Effect of the herbicide ametryn on cellulose-deeomposing fungi in Egyptian soil

Ametryn exerted a depressive effect on the total count of cellulose-decomposing fungi after 1 and 3 weeks of treatment with a high dose (54 mg active ingredient per kg dry soil), and 5 weeks after treatment with medium (27 mg) and high doses. This inhibitory effect was alleviated after 8 weeks, while after 12 weeks it was changed into promotion by a low dose (5.4 mg). When incorporated in the agar medium, this herbicide was toxic to the total count and to the counts of almost all fungal genera and species at the three doses (25, 125, 250 ppm). The decomposition of ametryn-treated calico buried in untreated soil was significantly and regularly inhibited by medium and high doses after all experimental periods. The growth and sporulation of test fungal species were partially or completely inhibited by the three doses, except,Aspergillus niger, Chaetomium globosum, andGliocladium roseum which were not affected by the low dose