Physiological Studies of Some Fungi Associated with Pole Blight of Western White Pine

Abstract

Four isolates of Leptographium sp. and one of Ceratocystis pilifera obtained from pole blighted trees were tested in vitro to determine certain of their physiological requirements. Optimum temperatures for the Leptographium isolates ranged from 15[degree] to 25[degree]C. C. pilifera grew best at 25[degree]C. The optimal pH for all test organisms was approximately pH 6.0. Vitamin deficiencies varied for the five fungi. All required biotin for growth. Pyridoxine is required by C. pilifera and thiamine by one isolate of Leptographium. A partial thiamine deficiency in another Leptographium and partial deficiencies of both pyridoxine in the third Leptographium were observed. With the exception of biotin, the fourth Leptographium had no deficiencies. Utilization experiments with 15 carbohydrate and 25 nitrogen compounds indicate some diversity in the capabilities of the organisms to use the various compounds for growth. The Leptographium isolates apparently have somewhat similar enzymatic potentials but differ in this respect from C. pilifera. It was concluded that differentiation between the isolate of C. pilifera and the Leptographium isolates used in this study may be possible, based on their respective abilities to use certain carbon or nitrogen compounds. This basis would not appear to be of practical use in distinguishing between isolates of Leptographium; however, certain trends for diffentiation were observed and would merit further testing.