Occurence of Fusarium species isolated from winter wheat and barley grains in Croatia

Fusarium head blight of small grain cereals is an important disease occuring across a broad range of environmental conditions. Several Fusarium species may be associated with the disease, including species that are potentially toxigenic. During the harvest, shrivled infected grains that are light enough to be eliminated from the combine harvester cause direct yield loss. The grains that are less severely infected are lighter that uninfected grains and affect the « ; thousand kernel weight» ; . The objectives of our study were to estimate occurence of Fusarium species on wheat and barley grains and evaluate the influence of Fusarium species on yield and thousand kernel weight. A total of 1352 winter wheat samples and 494 barley samples were collected and analyzed from 1998 to 2005. Eight Fusarium species were isolated from wheat grains and seven from barley grains. The most frequent species on wheat and barley grains was F. graminearum Schw. (52.66% and 39.87% respectively). According to its occurence on wheat grains, F. graminearum was followed by F. moniliforme Sheld. (16.35%), F. subglutinans (Wollenw. & Reink.) Nelson, Toussoun & Marasas (13.68%), F. avenaceum (Fr.) Sacc. (6.88%), F. culmorum (W.G. Smith) Sacc. (3.85%), F. poae (Peck) Wollenw. (3.40%), F. sporotrichioides Sherb. (2.00%) and F. oxysporum Schlecht emend. Snyd. & Hans. (1.18%). On barley grains except F. graminearum the following Fusarium species were isolated: F. moniliforme (16.35%), F. subglutinans (17.00%), F. avenaceum (11.34%), F. poae (4.25%), F. oxysporum (3.85%) and F. sporotrichioides (3.04%). Isolates of F. graminearum were the most pathogenic to wheat and barley grains. Depending on isolates, percentage of infected seeds was between 63.50 and 87.75%. Out of a total of infected seeds, only 30.05 to 49.77% germinated. Weight of 1000 seeds was reduced from 35.05 to 55.00%, if compared to control.