DNA sequence analysis of herbarium specimens facilitates the revival of Botrytis mali, a postharvest pathogen of apple.

The fungus Botrytis cinerea has been widely accepted as the species responsible for causing gray mold decay of apple, although a second species causing apple decay, B. mali, was reported in 1931. Botrytis mali was validly published in 1931, nevertheless it has always been considered a doubtful species.

Methodology for Determining Relationships Between Inoculum Concentration of Botrytis cinerea and Penicillium expansum and Stem End Decay of Pear Fruit.

The objective of this research was to determine quantitative relationships between incidence of stem end decay of pear fruit and inoculum concentration of Botrytis cinerea and Penicillium expansum using dry conidia applied to pear fruit in a settling tower. Five concentrations of conidia were applied to pear fruit, fruit were stored at -1°C for 8 months, and stem end decay was evaluated. In addition, conidia were washed from the surface of inoculated fruit, and DNA was extracted and quantified with real-time polymerase chain reaction (PCR).

Development of a DNA Macroarray for Detection and Monitoring of Economically Important Apple Diseases.

Short DNA gene sequences (oligonucleotides) from the ribosomal spacer regions of bacterial and fungal pathogens were used to identify and monitor economically important apple diseases. The oligonucleotides or probes were attached to a nylon membrane by an amine modified linker arm and arranged in a precise pattern to form an array for detecting five pathogens corresponding to five apple diseases. Initially the specificity of the probes was determined by hybridizing pure cultures of the pathogens to the probes.

Biological control of apple blue mold with Pseudomonas fluorescens.

Pseudomonas fluorescens isolate 1100-6 was evaluated as a potential biological control agent for apple blue mold caused by Penicillium expansum or Penicillium solitum. Both the wild-type isolate 1100-6 and a genetically modified derivative labeled with the gene encoding the green fluorescent protein (GFP) were compared. The P.

Effect of Preharvest Application of Cyprodinil on Postharvest Decay of Apples Caused by Botrytis cinerea.

Dry-eye rot and gray mold of apple are important diseases caused by Botrytis cinerea. Fungicides available for their control are lacking, and this study was conducted to determine if cyprodinil (Vangard) could be used for this purpose. The mean EC value of cyprodinil for 32 Botrytis spp.

Antimicrobial Activity of Gaseous Allyl Isothiocyanate.

A simple model system was constructed to evaluate the microbistatic and microbicidal properties of gaseous allyl isothiocyanate (AIT) against bacterial cells and fungal conidia deposited on agar surfaces. Salmonella typhimurium , Listeria monocytogenes Scott A, and Escherichia coli O157:H7 were inhibited when exposed to 1,000 μg AIT per liter. Pseudomonas corrugata , a Cytophaga species, and a fluorescent pseudomonad failed to grow in the presence of 500 μg AIT per liter.