First Report of Target Spot Caused by Corynespora cassiicola on Cotton in Tennessee

Genome sequences and SNP analyses of Corynespora cassiicola from cotton and soybean in the southeastern United States reveal limited diversity

“…At the time of sequencing we did not have access to isolates from surrounding states. Isolates from cotton included an isolate from Jackson, TN recovered in 2013 (used to report the first occurrence of target spot on cotton in Tennessee) and three isolates recovered from cotton in Jackson, TN in 2015 [ 29 ]. The isolate from soybean was recovered from Jackson, TN in 2015.…”

“…This could be due to the recent introduction of a highly successful clonal lineage of C . cassiicola to TN and surrounding states [ 9 , 27 , 29 ]. Development of additional SNP markers, using WGS from a wider array of isolates would be useful and the sequences presented here will be useful in this endeavor.…”

“…cassiicola is apparently new to the region and can produce copious airborne spores on foliar lesions. Further work characterizing the pathogen over time will be useful to track the epidemiology and monitor for cryptic sexual recombination and/or the introduction of novel clonal lineages [ 9 , 27 , 29 , 47 ].…”

“…Similarly, target spot can cause significant damage to cotton leaves resulting in premature defoliation [ 26 ]. Target spot is an emerging pathogen of cotton in the Southeastern US and has been reported in Georgia, Alabama, Louisiana, Mississippi, Arkansas, North Carolina and recently in Tennessee [ 9 , 21 , 27 – 29 ]. In highly susceptible cultivars, premature defoliation, starting from the lower canopy, can reach up to 75% and reduce the yield of seed cotton by 336 kg/ha [ 9 ].…”

The fungal pathogen Corynespora cassiicola: A review and insights for target spot management on cotton and Soya bean

“…In 1995, target spot was reported on upland cotton in Brazil but under the name Corynespora leaf spot (Mehta et al., 2005). The first occurrence and re‐emergence of the disease on upland cotton appeared from China (Wei et al., 2014), Brazil (Galbieri et al., 2014) and several states in the United States, including Georgia (Fulmer et al., 2012), Alabama (Campbell et al., 2012; Conner et al., 2013), Louisiana (Price et al., 2015) and Tennessee (Butler et al., 2016). Target spot has been a concern for farmers and researchers due to its increasing occurrence especially on Soya bean (Godoy, 2015) and cotton (Sumabat et al., 2018), owing to monoculture farming, adoption of conservation tillage systems, susceptibility of current cultivars, lack of crop rotation and optimal weather patterns for disease development (Avozani et al., 2014; Koenning et al., 2006).…”