SIDE EFFECTS OF PESTICIDES ON NON-TARGET SOIL ASPERGILLI.

Aspergilli constitute the largest fungal group present in all types of soil and also contribute in maintaining the soil structure and fertility. Fungicides that are used to control fungal plant pathogens may also be toxic to beneficial soil fungi. The present study was conducted to assess the impact of seven broad-spectrum fungicides namely Tebuconazole, Bloom, Benedict, Epic, Primacy and Hiten on growth of five different species of Aspergillus namely A. nidulans (Eidam) Wint., A. niger Tiegh., A. terreus Thom., A. fumigatus Fresen. and A. flavus Link. The results of the current study presented a comprehensive overview of the negative effects of fungicides on growth of commonly found soil Aspergilli. With the increasing concentration of all the tested fungicides from 0 to recommended dose (R), a gradual reduction in growth of all the fungal species was observed. Hiten and Epic were most effective in controlling the growth of Aspergillus spp. by causing complete growth arrest at only 0.05R. Bloom ceased the growth at one fourth of the recommended dose (0.25R). No growth of the A. niger, A. terreus, A. fumigatus and A. flavus was observed at 0.75R and that of the A. nidulans at recommended dose of Tebuconazole. In case of Benedict, A. nidulans and A. terreus were sensitive to 0.75R and A. niger, A. fumigatus and A. flavus to the recommended dose of the fungicide. Fungal Strains showed maximum resistance against Wisdom and Primacy as they continue to grow even at recommended doses of these fungicides. Thus the application of fungicides may cause alteration in soil microbial community structures. [ABSTRACT FROM AUTHOR]