Relative susceptibility of common cotton cultivars to Meloidogyne enterolobii, M. floridensis, and M. incognita isolates from Georgia, USA

Authors: AFROZ, TANIA - University Of Georgia; GORNY, ADRIENNE - North Carolina State University; KEMERAIT, ROBERT - University Of Georgia; Davis, Richard; CHOWDHURY, INTIAZ - University Of Georgia

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2025
Publication Date: 2/23/2026
Citation: Afroz, T., Gorny, A., Kemerait, R.C., Davis, R.F., Chowdhury, I.A. 2026. Relative susceptibility of common cotton cultivars to Meloidogyne enterolobii, M. floridensis, and M. incognita isolates from Georgia, USA. Phytopathology. 116:429-435. https://doi.org/10.1094/PHYTO-07-25-0240-R.
DOI: https://doi.org/10.1094/PHYTO-07-25-0240-R

Interpretive Summary: Cotton is a major crop in the southern United States where the Southern root-knot nematode, Meloidogyne incognita, is its most significant pathogen. Recently, two additional root-knot nematodes, M. floridensis and M. enterolobii have been reported in Georgia. Due to the lack of resistance in cotton cultivars to M. floridensis and M. enterolobii, we conducted a greenhouse study to evaluate the susceptibility of twelve cotton varieties to M. enterolobii, M. floridensis, and M. incognita. A susceptible tomato cultivar, 'Rutgers,' was included for comparison because it is known to allow significant levels of reproduction for all three species. Three-week-old cotton plants were inoculated with isolates of the three nematode species (5,000 eggs per plant). Plant shoot fresh weight, root fresh weight, gall rating (0-10 scale), egg count/root system and reproduction factor (RF) were determined. RF is a measure of how much the population increased during the experiment: an RF < 1 means the population declined. Out of the twelve cotton cultivars evaluated, seven cultivars (DG3644B3XF, PHY411W3FE, ST5091B3XF, PHY400W3FE, PHY443W3FE, PHY1150W3FE, and PHY330W3FE) were resistant to M. floridensis (RF < 1). Additionally, six cultivars (DG3644B3XF, PHY400W3FE, DP2141B3XF, PHY443W3FE, PHY545W3FE, and PHY411W3FE) exhibited resistance to M. incognita (RF < 1). However, no resistant cultivars were identified for M. enterolobii. Among the nematode species, M. enterolobii had the most reproduction, followed by M. floridensis and M. incognita.

Technical Abstract: Cotton is a major crop in the southern United States, with Meloidogyne incognita being its most significant pathogen. Recently, Meloidogyne floridensis and Meloidogyne enterolobii have been reported in Georgia. Due to the lack of resistance in cotton cultivars to M. floridensis and M. enterolobii, we conducted a greenhouse study to evaluate the susceptibility of twelve cotton varieties to M. enterolobii, M. floridensis, and M. incognita. A susceptible tomato cultivar, 'Rutgers,' was included as a positive control. Three-week-old cotton plants were inoculated with isolates of M. incognita, M. enterolobii, or M. floridensis (5,000 eggs per plant) and arranged in a randomized complete block design with six replications. Plant shoot fresh weight, root fresh weight, gall rating (0-10 scale), egg count/root system and reproduction factor (RF) were determined. Out of the twelve cotton cultivars evaluated, seven cultivars (DG3644B3XF, PHY411W3FE, ST5091B3XF, PHY400W3FE, PHY443W3FE, PHY1150W3FE, and PHY330W3FE) were resistant to M. floridensis (RF < 1). Additionally, six cultivars (DG3644B3XF, PHY400W3FE, DP2141B3XF, PHY443W3FE, PHY545W3FE, and PHY411W3FE) exhibited resistance to M. incognita (RF < 1). However, no resistant cultivars were identified for M. enterolobii. Among the nematode species, M. enterolobii was the most aggressive, followed by M. floridensis and M. incognita.