A study of two seed-borne Alternaria diseases on choumoellier : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University

Abstract

The livestock industry in New Zealand is based on a pastoral farming economy, an important aspect of which is the utilisation of fodder crops as supplementary feed during seasons of poor pasture growth. Playing an important role in this regard are the two selections of choumoellier (Brassica oleracea var. acephala D.C.) usually referred to as giant choumoellier and medium stemmed choumoellier. The growing importance of choumoellier in feed crop rotations is indicated by the increased area sown, from 8,000 acres in 1933 to 130,000 acres in 1963 (New Zealand Farm Production Statistics, 1962-63). In the past, choumoellier seed has been imported from the United Kingdom, but more recently the trend has been to promote locally grown seed. At the present time New Zealand's requirements are met in most years by South Island growers producing seed under the authority of a Government seed certification scheme. In discussing brassica crops in New Zealand, Palmer (1966) stated that - "apart from weather variations, the main

uncontrollable causes of yield variations are fungus diseases, insect pests and associated virus diseases''• Seven fungus

diseases are recorded in

New Zealand on choumoellier (Table 1),

five of which are evidenced by foliage lesioning in field stands.