Sonchus arvensis L., commonly called perennial sow thistle, is
considered to be an important weed in Europe and North America.
It infests many habitats such as cultivated fields, roadsides, pastures
and lawns with consequent heavy economic losses. Most of the
herbicides recommended for the control of S. arvensis are generally
restricted to only a few active ingredients that tend to have low
selectivity, especially for dicots crops.1 Natural enemies of weeds such
as plant pathogens could be used for weed biocontrol as an ecofriendly
and quite selective support of crop protection measures.2
Two plant pathogenic fungi, Alternaria sonchi J.J. Davis and Phoma
exigua Desm. var. exigua have been considered as potential mycoherbicides
for S. arvensis.3