Reaction of some nectarine cultivars to Stigmina carpophila (Lev.) Ellis

Veselin Arnaudov, Dimitar Vassilev

Abstract: The response of 8 nectarine cultivars to the attack of Stigmina carpophila (Lév.) Ellis, the pathogen causing shot hole disease (Clasterosporiosis) on stone fruits. The study was conducted in natural conditions of infection, in an experimental orchard at the Research Station of Agriculture – Khan Krum, during the period 2011–2013. Тhe following nectarine cultivars were observed: ‘Aurelio Grand’, ‘Sun Free’, ‘Big Top’, ‘Gergana’, ‘Weinberger’, ‘Nectagrand 2’, ‘Independence’, ‘Caldesi 2000’, all engrafted of the seed rootstock (‘Elberta’) and GF 677 clonal rootstock. The experiments were set in three replicates for each cultivar/rootstock combination. 200 leaves per cultivar/rootstock combination were collected on a random principle from 6 trees (replicates) to detect the level of S. carpophila infection. Symptoms on the leaves were visually determined, and leaves with symptoms depending on the severity of the attack, distributed on a five grade scale. The infectious index was calculated by means of the McKinney (1923) formula. The sensitivity of the cultivars was estimated according to the calculated infectious index. The results show that none of the studied nectarine varieties showed complete resistance to S. carpophila. The cultivars tested were slightly to moderately susceptible and their susceptibility depends on the type of rootstock.

Keywords: cultivars; nectarine; rootstocks; Stigmina carpophila; susceptibility

Date published: 2020-08-13