Publications by authors named "Michael A Yoshimura"

Monilinia laxa is a pathogen of brown rot of stone fruit and almond in California, causing blossom blights and fruit rots. In this study, low-level resistance to the benzimidazole fungicides benomyl and thiophanate-methyl was detected in field isolates of M laxa collected from stone fruits and almonds in California. Low-resistant (LR) isolates grew in potato dextrose agar (PDA) plates amended with benomyl and thiophanate-methyl at 1 and 5 microg ml(-1), respectively, but not in plates amended with benomyl at 5 microg ml(-1) or thiophanate-methyl at 50 microg ml(-1).

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Sensitivity in Monilinia fructicola to three fungicides was determined by measuring mycelial growth in fungicide-amended media. Resistance to thiophanate-methyl was found in 39 of 52 isolates (75%) collected from 1992 to 1998 (historic population) and 22 of 100 isolates (22%) collected in 2002 (current population). Three groups having distinct ranges of values for 50% effective concentration (EC) to thiophanate-methyl were identified.

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Low and high levels of resistance to the benzimidazole fungicides benomyl and thiophanate-methyl were observed in field isolates of Monilinia fructicola, which is the causative agent of brown rot of stone fruit. Isolates that had low levels of resistance (hereafter referred to as LR isolates) and high levels of resistance (hereafter referred to as HR isolates) were also cold and heat sensitive, respectively. Results from microsatellite DNA fingerprints showed that genetic identities among the populations of sensitive (S), LR, and HR isolates were very high (>0.

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