Plant Dis. 2023 Jun 17. doi: 10.1094/PDIS-10-22-2445-RE. Online ahead of print.
ABSTRACT
Options for managing southern blight of processing tomato (caused by Athelia rolfsii) in California are limited. The objectives of this study were to: (i) evaluate grafting with the resistant rootstock Maxifort for southern blight management in processing tomato; and (ii) evaluate increasing the height of the graft union to further reduce incidence of southern blight in grafted plants. We evaluated two cultivars (Heinz 5608 or Heinz 8504) and a grafting factor with three levels (grafted to Maxifort rootstock with standard scion height, grafted to Maxifort rootstock at a tall height, and non-grafted) in a field study with natural inoculum or in inoculated greenhouse experiments. Southern blight severity was low in both greenhouse experiments in 2018 and 2019 and no consistent trends were observed. In field experiments in 2018 and 2019, mean incidence in non-grafted plots was 6.2 to 17.0 times higher when compared to either the standard or tall grafted treatments. Southern blight was numerically lower in tall grafted plots compared to standard, but the magnitude was small and not statistically significant. Based on our studies, grafting can reduce losses of processing tomato in California to southern blight but increasing the height of the graft union does not offer a tangible benefit.
PMID:37330632 | DOI:10.1094/PDIS-10-22-2445-RE
