Screening of Tolerance of Plum Cultivars to the Plum Moth Grapholita funebrana (Treitschke)

Plum fruit moth, Grapholita funebrana is one of the most important plum (Prunus domestica) pests. This project was carried from 2019 to 2021 to screen 26 cultivars and promising genotypes of plum in terms of pest larvae feeding tolerance index. The percentage of injury and the larvae population were measured every ten days until the end of October during the activity period of larvae. Then the biological stress sensitivity index was calculated. Time series models were used to investigate the correlation between injury percentage and larval population density, and the cluster analysis method was used to separate cultivars and genotypes based on tolerance index. The degree of influence of different fruit characters on tolerance was investigated by calculating Spearman's correlation coefficient. The results showed that the maximum effective day-larva index in the study years was in late July to early August. The values of cross correlation coefficient in Ghalo and Sosormi cultivars had maximum and minimum values, respectively. Finally, Queen Roza and Anjelo were the most sensitive, and Qomi, Gholaman, Faryar, G-Black, Zojlo, Gallo, G-100, G98, G99, Mortini, Black Amber and Kermanshah were the most tolerant cultivars to plum moth. Fruit surface area, sphericity index, average diameter of fruit engineering, fruit size index, fruit length and width had positive and significant correlation with tolerance indices. The results of this research are part of the breeding program of plum cultivars to develop the cultivation of this product in the country.