Research on Dithianon to Evaluate Suspects of Reduced Sensitivity of Venturia inaequalis with Different Methodologies in Italian Apple Areas ()
ABSTRACT
Dithianon is a multi-site fungicide and has never
been object of suspects and reports of reduced sensitivity and activity.
Italian IFP technicians had the suspect of reductions of activity by this
fungicide on Venturia inaequalis. Methodologies, in vitro and in vivo were carried out to verify this
suspect. Populations poorly controlled with suspects on dithianon and sensible
ones were utilized. The tests in vitro permitted to evidence light and
non-significant reductions of sensitivity of poorly controlled populations with respect to sensible ones. In vivo tests on seedlings were non-reliable for a general low
activity of dithianon. On the contrary, the original in vivo methodology on grafted apple plants showed several
reductions of activity, with moderate levels and a spot distribution in orchards.
The cause was probably due to the increased treatments with dithianon caused by problems on
other groups of fungicides and by a high infective pressure in some years. It
is discussed if this reduction can be considered a resistance phenomenon or a
temporary modification of the interactions of plant-fungus-fungicide.
Share and Cite:
Riccardo, F. (2021) Research on Dithianon to Evaluate Suspects of Reduced Sensitivity of
Venturia inaequalis with Different Methodologies in Italian Apple Areas.
American Journal of Plant Sciences,
12, 406-416. doi:
10.4236/ajps.2021.123026.