thiophanate and iprodione

Topics: Aminoimidazole Carboxamide; Aminopyridines; Ascomycota; China; Dioxoles; Drug Resistance, Fungal; Fungal Proteins; Fungicides, Industrial; Gene Expression Regulation, Fungal; Hydantoins; Mutation; Pyrroles; Thiophanate; Triazoles

Botrytis fruit rot, caused by Botrytis cinerea, is one of the most important strawberry diseases worldwide, and fungicide applications are often used to manage the disease in commercial production. Isolates of B. cinerea were collected from conventional and organic strawberry fields in four Brazilian States from 2013 to 2015 and their sensitivity to the main single-site mode-of action fungicides used in Brazil was tested. Resistance to azoxystrobin, iprodione, pyrimethanil, and thiophanate-methyl was found and values for effective concentration that inhibited mycelial growth by 50% were higher than 71.9, 1.2, 5.0, and 688 µg/ml, respectively, regardless the production system. Resistance to these fungicides was observed in 87.5, 76.6, 23.4, and 92.2% of isolates from conventional fields and 31.4, 22.9, 14.3, and 51.4% of isolates from organic fields, respectively. Moreover, frequencies of isolates with multiple fungicide resistance to the four active ingredients were 20.6 and 2.8% whereas 6.3 and 27.8% were sensitive to the four fungicides for conventional and organic areas, respectively. Molecular analyses of the cytochrome b, β-tubulin, and bos1 genes revealed the presence of G143A; E198A; and I365 N/S, Q369P, or N373S mutations, respectively, in resistant isolates of B. cinerea. Field rates of fungicides sprayed preventively to inoculated strawberry fruit failed to control disease caused by the respective resistant isolates.

Topics: Aminoimidazole Carboxamide; Botrytis; Brazil; Drug Resistance, Fungal; Fragaria; Fruit; Fungicides, Industrial; Hydantoins; Plant Diseases; Pyrimidines; Strobilurins; Thiophanate

There is currently a lack of reliable information on the exposures of residents and bystanders to pesticides in the UK. Previous research has shown that the methods currently used for assessing pesticide exposure for regulatory purposes are appropriate for farm workers 1. However, there were indications that the exposures of bystanders may sometimes be underestimated. The previous study did not collect data for residents. Therefore, this study aims to collect measurements to determine if the current methods and tools are appropriate for assessing pesticide exposure for residents living near agricultural fields.. The study will recruit owners of farms and orchards (hereafter both will be referred to as farms) that spray their agricultural crops with certain specified pesticides, and which have residential areas in close proximity to these fields. Recruited farms will be asked to provide details of their pesticide usage throughout the spray season. Informed consenting residents (adults (18 years and over) and children (aged 4-12 years)) will be asked to provide urine samples and accompanying activity diaries during the spraying season and in addition for a limited number of weeks before/after the spray season to allow background pesticide metabolite levels to be determined. Selected urine samples will be analysed for the pesticide metabolites of interest. Statistical analysis and mathematical modelling will use the laboratory results, along with the additional data collected from the farmers and residents, to determine systemic exposure levels amongst residents. Surveys will be carried out in selected areas of the United Kingdom over two years (2011 and 2012), covering two spraying seasons and the time between the spraying seasons.. The described study protocol was implemented for the sample and data collection procedures carried out in 2011. Based on experience to date, no major changes to the protocol are anticipated for the 2012 spray season although the pesticides and regional areas for inclusion in 2012 are still to be confirmed.

Topics: Adolescent; Adult; Agriculture; Aminoimidazole Carboxamide; Captan; Child; Child, Preschool; Chlormequat; Chlorpyrifos; Diquat; Environmental Exposure; Environmental Monitoring; Humans; Hydantoins; Nitriles; Pesticides; Pyrethrins; Risk Assessment; Seasons; Thiophanate; Triazoles; United Kingdom

The benzimidazole fungicide thiophanate-methyl is commonly applied to control leaf mould of tomato caused by Cladosporium fulvum in China. In this study, 32 isolates of C. fulvum were examined for their sensitivities to thiophanate-methyl, and two benzimidazole-resistant (BenR) phenotypes BenR1 and BenR2 were identified. The BenR1 isolates were resistant to thiophanate-methyl, but were more sensitive to the phenylcarbamate fungicide diethofencarb than the wild-type isolates. The BenR2 isolates resistant to thiophanate-methyl were insensitive to diethofencarb. All tested isolates were sensitive to the dicarboximide fungicide iprodione. The complete beta-tubulin gene was isolated from this fungus to study its potential role in benzimidazole resistance. Analysis of the DNA sequence of the beta-tubulin gene showed that the BenR1 isolates had a point mutation at codon 198, causing a substitution of glutamic acid to alanine. In the BenR2 isolates, a point mutation at codon 200 causing a substitution of phenylalanine to tyrosine was detected. Based on these point mutations, a multiplex allele-specific PCR method was developed successfully for the first time to detect two point mutations at the beta-tubulin gene simultaneously in single PCR amplifications.

Topics: Aminoimidazole Carboxamide; Benzimidazoles; Cladosporium; Codon; Drug Resistance, Fungal; Fungicides, Industrial; Hydantoins; Phenylcarbamates; Point Mutation; Polymerase Chain Reaction; Thiophanate; Tubulin

Topics: Aminoimidazole Carboxamide; Carbamates; Fungi; Fungicides, Industrial; Hydantoins; Plant Diseases; Plants; Thiophanate