. Sulfur dioxide and ethanol did not injure the fruit and their residues were low. The sulfur dioxide content of Lemons immediately after treatment was less than 1 microgram/ml. The ethanol content of Lemons analyzed immediately after ethanol treatment was 58.6 (plus or minus 9.6) microgram/ml and 24.4 (plus or minus 11.7) microgram/ml after storage for 7 days at 20 C. The ethanol content of untreated fruit was 3.3 microgram/ml.
