Leaf Characteristics of Eucalyptus Bicostata Maiden Et Al. Seedlings Affecting the Deposition and Germination of Spores of Phaeoseptoria Eucalypti (Hansf.) Walker

The water·soluble fraction of the ether·soluble moiety of the glaucous coating on the juvenile leaves of seedlings of Eucalyptus bicostata Maiden et al. inhibited the in vitro germination of the conidia of Phaeoseptoria eucalypti (Hansf.) Walker. A negative correlation was obtained between susceptibility of leaves to P. eucalypti leaf spot and the weight per unit leaf area of ether-soluble substances also soluble in water. Glaucousness of seedling leaves and inhibition of spore germination both increased acropetally, glaucousness also increasing when seedlings were raised at lower temperatures. The glaucous coating of leaves was strongly hydrophobic and affected the deposition of conidia from water suspensions as did the leaf angle.