1University of Technology and Agriculture, Department of Phytopathology, Kordeckiego 20, 85-225 Bydgoszcz, Poland; 2Kujawiak Brewery, Ustronie 7, 85-161 Bydgoszcz, Poland

Background and objectives
Increasingly, the broadly understood problem of environmental protection and growing consumer interest in so-called 'healthy food' are encouraging many farmers to change their method of land management from an intensive or conventional to an ecological one, thus stimulating research in this area [1]. Ecological agriculture has to imitate phenomena observed in natural ecosystems and ensure that a balance is kept in the state of biocenotic processes in agro-ecosystems. It is considered that pathogens are harmful mainly where balance is disturbed, and also as a result of pesticide applications. Because interest in spring barley production and ecology is still increasing, the purpose of the experiments described here was to determine the influence of farming methods on the health of spring barley cv. Damazy.

Materials and methods
Sown seeds, plants within their vegetative period as well as harvested seeds were the subjects of this investigation. On ecological farms, where cultivation has been carried out for several years in accordance with international standards, their own, non-treated seed material was applied, while on conventional farms seeds were treated with tebuconazol. The percentage of seeds infested by fungi was estimated. Isolation of fungi was carried out by means of standard methods. The health status of plants was estimated at both emerging and ripening stages. The following elements have been taken into consideration: root and culm base diseases (a scale from 1-6), as well as leaf and culm diseases (1-5) and head diseases (1-7) . For this purpose 25 plant samples were collected in four repetitions.

Results and conclusions
From seeds sown on ecological farms, 148 colonies of fungi were isolated: Bipolaris sorokinianawas found on 92% of seeds, Alternaria altemata on 17%, Fusarium spp. on 10%, Epicoccum nigrum on 8%, Cladosporium herbarum on 4%, Aureobasidium pullulans on 2%, and non-sporulating fungi on 15%. From treated seeds for sowing on conventional farms, 76 colonies of fungi were isolated: B. sorokiniana was found on 56% of seeds, A. alternata on 7%, Fusarium spp. on 6%, and non-sporulating fungi on 7%.

From harvested seeds produced on ecological farms, 147 colonies of fungi were isolated: B. sorokiniana was found on 52% of seeds, E. nigrum on 27%, Fusarium spp. on 25%, A. alternata on 24%, C. herbarum on 3%, Penicillium spp. on 1%, and non-sporulating fungi on 15%; from conventional farms, the respective percentages (137 colonies) were 38, 40, 20, 23, 0, 2 and 14%. In emerging plants in ecological farms, the average score of root disease was 2.3 and of culm base disease, 1.7, and 12% of seedlings were diseased by Drechslera teres; on conventional farms the relative values were 1.1, 1.04, and 1%.

At the ripening phase on ecological farms, the average degree of root disease was 1.7, of culm base disease 2.5, and of leaf disease, 3.1, where 27% of leaves were infected by D. teres, 2% by B. sorokiniana and 77% by both these fungi. the degree of leaf disease caused by Rhynchosporium secalis was 1.21, and of head disease caused by B. sorokiniana and Botrytis cinerea, 1. 1. On conventional farms, the relative values were 1.2, 1.6 and 2.5, 13%, 0% and 87%, 1. 1 and 1. On both types of farm, culms were healthy (1). On ecological farms, more pathogenic fungi were isolated from sown seeds and plants were characterized by lower health status. This may have an influence on their use value. The results obtained should be considered as preliminary because there are no other data concerning similar investigations in Poland. However, because of a broad interest of 'healthy food', examination of these problem considers to be necessary. Some of the trends observed here may provide encouragement for further projects which might extend the ecological bases of modern plant protection.

1. Rasmussen IA, Kristensen K, Stetter S, 1995. In Proceeding of a Symposium, Edinburgh, UK, 11-14 September 1995. BCPC, Farnham, pp. 431-438.