EVALUATION OF THE SUSCEPTIBILITY OF PEAR CULTIVARS TO SCAB (VENTURIA PIRINA ADERH.)

Pear (Pyrus communis L.), the second most common pome fruit crop in Latvia, is susceptible to pear scab (caused by Venturia pirina (Aderh.)), the most important fungal diseases in Latvia, that can significantly decrease yields and fruit quality. Therefore, the aim of this study was to evaluate the differences of pear scab severity on fruits among pear cultivars grown in Latvia. The study was performed at the Latvia State Institute of Fruit-Growing on 37 pear cultivars. The severity of pear scab was assessed in natural conditions of infection, with the same fungicide treatment as in commercial orchards, uniformly applied to all cultivars. The severity of pear scab on fruits among cultivars was evaluated for six years at harvest. Pear scab severity varied among cultivars as well as among the years of evaluation. The severity of disease increased during more humid growth periods with moderate temperature. There were no completely resistant cultivars among the tested ones, and only a variability of susceptibility was observed. The highest resistance was stated for cultivar ‘Shchedraya’, high resistance was also found for cultivars ‘Conference’, ‘Concorde’, ‘Eckehard’, ‘Osennyaya Grusha’, ‘Tayushchaya’, ‘Talgarskaya Krasavitsa’ and ‘Vizhnitsa’, whereas the highest susceptibility was found for cultivars ‘Beta’, ‘Fritjof’, ‘Jubileen Dar’ and ‘Rescue’. Other tested cultivars showed moderate susceptibility of pear scab on fruits.