Dothistroma<i>needle blight in a New South Wales</i>Pinus radiata<i>plantation in relation to soil types</i>

Abstract

Summary A Pinus radiata plantation on the northern tablelands of New South Wales was surveyed to determine possible relationships between infection by Dothistroma septospora and environmental parameters including soil parent material, slope, aspect, position on slope, depth of soil to impermeable layer, and presence of weed species. Soil parent material appeared to be the main factor influencing the incidence and severity of infection by Dothistroma. The highest average infection occurred on sulphur-deficient basalt parent materials but infection levels appeared to be influenced also by other soil and topographic factors. It is suggested from these patterns and from other experimental evidence from this forest that particular soil parent materials produce stress factors which lead to increases in foliar levels of specific amino acids and that these food sources for the invading fungus enhance its growth rate.