NECTRIA VRSTE U ŠUMAMA BUKVE NA PODRUČJU PRNJAVORA

Rasprostranjenje bukve, tehnička, privredna ali i opšte korisna važnost ove vrste drveta u šumamaRepublike Srpske nameće potrebu kontinuiranog praćenja njenog zdravstvenog stanja. Posebnovelike štete u sastojinama bukve prouzrokuju Nectria vrste. Na području našeg istraživanja konstatovanesu sledeće vrste iz roda Nectria: Nectria coccinea (Pers. ex Fr.) Fries, Nectria ditissima Tul.,Nectria galligena Bresad. Parazitne gljive iz roda Nectria zajedno sa insektom Cryptococcus fagisugaLind. izazivaju bolest pod nazivom „bolest kore bukve“. U većini slučajeva „bolest kore bukve“ jeuzročnik propadanja bukovih stabala.

The use of composition of carbendazim and captafol in control of diseases of apple tree

The composition of two fungicides: carbendazim 40% and captafol 40% gave very good to fair control of apple tree diseases. This formulation was used in field experiments against apple scab, bark canker fungi and bitter rot of apple fruits. The 0,06 per cent concentration was very effective against strains of <em>Venturia inaequnlis</em> tolerant and resistant to benzimidazole fungicides. The 0,1 per cent concentration gave very good control of <em>Nectria galligena</em> and <em>Pezicula malicorticis</em> and fair control of <em>Stereum purpureum</em> and <em>Phvtophthora cactorum</em>.

Susceptibility of apple cultivars to bark canker diseases

The susceptibility of 26 apple cultivars to four bark parasites: <i>Nectria galligena, Pezicula malicorticis, Stereum purpureum</i> and <i>Phytophthora cactorum</i> was investigated. A close correlation was found between indices of susceptibility to the fungi <i>N. galligena, P. malicorticis</i> and <i>S. purpureum</i> and no correlation between the indices of susceptibility to <i>P. cactorum</i> and the three remaining pathogens. Five groups of susceptibility to the complex of bark canker fungi were distinguished, oomprising three or four species of fungi. Highly susceptible cultivars: 'Delikates', 'Melrose', 'Spartan', 'Prima' and 'Slava Pobeditelam'. Rather susceptible cultivars: 'Starkrimson', 'Hibernal', 'Florina', 'Priscilla', 'Priam', 'Macfree' and 'NY 55-158-2'. Moderately susceptible cultivars: 'Macoun', 'Liberty', 'NY 55-140-9', 'Vista Bella', 'Jerseymac' and 'Šampion', Little susceptible cultivars: 'Discovery', 'Empire', 'Fantazja' and 'Primula', But slightly susceptible cultivars: 'Golden Delicious', 'Idared' and 'NY 58-533-1'.

Actual status of the beech bark necrotic disease in NorthWestern Bulgaria

In this paper we present recent findings about the beech bark necrotic disease in selected localities situated in the mountain ranges Vitosha and Stara planina in Bulgaria. The resulting values of necrotic disease expressed by the necrotisation index (I_SN) ranged from 0.72 to 1.12. In Slovakia such low values of I_SN were obtained only for seven out of 52 examined localities. The I_SN results are more favourable than the results obtained using the same methods for four localities situated in Northern Hungary (I_SN values ranging from 1.11 to 1.18). The results of monitoring of three selected biotic vectors of beech necrotic disease were follows: the focus of occurrence of the species Bucculatrix ulmella was in submountain beech forests. Considerable affinity to lower situated sites was found in Ectoedemia liebwerdella. We also found that the boundary of the occurrence of this species is approximately at 1,000 m a.s.l. The frequency values of Cryptococcus fagi were significantly influenced by the altitude. In four out of six localities we recorded the occurrence of three species of the genus Nectria: Nectria cosmariospora, Nectria galligena and Nectria coccinea.

PATHOLOGICAL ANATOMY OF NECTRIA CANKER ON FRAXINUS MANDSHURICA VAR. JAPONICA

The anatomical characteristics of Nectria canker on Fraxinus mandshurica var. japonica were analyzed. Typical cankers were conspicuous, round to oval, with uniform concentric rings of affected xylem in a target-like structure. Each concentric annual growth ring was wider than the corresponding annual rings lateral to the cankers. The xylem elements were extremely disoriented. The cambial zone became discontinuous and disappeared. An inoculation test with the causal fungus, Nectria galligena, produced similar anatomical abnormalities and revealed the process of canker formation. Fewer and narrower vessels were formed, and water conduction took place only in the large vessels of the current year in the cankers.