Micronutrient Nanoparticles in the Control of Meloidogyne javanica in Soybean

Nanoparticles (NP) are being introduced into agriculture as biopesticides and biofertilizers. There are hypotheses that micronutrients may have a more pronounced effect in the form of NP. This study aimed to investigate the potential of micronutrient NP in controlling Meloidogyne javanica in soybean. Experiment 1 comprised two trials conducted in pots in a greenhouse to assess the effect of ZnO, MnO, and FeO NP, their bulk equivalents, and sulfate salts on nematode control and soybean development. Zn reduced the number of nematode eggs per gram of root by approximately 40% relative to the control, regardless of the sources. In Experiment 2, two trials were performed to evaluate the effect of different doses and sources of Zn on nematode reproduction and crop development. Overall, ZnO NP did not differ from other Zn sources (Trial 1). In Trial 2, it was estimated that the maximum control (42.10%) would be obtained with 1087 mg L− 1 ZnO NP. At a dose of 500 mg L− 1, ZnO NP resulted in a greater reduction (48.21%) in total number of eggs than ZnSO4 and bulk ZnO. Experiment 3 was conducted to assess the effect of optimal doses of Zn on the lignin content of soybean roots. Lignin content increased under ZnO NP and bulk ZnO treatments. It was concluded that Zn helps reduce M. javanica reproduction on soybean, with ZnO NP having a similar action to their bulk counterpart. These effects are believed to stem from an increase in root lignin content, hindering nematode activity. Keywords Iron · Lignin · Manganese · Metallic nanoparticles · Root-knot nematodes · Zinc