Papaya latex and papain as promising solutions for the management of Meloidogyne javanica associated with tomato plants

Abstract

Nematodes from the Meloidogyne genus present a major challenge to agricultural progress, requiring control methods that are environmentally safe and human friendly. This study assessed the nematicidal effects of papaya latex and papain, both in vitro and in vivo, on tomato plants, targeting second-stage juveniles (J2s) and eggs of Meloidogyne javanica. The results demonstrated that papaya latex effectively increased J2 mortality, reaching 100% at the highest concentration (1%). In contrast, papain resulted in a maximum J2 mortality of 72% at its highest concentration (3.5%). Additionally, papaya latex consistently inhibited egg hatching, with an average reduction of 45% in the first experiment and reductions of 39% and 61.9% in the second experiment at concentrations of 1.5% and 3%, respectively. Similarly, papain suppressed egg hatching at all concentrations, leading to an average reduction of 44% in the first experiment and 55% in the second. In the first replication of the in vivo experiment with tomato plants, the highest concentration of papaya latex (4%) reduced M. javanica infectivity by 68% and reproduction by 89%. In the second experiment, this concentration reduced infectivity by 70% and reproduction by 80%. For papain, infectivity was reduced by 55% in the first experiment and 40% in the second. While reproduction did not differ significantly between treatments and the control in the first experiment, it decreased by 30% in the second. Further experiments showed that both papaya latex and papain effectively activated the plant defense system in tomato. Overall, these findings add to the growing body of evidence supporting the use of natural compounds for sustainable nematode management.