Non-fumigant nematicides are promising alternatives to fumigants for the management of Meloidogyne enterolobii in tobacco

Authors: ALAM, S - Clemson University; KHANAL, CHURAMANI - Clemson University; Rutter, William; ROBERTS, JOSEPH - Clemson University

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2022
Publication Date: 11/8/2022
Citation: Alam, S., Khanal, C., Rutter, W.B., Roberts, J. 2022. Non-fumigant nematicides are promising alternatives to fumigants for the management of Meloidogyne enterolobii in tobacco. Journal of Nematology. 54(1):3922. https://doi.org/10.2478/jofnem-2022-0045.
DOI: https://doi.org/10.2478/jofnem-2022-0045

Interpretive Summary: Meloidogyne enterolobii is a species of plant parasitic root-knot nematode that has been spreading across the southern US in recent years. US tobacco farmers have traditionally used a combination of fumigant nematicides and genetically resistant host plants to manage other species of root-knot nematodes in their fields. Unfortunately, the the currently available host resistance in tobacco cultivars is not effective against M. enterolobii, and many of the most effective fumigants have been banned or severely restricted due to environmental concerns. Several non-fumigant chemical nematicides including oxamyl, fluopyram, and fluensulfone are commercially available, as well as a biological nematicide (Majestene), but none of these potential alternatives have been tested for their ability to control M. enterolobii on tobacco. In this study we conducted replicate growth chamber assays to test the efficacy of these 4 non-fumigant nematicides to reduce M. enterolobii galling and reproduction on tobacco. Our results show that all 3 chemical nematicides have the abillity to suppress galling and reproduction by 94% or more compared to controls, while no effect was observed for the biological control. Results from this study suggest that non-fumigant nematicides have a potential to serve as an alternative to fumigant nematicides.

Technical Abstract: Experiments were conducted to evaluate the efficacy of three currently available non-fumigant chemical nematicides (oxamyl, fluopyram, and fluensulfone) and a biological nematicide derived from Burkholderia (Majestene) against Meloidogyne enterolobii on tobacco in a growth room environment. The non-fumigant chemical nematicides greatly suppressed nematode egg production compared to the untreated control, the suppression being 99.9% for fluensulfone and oxamyl, and 93% for fluopyram. Similarly, oxamyl, fluensulfone, and fluopyram treated pots, respectively, had 99%, 98%, and 94% less J2/100 cm3 of soil compared to those in control. The biological nematicide did not have a significant effect on nematode egg production as well as the soil abundance of J2. The root biomass of tobacco was significantly reduced by the application of fluensulfone while the effects of oxamyl, fluopyram, and Majestene were not significant compared to the untreated control. Results from this study suggest that non-fumigant nematicides have a potential to serve as an alternative to fumigant nematicides.