SOME ASPECTS OF THE BIOLOGY OFDIPLODIA PINEAIN RELATION TO ITS CONTROL BY FUNGICIDES

Abstract

Studies of the rates of mycelial growth and spore germination at different temperatures as well as the sensitivity to fungicides of Diplodia pinea were undertaken to investigate the possibility of controlling its invasion of haildamaged pine trees by aerial spraying or dusting with fungicides. Pycnospores were found to be capable of rapid germination and mycelium of rapid growth over a wide range of temperatures. Maneb and cycloheximide were found to inhibit mycelial growth on potato-dextrose agar at one-eighth of the concentration, or less, of copper-based fungicides. Weather conditions and other considerations may, however, result in postponement of application of the fungicides so that cycloheximide may prove to be the only fungicide of any practical value. Further investigation of the use of cycloheximide against D. pinea is, however, required.