SUPERIORITY OF SILVER NITRATE OVER MERCURIC CHLORIDE FOR SURFACE STERILIZATION IN THE ISOLATION OF OPHIOBOLUS GRAMINIS SACC.

Abstract

It has been difficult to isolate Ophiobolus graminis from plant parts previously surface sterilized by the commonly used mercuric chloride method, although Helminthosporium sativum and Fusarium spp. are readily isolated following its use. When a silver nitrate method of surface sterilization was substituted, O. graminis was isolated with considerably more success than had previously been obtained. These results can be explained by the difference in reaction of the above-mentioned fungi to these chemicals. When similar concentrations of these chemicals were added to nutrient agar, silver nitrate proved less toxic to O. graminis than mercuric chloride, whereas the reverse was true for H. sativum.