Prevalence of plant-parasitic nematodes associated with tomatoes in three agro-ecological zones of Ghana
A study was conducted between August 2014 and May 2015 to identify plant-parasitic nematodes taxa associated with tomato (Solanum lycopersicum L.) and to assess the knowledge, perceptions and experiences of growers of the crop on occurrence and management of the parasites on their farms in nine communities within the semi-deciduous forest, the forest/savanna transitional and the savanna agro-ecological zones of Ghana. Semi-structured questionnaires were designed and administered to 54 randomly selected growers from the nine communities. Composite rhizosphere soil and tomato root samples were collected from two farms in each of the nine communities, and nematodes extracted, identified and recorded. The study revealed that many growers (73%) could not distinguish between nematode infestation, nutrient deficiency and moisture stress and, therefore, lacked knowledge on nematode control. Most of the growers (63%) continually cropped their land to tomato for periods of 4 –7 years without fallowing. All growers applied only inorganic fertilizer to their crops. Symptoms of nematode infestation were widespread in fields with high yield losses. Tomato was a host to Helicotylenchus spp. (11.5% in soil), Hoplolaimus spp. (1.0 % in soil), Meloidogyne spp. (37.4% in soil and 69.3% in roots), Pratylenchus spp. (20.6% in soil and 13.7% in roots), Rotylenchulus spp. (11.0% in soil and 12.2% in roots), Scutellonema spp. (9.5% in soil and 4.9% in roots), Tylenchus spp.(7.6% in soil) and Xiphinema spp.(1.4% in soil) across the nine communities surveyed. Semi-deciduous forest and Savanna agro-ecological zones had the highest and least population densities of nematodes, respectively. These nematodes, if not managed efficiently, could also serve as constraint to tomato production in the country.