園芸ジャーナル
オープンアクセス

概要

Abiotic Factor Influence to Density and Distribution of Plant-Parasitic Nematodes on Citrus in Kenya

Judith J. Kiptoo, Paul N. Ndegwa, Daniel L. Mutisya, Ruth Amata, Lucy Irungu, Gaudencia J. Kiptoo

Plant-parasitic nematodes (PPNs) pose threat to agricultural production and food security globally. They cause major crop losses by damaging the roots and causing plant diseases. Various PPNs species require adequate attention since they damage and limit production in citrus. Their taxonomy is very important for management strategies. A two-year survey in 2018 and 2019 was conducted in all citrus-growing regions in Kenya to assess the abundance, distribution, and diversity of plant-parasitic nematodes from the soil rhizosphere. Nematode population in 200cc of soil and 5g of roots was determined by extraction using modified Baermann’s technique and identification by morphological features. The findings indicated that four genera were encountered in different citrus growing county regions in Kenya. The PPNs species identified were Meloidogyne incognita, Tylenchulus semipenetrans, Helicotylenchus dihystera and Pratylenchus brachyurus. The most predominant species in all the surveyed localities was Tylenchulus semipenetrans. Factor regression analysis results showed that modest rainfall amounts favored high-density counts of PPNs on citrus root where soil types of Rackers in Baringo and Luvisols, Ferralsols, and Cambisols in Machakos County were dominant. Species of Tylenchulus, Meloidogyne, and Helicotylechus were most abundant in Kitale, Taita-Taveta, Kilifi, and Kwale. The results presented here show how possible the population density of PPNs in varied soil types, rainfall amounts, and prevailing temperature would be influenced by abiotic factors therein. Hence appropriate approaches to manage the PPNs species damaging citrus roots are important.