Prevalence and abundance of plant-parasitic nematodes associated with corn (Zea mays L.) in Anuradhapura, Sri Lanka

Abstract

Plant parasitic nematodes (PPN) are important pests of corn (Zea mays L.) Globally, while corn production has recently expanded in Sri Lanka. The population abundance, distribution, and pathological effects of nematodes that adversely affect corn production in Sri Lanka are poorly understood. This study was conducted to identify the prevalence of major PPN genera, population abundance, and their reproduction associated with corn fields in the Anuradhapura district. Over 92% of the corn fields were positive for PPN from the fields sampled in February 2021. Major PPN genera identified were Pratylenchus (71.4%) Helicotylenchus (28.6%), Meloidogyne (21.4%), Criconemella (21.4%), and Hoplolaimus (35.7%). The mean population of the Pratylenchus was 2020 kg-1 of soil, which was above the threshold level (1000 Pratylenchus kg-1 of soil), while other genera were lower than the threshold. All genera, except Meloidogyne, were observed from the intensive sampling from the selected fields during the next cropping season from November 2021 (seedling stage) to February 2022 (harvesting stage). Pratylenchus abundance in all the fields was lower than the threshold at the seedling stage and it was 2 to 10 times higher during the harvesting stage, except in Kelenikawewa where the initial Pratylenchus population (1865 kg-1 of soil) was also above the threshold. According to our results, Pratylenchus have the potential to impact corn yield in Anuradhapura. Future field experiments will determine the impact of PPN on corn production in Sri Lanka.