Evaluation of Root Knot and Reniform Nematode Resistant Phytogen Cotton Cultivars with Supplemental Corteva Agriscience Nematicides

A Phytogen cotton cultivar with resistance to the root-knot nematode (Meloidogyne incognita) became available to growers beginning in 2020, and the resistant reniform nematode (Rotylenchulus reniformis) cultivar is expected to be available to growers in 2021. The objectives of this study were: 1) to determine the benefit of a root-knot resistance variety PHY360 W3FE  and the reniform resistant variety PX3D32 in nematode infested fields, and 2) to determine the benefit of with the addition of  the nematicides Fluazaindolizine and Oxamyl. Field trials were established in nematode infested fields and arranged as a RCBD with five replications and the entire tests were repeated for a total of 4 trials.  To reduce root-knot and reniform nematode population levels, a Fluazaindolizine and Vydate (Oxamyl) mixture was applied at planting as an in-furrow spray. Field trials indicated that both root knot and reniform eggs per gram of root were significantly (P > 0.05) lower on the resistant cotton cultivars at 45 days after planting.  Root knot populations were reduced 84% by the PHY360 W3FE compared to PHY340 W3FE and reniform populations were reduced 78% by the PXD32 variety compared to PHY340 W3FE. The addition of a nematicide to both susceptible and resistant varieties further reduced nematode egg numbers.