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Sensitivity of Venturia inaequalis to trifloxystrobin
Author(s) -
Küng Färber Ruth B,
Chin Khoon Min,
Leadbitter Neil
Publication year - 2002
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.443
Subject(s) - venturia inaequalis , apple scab , biology , spore , strobilurin , conidium , germination , spore germination , horticulture , botany , fungicide , azoxystrobin
The sensitivity of Venturia inaequalis to trifloxystrobin was monitored by both in vitro (spore germination) and in vivo tests (on apple seedlings). There was good correlation between the in vitro and in vivo results. Baseline sensitivity was established with 95 bulk isolates from Europe between 1995 and 1998 which showed a narrow sensitivity range‐factor of up to 17 between the least and most sensitive isolates. Monitoring of populations originating from trifloxystrobin‐treated and untreated orchards between 1995 and 1999 showed only sensitive isolates and no performance deficiencies were reported. Data also show that trifloxystrobin is not cross‐resistant to anilinopyrimidines and triazoles, but is cross‐resistant to kresoxim‐methyl, another strobilurin which also inhibits the cytochrome bc1 enzyme complex at the Qo‐site in the respiration chain of fungal mitochondria (QoI inhibitors). Under experimental conditions from a specific trial site in Switzerland, where trifloxystrobin has been tested since 1994, isolates containing conidia resistant to Qo inhibitors were detected in 1997 and 1999. However no obvious performance deficiencies were reported. Nevertheless these results demonstrate a risk for the development of practical resistance in V inaequalis to Qo inhibitors and therefore a need to apply resistance management principles strictly. © 2002 Society of Chemical Industry