European pear scab (Venturia pyrina Aderh.) is common and economically important disease in commercial orchards in most of the pear (Pyrus communis L.) growing areas worldwide. Studies on pear scab pathogen V. pyrina diversity in general and among different geographical regions are scars at an early stage. In the limited number of studies reported so far, some attempts have been made to characterize and define races or biotypes of V. pyrina and new biotypes co-adapteted to specific cultivars have been recorded recently. Despite the long history, worldwide distribution and increasing economic significance of the European pear scab, the research on control methods, and pathogen biology and disease epidemiology that could aid to develop more effective and also alternative to fungicide application control methods are still limited. Mechanisms of European pear resistance to scab remains uncertain and currently only one major resistance gene Rvp1 has been identified and characterised. Although the disease is important in many European countries, breeding programs of pear scab-resistant varieties are still under development. In this paper we provide an overview on V. pyrina, its significance and distribution, control methods and current scientific progress in understanding of the pathogen and the disease. Overview of literature on V. pyrina characterization, ecology, biology and diseases epidemiology from Latvia and other countries has been used for the study.

Several fungicide applications are used to control a pear scab (Venturia pirina Aderh.) on pear (Pyrus communis L.) trees. Minimal chemicals use in fruit-growing constantly has been important condition in the integrated fruit production; therefore, sanitation is recommended to reduce a primary inoculum in orchards. The study was carried out in an integrated pear orchard located in Sigulda district, in the central part of Latvia to estimate if a fall treatment of a pear orchard with urea reduces an amount of pseudothecia and pear scab incidence level the following season. Six treatments trial was arranged in the autumn 2011 on a moderately susceptible pear cultivar ‘Belorusskaya Pozdnaya’. An amount of leaf litter, pseudothecia and incidence level of a disease on leaves and fruits were determined. The results showed that urea application reduced both an amount of leaf litter and a number of pseudothecia. An average amount of leaf litter was 127 leaves per 0.25 square m in a control and 89 leaves in a treatment with urea application. The number of pseudothecia reached 250 pseudothecia per one leaf disc in a control and 160 pseudothecia in a treatment with the urea application, the difference was not significant (p is greater than 0.05). The reduction of disease incidence level on leaves was significant (p is less than 0.05) only in the first assessment of five in total.