Weeds are a serious problem in agriculture, causing major losses in crop
production. Chemical methods for weed control, including herbicide use, may have a
harmful impact not only on untargeted plants but also on other beneficial organisms,
such as arbuscular mycorrhizal fungi (AMF), which form with plant roots, one of the
most widespread symbioses on Earth. AMF forms a profuse mycorrhizal mycelial
network that explores and scavenges the soil for nutrients and water and links
neighbouring plants, thus supporting the transfer of nutrients from one plant to another.
This chapter focuses on the interrelationships between weeds and cultivated plants
through mycorrhizal networks, as well as on possible herbicide-mediated changes in
fungal and plant communities. An overview of the influence of herbicides showing the
different modes of action on the formation and functioning of arbuscular mycorrhizal
(AM) symbiosis is given. Different issues, such as direct and indirect effects of
herbicides on the abundance and diversity of AMF, impact and species-specific
responses of AMF to herbicides, and other factors (i.e., mode of action, rate,
application method) influencing the effect of herbicides on the abundance and diversity
of AMF and AM formation are considered. The possible protective effect of AM
symbiosis on crops due to alleviation of herbicide-mediated stress is considered, which
could be an important clue for increasing herbicide efficiency. Indeed, in this sense, the
use of modern molecular biological tools seems promising.
Keywords: Arbuscular Mycorrhizal Fungi, Crops, Herbicides, Mycorrhizal Symbiosis, Weeds.
