Distribution and Occurrences of Parasitic Nematodes Associated with Beans (Phaseolus vulgaris L.) in the Sotuba Market Gardening Area in Mali

A nematological faunistic study was carried out on common bean plots in Bamako between June and September 2023. It took place on the experimental plots of the fruit and vegetable program of the Sotuba Agricultural Research Center. The objective of the study was to identify the occurrence of nematode genera associated with beans. Two varieties of beans were concerned: Blanc de Kati and GLP. The trials were set up on two 400 m2 plots and ten samples were taken using a systematic method using an auger. In the laboratory, two extraction techniques were used: sieving and the modified Baermann technique. Plant-parasitic nematodes were observed and identified under an optical microscope at x400 magnification. The observations revealed the presence of 8 genera of nematodes in the soil and 6 in the roots. The genera found in the soil are: Scutellonema, Tylenchorhynchus, Paratylenchus, Helicotylenchus, Meloidogyne, Pratylenchus Criconemella and Hoplolaimus). Those found in the roots were Scutellonema, Paratylenchus, Helicotylenchus, Meloidogyne, Heterodera and Pratylenchus). The analysis of the results shows that the genera Pratylenchus Tylenchorhynchus and Helicotylenchus are the most important with 69% of the nematodes identified. Among the nematodes identified were species dangerous for crops in general, including Meloidogyne. Analysis of physicochemical parameters indicates a trend of variation in the distribution of nematodes depending on the soil structure This study demonstrates the need to monitor pest thresholds to prevent extreme outbreaks that can cause significant yield declines.