Susceptibility of collection pear cultivars to the agent of scab pathogen Venturia pirina Aderh

The objective of the research is to study the biology of the pathogen of the scab Venturia pirina Aderh depending on the agrometeorological conditions of the pear vegetation and to assess the collection cultivars for susceptibility to the disease. The biological features of the pear scab in the western foothill agro-climatic region of the Crimea are studied. The influence of climatic conditions on the occurrence of various epidemiological types of scab manifestations on pears is estimated. As a result of the research, highly resistant cultivars were found: Zhukovka, Zaporozhskaya, Triumph of Jodoin, Vodyanistaya, Dorodnaya, Bere Shibasso, Martin Sekl, which showed moderate levels of infection spread in all years of research, with the development of the disease in the range of 0.2-1.3%. Immune cultivars of pears with absolute resistance to the pathogen agent V. pirina, which was not affected by changes in weather conditions, were identified. These cultivars are the following: Zimovka, Trapezitsa, Chervona, Shara Bera, Seyanets Kolossa, Populyarnaya, Kurzemskaya Maslyanaya, Wonderful Italy, which can be used in breeding and ecologized protection systems when supplying with cuttings horticultural industries in the Crimea and the south of Russia.

New perspective pear (Pirus communis L.) cultivars bred at the Institute of Horticulture, NAAS of Ukraine

The authors present the results of researching pear new elite forms and cultivars bred at the Institute of Horticulture of the National Academy of Agrarian Sciences, namely: Vezha Muskatna, Dekanka Muskatna, Kytaisky Likhtaryk and hybrid 17-103 with the hight productivity potential – the yield of five year trees on the rootstock IS 4-12 was 40 kg/tree (45 t/ha) under the planting plan 5x2 m. The beginning of the fruit-bearing was early – in the third-fourth years after planting on the mentioned rootstock. The investigated cvs and forms are s.cab (Venturia pirina) resistant, Kytaisky Likhtaryk and Dekanka Muskatna high bacteriosis (Pseudomonas syrnigae) tolerant. The fruits are substantially attractive and characterized with high marketable (Kytaisky Likhtaryk, Dekanka Muskatna), taste qualities (Vezha Muskatna, 17-103) and the refrigerator under the temperature 2 0C. The explored forms and varieties are favourable for the creation of intense trellisless energy-saving ecological orchards with the dwarfing intercalary Pirognom as well as in the breeding work as the sources of concrete signs valuable for economy, namely: early-riping, high yield, resistance to fungous diseases and bacterioses, high taste and marketable qualities, pulp ocliness. The researches have also showed that the high marketable and taste qualities of the created cultivars under moderate sums of the effective temperatures (2500-2700 0C) during the vegetation period make it possible to promote to the Northern regions of Ukraine the cultivation of this valuable crop in industrial and amateur orchards.

Measures to Prevent and Combat Pear Scab (Venturia pirina) in the Climate Conditions of Lapusel

In this paper we studied the emergence and development of pear scab (Venturia pirina), as well as the combat methods, testing a couple of fungicides. The aim of the research has been to highlight the resistance, respectively the sensitivity of some pear varieties against the fungi attack, in order to make recommendations for the new plantations, as well as the testing of 7 fungicides, remarking the product with the highest biological effectiveness. The researches were conducted in the years 2013-2014 at the company SC Mecanochim Lapusel, Maramures County. The experiments were conducted on plots planted with the Olivier de Serres and Bergamotte Crassane varieties. The attack was calculated determining the attack frequency, intensity and degree. The linear-interrupted method was used, comprising 3 variants of 5 trees each. Analyzing the climate data, it has resulted that in 2013 scab had favourable development and attack conditions. The Olivier de Serres variety was noted for its resistance to fungus attack, with a frequency of 0.2-1.3% on fruits and insignificant frequency on leaves, for all 7 tested product variants. The Bergamotte Crassane variety was placed on the other end, with a higher frequency and intensity, both on fruits (2-3%) and on leaves (2.5-3.5%). The infections diminished in 2014 due to the unfavourable climatic conditions. Three products had better results, from the seven tested products, thus: Alcupral 50PU, Stroby DF and Chorus 50 WG.

Susceptibility of European pear cultivars to Venturia pirina Aderh. infection at a variety collection in Hungary

Field sensitivity of 271 European pear genotypes were evaluated in a large variety collection of pear in Hungary during a nine years survey. Substantial differences were detected in the rate of pear scab infection of leaves and fruits. Some 18 per cent of the inspected genotypes remained completely free of infection even in the years with weather favouring to the disease. On the other hand, 78 % of the inspected genotypes were infected in some or more extent. The rate of infection was generally higher on leaves than on fruits. 18.6 % of the genotypes inspected were tolerant to leaf infection and their majority (81.1 %) were tolerant to fruit infection. Some one fi fth of the genotypes (19.7 %) were highly susceptible to leaf infection but only minor rate of them (2.2 %) were highly susceptible to fruit infection. There were 44 genotypes that could be regarded as tolerant to pear scab leaf and fruit infection under fi eld conditions. Some of these genotypes may be suitable to commercial pear growing with highly reduced chemical control against pear but their yield capacity and fruit quality should be evaluated.