Selective effects of five pesticides on soil and cotton-rhizosphere and-rhizoplane fungus flora

In two field sowings, the effect of five pesticides on soil, rhizosphere and rhizoplane fungi was tested. Ceresan and Orthocid (fungicides used as seed dressing) after 3 days were very toxic to the total count of soil fungi and to almost all fungal genera and species. After 40 days their toxicity was almost alleviated in the soil, but persisted in the rhizosphere. The herbicide VCS 438 did not significantly affect the total count of soil fungi but was initiative to the total rhizosphere fungi. Some fungal species were significantly promoted in the soil and rhizosphere and others were depressed. Dipterex (Insecticide) was promotive to the total count of soil fungi after 3 days and to some fungal species but this effect was almost alleviated after 40 days. In the rhizosphere, it exerted a promotive effect on the total count of fungi and on some fungal genera and species. Dursban (Insecticide) was of no significant effect on the total count of soil and rhizosphere fungi, but few species were significantly promoted.The rhizoplane fungi were the least sensitive, and none of the five pesticides induced a significant effect on the total count, but some species responded significantly, being either promoted or inhibited.