TITLE:
Persistence of Venturia inaequalis Populations Resistant to Strobilurins in the Field and in the Glasshouse
AUTHORS:
Riccardo Fiaccadori
KEYWORDS:
Venturia inaequalis, Persistence, Resistance, Strobilurins, Scab Management
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.4,
March
7,
2018
ABSTRACT: The research was focused on the persistence of
resistance of V. inaequalis to
strobilurins from resistant populations occurring in the field. It was studied
with two types of experiments: the first in apple orchards where resistance
occurred in 2005 and employ of these fungicides was suspended from 2006 to
2011, realizing every year sensitivity/resistance assays on strobilurins. In
the second was verified the sensitivity/resistance of the same 2015
populations, repeatedly multiplied (ten inoculations) in glasshouse on apple
seedlings. Results showed that the resistance survived in orchards all the
years of tests (six years), despite sensitivity fluctuations occurred on
infected leaves due to sexual crosses, competition with sensible strains and
soil management. In glasshouse, the level of resistance of all populations
increased quickly in first inoculations and values remained high (EC50 > 10 mg·L-1) in all the following inoculations, until
the last, the 10th. V. inaequalis resistant strains seemed to show high fitness: relevant persistence in the
field, and a capacity of prevail on sensible ones in absence of factors of
field variability.