Influence of Seasonal Variations on Population Dynamics of Phyto-Parasitic Nematodes in Soil and Roots of Bell Pepper (Capsicum annuum L.) in Otari, Rivers State, Nigeria

Abstract

Weather instability affects nematode proliferation in soil, affecting plant growth. Identifying endemic species and favourable seasons can guide farmers in cultivating crops during specific seasons, minimizing infections and improving yield. A survey to evaluate the influence of seasonal disparity on plant parasitic nematodes population in soil and roots of bell pepper (Capsicum annuum L.) was carried out during dry and rainy seasons in Otari, Abua/Odual Local Government Area of Rivers State, Nigeria. Five bell pepper cultivated fields were randomly selected and a total of 300 soil samples were collected and assayed for soil nematodes. The soil samples were collected using a soil auger at 0-15 cm depth, and roots were collected by the use of sterilized kitchen knife simultaneously for the isolation of nematode. The modified sieve plate method was employed for the extraction of nematodes. Nematode identification was carried out using a pictorial key. A total of 2,220 nematodes from 11 genera were reported in this study, among which 1,290 (58.1%) were recovered during the rainy season while the dry season showed 930 (41.9%) nematodes. Nematode population vary significantly between seasons in soil (P = .13) and roots of bell pepper (P = 3.90), with Heterodera species having higher density (1.44 and 1.03) during the rainy and dry seasons respectively in the soil. High density of Meloidogyne (0.97) was recorded during the rainy season and Radopholus spp (1.40) during the dry season in the root of bell pepper plant. The study showed that seasonal variations impacted on nematode population abundance in fields, establishing that nematodes are responsive to every unsteady condition of the soil environment resulting from seasonal disparity, and only species who adapt rapidly survive. Farmers should increase crop cultivation during the rainy season to boost yield, as nematodes population decline as rainfall increases.