Survey and identification of plant parasitic nematodes in vegetable growing areas

Abstract:

Imagine losing a quarter of your tomato harvest to an enemy you cannot see—plant parasitic nematodes operate below the soil surface, causing root galling, stunting, and yield decline that farmers often mistake for nutrient deficiency. This research surveyed 72 vegetable fields across six wards of Morogoro Rural District, Morogoro Region, during March-August 2024 to identify the species composition, population density, and host associations of plant parasitic nematodes in the major vegetable crops of the region. Soil and root samples were processed by Cobb’s sieving and Baermann funnel extraction, and nematodes were identified to genus or species using morphological keys. Six genera were recorded, with Meloidogyne incognita being the most frequent (84.3% of fields) and most abundant (mean 342 individuals per 200 cm³ soil in tomato). Tomato harboured the highest nematode populations, followed by brinjal (287) and cucurbits (231). Root-knot indices reached grade 4-5 in 38.9% of tomato fields. The findings provide a baseline pest inventory that can guide nematode management recommendations for vegetable growers in the region.