Résumé:
The study of the state of infestation of grain fields at some wilayas in Algeria by the cyst nematode Heterodera sp. shows that all the surveyed cities are infested by this parasite.
Furthermore, the values of the densities (number of cysts/100 g soil) do not reflect the actual state of a plot infestation. Indeed, we found that the densities recorded Djendel (Ain Defla)
(2,3 cysts/100 g soil) and Oued Smar (Alger) (2,35 cysts/100 g soil) are very close to the from each other. By cons, comparing their respective degrees of infestation (7.8 and 4.6 L2/g soil) shows a clear difference regarding the state of infestation of their plot. The isolation of the
microflora from Heterodera sp. cysts allowed us to identify six fungi Fusarium sp.,
Ulocladium sp., Penicillium sp., Aspergillus sp., Rhizopus sp. and Rhizomucor sp. and a bacteria, namely Erwinia sp.. The use of two fungi Fusarium sp. and Ulocladium sp. in direct
confrontation with the eggs of two populations of Heterodera sp. (Mouzaïa and Dahmouni)
revealed an antagonistic effect against the nematode..
