POPULATION DYNAMICS OF PLANT PARASITIC NEMATODES IN DISTRICT BAHAWALPUR

Abstract

Plant-parasitic nematodes are among the most destructive soil-borne pests worldwide, causing substantial yield and economic losses in agricultural crops. They have a more influential effect in those areas where intensive systems of cropping are practiced. The subtropical climate and constant practice of vegetable farming in Pakistan favor the fast accumulation of nematodes, consequently root-knot nematodes (Meloidogyne spp.) have become a significant risk to vegetable production, particularly in Punjab. The aim of this study is the examination of the population, distribution, and pathogenicity of PPNs related to key vegetable plants in District Bahawalpur, Punjab, Pakistan. The systematic nematological survey was done in nine localities in which forty soil and root samples of eggplant, chilli, tomato, cucumber, and okra fields were carried out. Extraction and identification of nematodes were done under regular morphological and taxonomic methods such as permanent and temporary slide preparation. The host susceptibility was assessed using galling index and galling severity scales. Findings showed extensive nematode-infestation in all the localities surveyed with the levels of infection of between 50 and 86.67 with the highest prevalence occurring in Yazman. It was determined that there are six genera of invasive parasites of plants in this group of nematodes, but Meloidogyne incognita showed the most significant and destructive results, as it was found in 78 % of the samples M. javanica and Criconema spp. were also regularly occurring, whereas Xiphinema, Helicotylenchus and Pratylenchus spp. had irregular distribution patterns. The assessment of the pathogenicity showed that tomato and cucumber were the most affected, which severely rooted galled, and chilli was relatively less affected. The results suggest the serious menace of root-knot nematodes in the production of vegetables in Bahawalpur and the need to identify the species accurately and establish region-specific integrated approaches of managing the nematodes to minimize the loss of yield and assurance the production of the crop sustainably.