RA 00183.pdf - OAR@ICRISAT

Nematode D a m a g e to Groundnuts
and Rotation Crops in the West African Sahel
P. Baujard and B. Martiny 1
In the Sahelian region of West Africa, about 30 species of plant nematodes have been
identified in the groundnut rhizosphere in rotation crop systems (millet, cowpea, sorghum).
Field studies on the effect of nematocide in Sahelian crops have shown that the increase in
groundnut yields cannot be solely due to the destruction of nematodes. Recently, the stimulating
effect of dibromochloropropane on groundnut and cowpea plants has been demonstrated.
It is important, therefore, to obtain more precise data on the pathogenicity of the different
species of nematodes found in the rhizospheres of plants grown in the Sahelian region of
Senegal in order to use data that emerge from nematological analyses.
Current Findings
Factors Influencing Nematode Multiplication
In a study on the nematode Scutellonema cavenessi, it was found that soil temperatures, and
moisture content, the host plant in which the nematode lived its preceding cycle, the state of
the nematode (active versus anhydrobiotic), the duration of the anhydrobiotic life cycle, and
the duration of the preceding cycle have significant bearing on the multiplication rate of this
species. Laboratory findings confirmed the data obtained in the field.
The first pathogenic tests carried out on different crops show that these parameters also
appear to determine the extent of damage caused by the nematode.
Biotic and Abiotic Factors Affecting the Biology of the Nematode
In the Sahelian region of West Africa, the biotic and abiotic factors that affect the nematode
biology are:
• Temperature. Most species prefer temperatures of 34°C. Some species, particularly Pratylenchus
and Dorylaimid plant parasites multiply better at temperatures of 30-32°C. Only
one species, Scutellonema clathricaudatum identified in the eastern region of Mali prefers
high temperatures of around 36°C.
1. Charge des recherches; Technician (nematologie), ORSTOM, Laboratoire de Nematologie, B.P. 1386, Dakar,
Senegal.
Citation: ICRISAT (International Crops Research Institute for the Semi-Arid Tropics). 1991. Summary Proceedings of
the Second ICRISAT Regional Groundnut Meeting for West Africa, 11-14 Sep 1990, ICRISAT Sahelian Center,
Niamey, Niger. Patancheru, A.P. 502 324, India: ICRISAT.
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