Assessment of the importance of seed cutting, in-season cultivation, and the passage of row equipment in the spread of PVY° in potatoes

Abstract

Grower concerns, coupled with recent reports, have suggested that potato virus Y° (PVY°) may be spread as the result of mechanical transmission following the cutting of infected tubers during seed multiplication, or through vine abrasion caused by the passage of row equipment used during spraying operations and post-emergence tillage. We present the results of a series of greenhouse and field experiments (on the potato cultivars ‘Shepody’, ‘Russet Norkotah’, ‘Russet Burbank’, ‘Jemseg’, ‘Kennebec’, and ‘Superior’) to examine this possibility. Our results provide no evidence to support the view that mechanical transmission of PVY° occurs through the use of (hand or mechanical) cutting knives. Statistical analysis of the spatial pattern of in-field virus spread in the highly susceptible cultivar ‘Shepody’ did not show a significant clumping of infected plants within plot rows, arguing, in this case, that the passage of farm equipment and associated tillage operations are of no practical significance in the epidemiology of PVY° under growing conditions currently found in the Maritime provinces.