Species of Alternaria on Brassica Hosts in New Zealand

Abstract

Isolants typical of A/ternaria brassicae (Berk.) Sacc., A. brassicico/a (Schw.) Wiltshire, A. lenuis Auct. and A. Ienuissima (Fr.) Wiltshire have commonly been obtained from Brassica hosts in New Zealand. Inoculation into a range of host plants shows that A. brassicae and A. brassicico/a are pathogens of cruClferous hosts, primarily Brassica spp. A. tenuis and A. tenuissima may be strictly saprophytic, or capable of producing restricted lesions on damaged tissue of a wide range of hosts. In the experimental work, the formation of short beaks in A. tenuissima, and the formation of long beaks in A. tenuis isolants grown on damaged tissue at low temperature and humidity, indicate that the morphological characters used to differentiate the two species are in fact variations of one species caused by changes in environment. © 1964, Taylor & Francis Group, LLC. All rights reserved.