Jelica Balaz

Occurrence of Xanthomonas campestris pv. campestris (Pammel, 1895) Dowson 1939, on brassicas in Montenegro.

Brassicas form the most important group of vegetable crops in Montenegro. The cabbage (Brassica oleracea var. capitata) is most commonly grown, although other brassicas, particularly kale, Brussels sprout, cauliflower and broccoli, have been increasingly produced since recently. One of the specialties of vegetable production in Montenegro is growing of collard (Brassica oleracea var. acephala), which is the simplest variety of the Brassica oleracea species and in the nearest relation with their wild ancestor - the sylvestris variety. Diseases are the main restrictive factors for successful production of these vegetables. Susceptibility of the cultivars and inadequate control often result in more or less damaged crops in some plots. Causal agents of brassica diseases, especially bacterial, have not been investigated in Montenegro until 2009. Since the symptoms observed in 2009 were „V” shaped leaf edge necrosis and black rot of vascular tissue, it was assumed that they were caused by plant pathogenic bacterium Xanthomonas campestris pv. campestris. Samples of the infected plants were collected from different localities in Montenegro. Isolation and identification of the bacterium were performed using laboratory methods according to Schaad (1980), Lelliott and Stead (1987) and Arsenijevic (1997). Examination of chosen bacterial isolates was conducted using both, classical bacteriological methods (examination of their pathogenic, morphological, cultivation and biochemical and physiological characteristics), and ELISA test. The obtained results confirmed the presence of X.campestris pv. campestris (Pammel, 1895) Dowson 1939, on cabbage, kale, broccoli and collard in Montenegro. This is the first experimental evidence that collard is the host of X. campestris pv. campestris in Montenegro.

Evaluation of possibilities of Venturia inaequlis control by ecologically acceptable products.

Possibility of V. inaequalis control on apple variety Idared was evaluated by ecologically acceptable products such as inorganic fungicides and acidified clays. The obtained results were compared with common, chemical protection. Year 2009 was one of the unfavorable for V. inaequalis, and 2010 was extremely favorable for apple scab development. Accordingly, in 2009 intensity of infection on apple leaves and fruits in control variant was low (leaves 15,4-34,9%; fruits 0-23,8%). In 2010 infection intensity on leaves and fruits was high (leaves 81,2%; fruits 100%). During period 2009-2010, in these different environmental conditions, common chemical protection showed high efficacy (leaves 96,2-100%; fruits 97,5-100%). High efficacy level in control of V. inaequalis on leaves of 87,4-99,7% was achieved also in variants in which copper products were applied in low concentration of 0,05%. It should be noted that in the most critical period, in April and May of 2010, the treatments were carried out in 5-6 days interval. Copper products showed differing efficacy on fruits (48,5-90,2%). In 2009 which is considered as one of the unfavorable for V. inaequalis development, product Ulmasud B applied alone on leaves was less efficiacy (51,8-58,6%), than on fruits (87,8%). In the same year, efficacy of this product in combination with sulfur, was better (leaves 71,4-76,6%; fruits 86,6). In 2010, which was especially rainy and favourable for spreading the disease, efficiacy of mention combination of products didn,t satisfy (leaves 44,8%; fruits 41,0%). In the system of organic production, during vegetation period, program of apple protection in control of V. inaequalis should be supplemented by use of low concentrations of copper products (0,05%) and by various alternative products of different action mechanisms, such as mineral clays, sulfur products and etc. These researches should be continued.

The Status of Erwinia amylovora in the Former Yugoslav Republics over the Past Two Decades

SUMMARY Erwinia amylovora, the causal agent of fire blight (FB) on fruit trees and ornamental plants, rapidly spread across eastern Mediterranean countries in the early 1980s. This quarantine bacterium probably arrived in the southern parts of the former Yugoslavia (now FYR Macedonia) from Greece. Based on symptoms, and isolation and identification data, it was concluded that Erwinia amylovora was the causal agent of pear drying in Macedonia (1989). It was the first experimental confirmation of a presence of E. amylovora in the territory of the former Yugoslavia. The presence of E. amylovora was also proved in Serbia that same year. In Bosnia and Herzegovina, FB was detected during 1990. Based on an official report filed with the Federal Ministry of Agriculture in Belgrade, the presence of E. amylovora in Yugoslavia was confirmed (EPPO – Reporting Service, 1991). Therefore, the presence of the bacterium E. amylovora in the territory of Yugoslavia was officially confirmed in 1990. In Croatia, FB was first observed in villages near the border on Serbia in 1995. In Montenegro, FB was first detected in 1996. In Slovenia, FB appeared as late as in 2001. E. amylovora is now present on 10 hosts (pear, wild pear, apple, quince, medlar, mountainash, hawthorn, firethorn, cotoneaster and Japanese quince) in the territory of the former Yugoslav republics. Based on literature data, losses caused by FB in the former Yugoslav republics in the period 1989-1992 were estimated at about 12,000,000 DEM (mostly in Macedonia) and in the period 1992–1996 at 6,000,000 DEM. Total damage in a more recent epiphytotic year in Slovenia (2003) was estimated at