Verticillium Wilt of Cotton: Identification and Detection of the Causal Pathogen and Its Control

<i>Verticillium wilt</i> (VW) of cotton caused by the soilborne pathogen <i>Verticillium dahliae</i> is a major disease across cotton production worldwide. The disease can result in yield reductions up to 80% on some occasions. <i>V. dahliae</i> is an asexual fungus and belongs to a relatively small <i>Verticillium</i> genus in the Ascomycota, though both of the mating type idiomorphs are present within some populations. The diversity of <i>V. dahliae</i> is widely associated with vegetative compatibility groups (VCGs), of which six different VCGs are recognised. Of these, isolates belonging to VCGs 1, 2, and 4 are globally distributed and associated with a broad host range, including cotton. Approximately 400 plant species have been recorded as hosts of <i>V. dahliae</i>. The pathogenicity and virulence of <i>V. dahliae</i> in many cases are correlated with VCG designations and hosts of origin. Disease management of VW of cotton still relies on accurate, rapid detection and quantification of <i>V. dahliae</i> using both conventional and molecular approaches. The use of resistant cultivars is the most effective and economical control strategy; however, no cultivars confer complete resistance to the disease. Control strategies including cultural, biological, chemical, and induced-resistance approaches have indicated certain degrees of success in minimising disease damage and diminishing the build-up of pathogen inoculum. In this review, we discuss insights into the VW disease of cotton, and the associated pathogen and current control approaches, as well as future research perspectives.