Efficacy of Chemical and Biological Nematicides against Root Knot and Sting Nematodes in Watermelon and Tomato

Abstract

In agricultural ecosystems, plant-parasitic nematodes are significant pests that affect crop health and productivity. This study evaluated the efficacy of various nematicides, both biological and chemical, against root-knot nematodes (Meloidogyne spp.) (RKN) and sting nematodes (Belonolaimus longicaudatus) (SN) in Honduras and the State of Florida in the United States. Root-knot nematode experiments were conducted on watermelon (Citrullus lanatus) and tomato (Solanum lycopersicum), while the SN experiment was conducted on tomato. In Honduras, treatments included biological nematicides (i.e., Paecilomyces lilacinus, Trichoderma harzianum) and chemical nematicides (i.e., fluensulfone, oxamyl, fluopyram), and in Florida, biological nematicides (i.e., Purpureocillium lilacinum strain PL11, Bacillus amyloliquefaciens strain D747, vegetable extracts (cinnamon, clove and thyme oil)) and chemical nematicides (i.e., fluopyram). The variables measured were fresh and dry shoot weight, height, root gall ratings, number of eggs in roots, and second-stage juveniles in soil for RKN, and number of nematodes in soil and rhizosphere for SN. Results from the Honduras trial showed that fluensulfone and oxamyl were the most effective treatments (P <0.05), significantly reducing the RKN population. In the Florida trial, fluopyram showed the highest efficacy (P <0.05) in reducing RKN. No significant reduction in SN was noted for any of the treatments, but the experiment confirmed that tomato is a good host for SN.