Incidence, Prevalence And Management Of Root-Knot Nematodes (Meloidogyne Spp.) On Selected Indigenous Leafy Vegetables In Kisii And Trans-Mara Counties, Kenya

ABSTRACT

Solanum nigrum L., Cleome gynandra L. and Amaranthus spp. are some of the indigenous leafy vegetables (ILVs) that contribute to food diet, income generation, good nutrition and health to resource-poor farmers in Kisii and Trans-Mara counties. The production of ILVs is constrained by inadequate land, diseases and pests of which, root-knot nematodes (RKN) are the most damaging pests to vegetable crops causing about 30 % yield losses globally. However, there is no information about the incidence, prevalence and management of RKN on ILVs in Kenya or worldwide. A survey was conducted in Kisii and Trans-Mara to determine the incidence and prevalence of RKN in ILVs and the available germplasms were screened for response to Meloidogyne spp. in greenhouse. Five organic amendments (OAs) commonly used in the areas of study for ILVs cultivation were also evaluated for their effects on RKN on C. gynandra, S. nigrum, S. villosum and Amaranthus spp. in greehouse and field tests. The amendments included: tea (Camellia sinensis (L.) Kuntze) residues (Tres) and rejects (Trej), decomposed cattle manure (CM), goat manure (GM) and Tithonia diversifolia manure (Td). The amendments were incorporated into the sterilized soil in micro-pots and the field at recommended rates. Unamended soils served as controls. After ninety (90) days, the disease and plant growth parameters were assessed. The study revealed that, 62.8 % of the farms surveyed were infected with RKN. The disease incidence was generally higher in the black nightshades from Kisii compared to those from Trans-Mara, while disease incidence in spider plants and amaranths was generally higher in Trans-Mara compared to Kisii Counties. Black nightshades were susceptible to RKN with green berried recording higher reproduction and galling index compared to susceptible check, while amaranths and spider plants had lower scores (