Strong synergistic activity and egg hatch inhibition by (E,E)-2,4-decadienal and (E)-2-decenal in Meloidogyne species

Recent research has been focused on the potential of plant natural products for the control of nematodes, but few studies are reported on synergistic interactions and egg hatch inhibition properties of botanicals. Herein, we evaluate the nematicidal activity of (E,E)-2,4-decadienal, 2-undecanone, furfural and (E)-2-decenal alone and in binary mixtures, on different Meloidogyne spp. and growth stages. (E,E)-2,4-decadienal exhibited strong paralysis activity on second-stage M. incognita,M. javanica and M. arenaria juveniles (EC50/4d = 8.06, 9.04 and 12.90 μg mL−1, respectively) and all its binary mixtures demonstrated synergy on all nematode species. (E,E)-2,4-decadienal best inhibited M. incognita undifferentiated egg hatch and J2 release from eggs immersed in 10 μg mL−1 solution. SEM experiments revealed malformations, in the form of constrictions, along the larvae body retained in eggs treated with (E)-2-decenal. Egg masses treated with 1 μg mL−1 solution of (E)-2-decenal released less than 50 % of the eggs if compared with the control. (E)-2-decenal and (E,E)-2,4-decadienal arrested M. incognita life cycle in pot bioassays (EC50 = 77.46 and 114.47 mg kg−1), with the latter additionally promoting tomato growth. Ailanthus altissima powder (AWP) and water extract (AWE), naturally containing (E,E)-2,4-decadienal and (E)-2-decenal, strongly arrested M. incognita life cycle in tomato plants, and AWP was far more active than AWE. Thus, we conclude that (E,E)-2,4-decadienal and (E)-2-decenal are promising nematicidal agents used alone, in artificial blends or as naturally present in botanical soil amendments.