Effect of virus infection on growth and cropping of Greengage and Billington plum trees

Abstract

In a trial with Greengage European plum (Prunus domestica L.) grown over a 20-year period, an analysis of the final 15 years showed that there was no significant difference in growth rate between trees infected with plum line pattern, apple chlorotic leaf spot, and Prunus necrotic ringspot viruses, and trees infected with Prunus necrotic ringspot virus alone. However, over 8 years of cropping, the overall loss of yield as a result of virus infection was 20%. In another trial with Billington Japanese plum (P. salicina Lindl.), trees free from virus infection were compared with trees infected with a single virus or with several viruses in combination. Over a 9-year period, the rate of growth was adversely affected only in trees infected with the line pattern strain of plum line pattern virus in combination with Prunus necrotic ringspot and apple chlorotic leaf spot viruses. Over a 5-year cropping period, either of 2 strains of plum line pattern virus combined with Prunus necrotic ring-spot and apple chlorotic leaf spot viruses significantly reduced yield. When trees were infected singly with either Prunus necrotic ringspot or apple chlorotic leaf spot, or with a combination of Prunus necrotic ringspot and prune dwarf viruses, yields were not affected.

Keywords:

• Prunus domestica
• Prunus salicina
• plums
• plant viruses
• growth rates
• yield losses