Thein vitro effect of some pesticides on the nitrogen fixing bacteria isolated from the phyllosphere of some crop plants

Summary Thein vitro effects of twelve commonly used pesticides, including the fungicides Cuman-L (Ziram) and Hinosan (Ediphenphos), the acaricides Nuvacron (Monocrotophos), Ekatin 25EC (Thiometon) and Ekalux-G₅ (Quinalphos) and other insecticides namely Dimecron (Phosphamidon), Anthio 25EC (Formothion), Baytex (Fenthion), Metasystox (Methyl demeton) and Phosalone (Zolone), on the nitrogen fixing bacteria isolated from the phyllosphere of some crop plants were tested. A very wide variation of the effect of these pesticides on the different organisms was noted. At a concentration of 700 g/ml in the medium, most of the pesticides completely inhibited growth of the nitrogen fixing bacterial isolates. However, with some pesticides, when used at a lower concentration, a degree of growth stimulation was recorded.