Plant parasitic nematodes associated with Maize (Zea mays L.) in New Zealand

Abstract

Plant parasitic nematodes (PPNs) are a substantial threat to maize yield globally that is often underestimated. The presence and identification of PPN species in New Zealand maize production remain limited. This study aimed to identify the major PPNs, their population abundance, and distribution in New Zealand maize fields. A total of 384 soil samples were collected from 24 sites from the North (NI) and South Island (SI) of New Zealand in the maize for grain-growing regions of Canterbury (SI), Waikato (NI), and Manawatu (NI). Results showed that all samples were positive for at least one PPN genus. The major PPNs morphologically identified were Pratylenchus (91%), Helicotylenchus (38%), Meloidogyne (14%), Tylenchus (14%), Heterodera (8%), Paratylenchus (3%), and Criconemella (1%). Pratylenchus spp. was found to be extensively distributed in all three regions with populations above the economic threshold (1000 nematodes/kg of soil) in 8 of 9 sites in Canterbury (33% of samples) and 5 of 9 sites in Waikato (19%) and 3 of 6 sites Manawatu (19%). The maximum abundance of Pratylenchus spp. (15067 nematodes/kg soil) was detected in a Dorie maize field, Canterbury (SI). Sites of Rakia (2394 Pratylenchus/kg soil), Leeston (2106), and Dorie (1796) in Canterbury (SI), Ohaupo (1800), Tauhei (1000) ) in Waikato (NI) and Marton (2015) in Manawatu (NI) were identified as the “hotspots of Pratylenchus spp.”; where a site having a mean abundance of Pratylenchus/kg of soil above the reported economic threshold. The survey highlights the potential of Pratylenchus spp. to impact maize yield in major maize-growing regions in New Zealand. This study provides valuable insights into PPN communities in New Zealand maize fields and further research/s needs to be continued to develop effective PPN management strategies.