Ramon Jaime | University of California, Davis (original) (raw)

Papers by Ramon Jaime

Research paper thumbnail of Module storage time, leaf grade and seed moisture influence fiber quality and aflatoxin contamination of cotton in South Texas

Journal of cotton science, Mar 7, 2013

Research paper thumbnail of Etiology and management of aflatoxin contamination

Mycotoxins: detection methods, management, public health and agricultural trade, 2008

Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and reduce health ... more Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and reduce health and economic welfare in several portions of Africa. Crops are contaminated in two phases: (i) Aspergillus species infect crops during development; and (ii) after maturation contamination builds during exposure to warm humid conditions. Identification of the exact fungi causing contamination can provide clues to management strategies. Crops usually are infected by complex mixtures of aflatoxin-producing and closely related fungi. Among these are atoxigenic strains that produce no aflatoxins. In the United States atoxigenic strains are used to reduce contamination. Such technologies also may have value in Africa.

Research paper thumbnail of Aspergillus flavusdiversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

Annals of the New York Academy of Sciences, 2012

Research paper thumbnail of PLANT PATHOLOGY AND NEMATOLOGY Module Storage Time, Leaf Grade and Seed Moisture Influence Fiber Quality and Aflatoxin Contamination of Cotton in South Texas

Cotton is the most important natural fiber used to produce apparel, home furnishings, and industr... more Cotton is the most important natural fiber used to produce apparel, home furnishings, and industrial products. Cotton fiber quality influences both manufacturing efficiency and quality of the finished products. The color, length, strength, and purity of cotton fibers all contribute to fiber quality. Cottonseed is used as food (primarily oil) and is a preferred feed for dairy cows, with dairies paying a premium for cottonseed free of aflatoxin. Modules (14,200) of seed cotton grown in South Texas from 2002 through 2008 were analyzed for fiber quality and seed aflatoxin content. Harvest date, gin date, leaf grade, and seed moisture were related with fiber quality and seed aflatoxin content. Module storage time from harvest to ginning also influenced aflatoxin contamination and fiber quality. Standard fiber quality measurements, including lint color and spot, were related with aflatoxin content and, thus, might be useful predictors of seed aflatoxin contamination. Results suggest reduc...

Research paper thumbnail of Quantification of the Aflatoxin Biocontrol Strain Aspergillus flavus AF36 in Soil and in Nuts and Leaves of Pistachio by Real-Time PCR

Plant Disease

The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing ... more The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels, conditioning their sale. Strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCAs) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCAs are labor intensive and time consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on the sequence of aflC, a gene essential for aflatoxi...

Research paper thumbnail of Comparative effects of hermetic and traditional storage devices on maize grain: Mycotoxin development, insect infestation and grain quality

Journal of Stored Products Research

Research paper thumbnail of Resistance of maize land races from Mexico to aflatoxin contamination

Research paper thumbnail of Present Status and Perspective on the Future Use of Aflatoxin Biocontrol Products

Agronomy

Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and s... more Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and subtropical regions. The contamination is caused mainly by Aspergillus flavus and A. parasiticus. Aflatoxin contamination negatively affects health and trade sectors and causes economic losses to agricultural industries. Many pre- and post-harvest technologies can limit aflatoxin contamination but may not always reduce aflatoxin concentrations below tolerance thresholds. However, the use of atoxigenic (non-toxin producing) isolates of A. flavus to competitively displace aflatoxin producers is a practical strategy that effectively limits aflatoxin contamination in crops from field to plate. Biocontrol products formulated with atoxigenic isolates as active ingredients have been registered for use in the US, several African nations, and one such product is in final stages of registration in Italy. Many other nations are seeking to develop biocontrol products to protect their crops. In this r...

Research paper thumbnail of Applications of Geographic Information Systems and Geostatistics in Plant Disease Epidemiology and Management

Research paper thumbnail of Aspergillus flavus communities associated with commercial cottonseed in south Texas

Aspergillus flavus is the main causal agent of aflatoxin contamination of cottonseed. A. flavus c... more Aspergillus flavus is the main causal agent of aflatoxin contamination of cottonseed. A. flavus can be divided into two strains, S and L, based on physiological, morphological, and genetic criteria. Strain S isolates produce greater quantities of aflatoxins than L strain isolates in cottonseed. Aflatoxin contamination of cottonseed can be severe in South Texas. The structure of A. flavus communities associated with South Texas cottonseed was determined by analyzing 186 truckloads of commercial cottonseed sampled at the Valley Co-op Oil Mill in Harlingen, Texas from 1999 through 2001. The quantity of A. flavus (CFU) and the percent of A. flavus composed of the S strain were both correlated with aflatoxin contamination of South Texas cottonseed. CFU differed between both regions and seasons, while percent S only differed between regions. The Rio Grande Valley had significantly lower CFU and S strain than the Coastal Bend and Upper Coast regions. Cottonseed produced in 1999 had signifi...

Research paper thumbnail of Aflatoxin-producing fungi in maize field soils from sea level to over 2000 masl: A three year study in Sonora, Mexico

Research paper thumbnail of Crop rotation and soil temperature influence the community structure of Aspergillus flavus in soil

Soil Biology and Biochemistry, 2010

Research paper thumbnail of Aspergillus flavus in Soils and Corncobs in South Texas: Implications for Management of Aflatoxins in Corn-Cotton Rotations

Research paper thumbnail of Aflatoxin Contamination of Commercial Cottonseed in South Texas

Research paper thumbnail of Temporal and Spatial Patterns of Genetic Structure of Phytophthora infestans from Tomato and Potato in the Del Fuerte Valley

Research paper thumbnail of Spatial Analysis of Phytophthora infestans Genotypes and Late Blight Severity on Tomato and Potato in the Del Fuerte Valley Using Geostatistics and Geographic Information Systems

Research paper thumbnail of Influences of climate on aflatoxin producing fungi and aflatoxin contamination

International Journal of Food Microbiology, 2007

Research paper thumbnail of 25 Etiology and Management of Aflatoxin Contamination

Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and re- duce healt... more Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and re- duce health and economic welfare in several portions of Africa. Crops are contaminated in two phases: First, Aspergillus species infect crops during development; and second, after maturation contamination builds during exposure to warm humid conditions. Identification of the exact fungi causing contamination can provide clues to management strategies. Crops usually are infected by complex mixtures of aflatoxin-producing and closely related fungi. Among these are atoxigenic strains that produce no aflatoxins. In the United States atoxigenic strains are used to reduce contamination. Such technologies also may have value in Africa.

Research paper thumbnail of Etiology and management of aflatoxin contamination

Mycotoxins: detection methods, management, public health and agricultural trade, 2008

Research paper thumbnail of Aspergillus flavus diversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

Annals of the New York Academy of Sciences, 2012

Research paper thumbnail of Module storage time, leaf grade and seed moisture influence fiber quality and aflatoxin contamination of cotton in South Texas

Journal of cotton science, Mar 7, 2013

Research paper thumbnail of Etiology and management of aflatoxin contamination

Mycotoxins: detection methods, management, public health and agricultural trade, 2008

Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and reduce health ... more Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and reduce health and economic welfare in several portions of Africa. Crops are contaminated in two phases: (i) Aspergillus species infect crops during development; and (ii) after maturation contamination builds during exposure to warm humid conditions. Identification of the exact fungi causing contamination can provide clues to management strategies. Crops usually are infected by complex mixtures of aflatoxin-producing and closely related fungi. Among these are atoxigenic strains that produce no aflatoxins. In the United States atoxigenic strains are used to reduce contamination. Such technologies also may have value in Africa.

Research paper thumbnail of Aspergillus flavusdiversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

Annals of the New York Academy of Sciences, 2012

Research paper thumbnail of PLANT PATHOLOGY AND NEMATOLOGY Module Storage Time, Leaf Grade and Seed Moisture Influence Fiber Quality and Aflatoxin Contamination of Cotton in South Texas

Cotton is the most important natural fiber used to produce apparel, home furnishings, and industr... more Cotton is the most important natural fiber used to produce apparel, home furnishings, and industrial products. Cotton fiber quality influences both manufacturing efficiency and quality of the finished products. The color, length, strength, and purity of cotton fibers all contribute to fiber quality. Cottonseed is used as food (primarily oil) and is a preferred feed for dairy cows, with dairies paying a premium for cottonseed free of aflatoxin. Modules (14,200) of seed cotton grown in South Texas from 2002 through 2008 were analyzed for fiber quality and seed aflatoxin content. Harvest date, gin date, leaf grade, and seed moisture were related with fiber quality and seed aflatoxin content. Module storage time from harvest to ginning also influenced aflatoxin contamination and fiber quality. Standard fiber quality measurements, including lint color and spot, were related with aflatoxin content and, thus, might be useful predictors of seed aflatoxin contamination. Results suggest reduc...

Research paper thumbnail of Quantification of the Aflatoxin Biocontrol Strain Aspergillus flavus AF36 in Soil and in Nuts and Leaves of Pistachio by Real-Time PCR

Plant Disease

The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing ... more The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels, conditioning their sale. Strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCAs) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCAs are labor intensive and time consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on the sequence of aflC, a gene essential for aflatoxi...

Research paper thumbnail of Comparative effects of hermetic and traditional storage devices on maize grain: Mycotoxin development, insect infestation and grain quality

Journal of Stored Products Research

Research paper thumbnail of Resistance of maize land races from Mexico to aflatoxin contamination

Research paper thumbnail of Present Status and Perspective on the Future Use of Aflatoxin Biocontrol Products

Agronomy

Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and s... more Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and subtropical regions. The contamination is caused mainly by Aspergillus flavus and A. parasiticus. Aflatoxin contamination negatively affects health and trade sectors and causes economic losses to agricultural industries. Many pre- and post-harvest technologies can limit aflatoxin contamination but may not always reduce aflatoxin concentrations below tolerance thresholds. However, the use of atoxigenic (non-toxin producing) isolates of A. flavus to competitively displace aflatoxin producers is a practical strategy that effectively limits aflatoxin contamination in crops from field to plate. Biocontrol products formulated with atoxigenic isolates as active ingredients have been registered for use in the US, several African nations, and one such product is in final stages of registration in Italy. Many other nations are seeking to develop biocontrol products to protect their crops. In this r...

Research paper thumbnail of Applications of Geographic Information Systems and Geostatistics in Plant Disease Epidemiology and Management

Research paper thumbnail of Aspergillus flavus communities associated with commercial cottonseed in south Texas

Aspergillus flavus is the main causal agent of aflatoxin contamination of cottonseed. A. flavus c... more Aspergillus flavus is the main causal agent of aflatoxin contamination of cottonseed. A. flavus can be divided into two strains, S and L, based on physiological, morphological, and genetic criteria. Strain S isolates produce greater quantities of aflatoxins than L strain isolates in cottonseed. Aflatoxin contamination of cottonseed can be severe in South Texas. The structure of A. flavus communities associated with South Texas cottonseed was determined by analyzing 186 truckloads of commercial cottonseed sampled at the Valley Co-op Oil Mill in Harlingen, Texas from 1999 through 2001. The quantity of A. flavus (CFU) and the percent of A. flavus composed of the S strain were both correlated with aflatoxin contamination of South Texas cottonseed. CFU differed between both regions and seasons, while percent S only differed between regions. The Rio Grande Valley had significantly lower CFU and S strain than the Coastal Bend and Upper Coast regions. Cottonseed produced in 1999 had signifi...

Research paper thumbnail of Aflatoxin-producing fungi in maize field soils from sea level to over 2000 masl: A three year study in Sonora, Mexico

Research paper thumbnail of Crop rotation and soil temperature influence the community structure of Aspergillus flavus in soil

Soil Biology and Biochemistry, 2010

Research paper thumbnail of Aspergillus flavus in Soils and Corncobs in South Texas: Implications for Management of Aflatoxins in Corn-Cotton Rotations

Research paper thumbnail of Aflatoxin Contamination of Commercial Cottonseed in South Texas

Research paper thumbnail of Temporal and Spatial Patterns of Genetic Structure of Phytophthora infestans from Tomato and Potato in the Del Fuerte Valley

Research paper thumbnail of Spatial Analysis of Phytophthora infestans Genotypes and Late Blight Severity on Tomato and Potato in the Del Fuerte Valley Using Geostatistics and Geographic Information Systems

Research paper thumbnail of Influences of climate on aflatoxin producing fungi and aflatoxin contamination

International Journal of Food Microbiology, 2007

Research paper thumbnail of 25 Etiology and Management of Aflatoxin Contamination

Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and re- duce healt... more Aflatoxins are potent poisons that contaminate crops in warm regions worldwide and re- duce health and economic welfare in several portions of Africa. Crops are contaminated in two phases: First, Aspergillus species infect crops during development; and second, after maturation contamination builds during exposure to warm humid conditions. Identification of the exact fungi causing contamination can provide clues to management strategies. Crops usually are infected by complex mixtures of aflatoxin-producing and closely related fungi. Among these are atoxigenic strains that produce no aflatoxins. In the United States atoxigenic strains are used to reduce contamination. Such technologies also may have value in Africa.

Research paper thumbnail of Etiology and management of aflatoxin contamination

Mycotoxins: detection methods, management, public health and agricultural trade, 2008

Research paper thumbnail of Aspergillus flavus diversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

Annals of the New York Academy of Sciences, 2012