Impact of Globodera ellingtonae on yield of potato (Solanum tuberosum).

Abstract

Globodera ellingtonae was described from Oregon and Idaho in 2012. Due to the close phylogenetic relationship of this nematode to the potato cyst nematodes G. pallida and G. rostochiensis, and evidence that G. ellingtonae reproduces on potato (Solanum tuberosum), potential damaging effects to potato by this nematode are of great concern. To evaluate the pathogenic effects of G. ellingtonae on potato, five field and two microplot trials were conducted over a four-year period including comparisons of a range of G. ellingtonae initial population densities (Pi) and potato cultivars. In two field trials, potato ‘Russet Burbank’ was inoculated with Pi of G. ellingtonae ranging from 0 to 80 eggs/g soil; a similar trial was conducted with potato ‘Désirée.’ In another field trial, potato cultivars varying in maturity lengths were either inoculated (80 eggs/g soil) or not with G. ellingtonae. In a final field trial, ‘Ranger Russet’ was inoculated with Pi of G. ellingtonae ranging from 0 to 360 eggs/g soil. Additionally, Russet Burbank was inoculated with G. ellingtonae Pi ranging from 0 to 169 eggs/g soil in microplots. In all trials, data on tuber yield, aboveground biomass, final eggs/cyst, final population densities (Pf), and reproduction factor (RF = Pf/Pi) were collected. In only two of six trials conducted with increasing levels of Pi, was there a significant negative correlation between Pi of G. ellingtonae and yield of potato. Based on the linear regression model of tuber yield on logPi for Russet Burbank, 30.5 to 40.9% yield loss was predicted at a Pi of 40 and 80 eggs/g soil, respectively, and for Ranger Russet, 16.5 and 19.7% yield loss was predicted at a Pi of 40 and 80 eggs/g soil, respectively. None of the potato cultivars inoculated with 80 G. ellingtonae eggs/g soil had significantly reduced yields compared to non-inoculated plants. Reproduction factor values across trials ranged from 4.0 to 8.3 when inoculated with Pi of 40 eggs/g soil, demonstrating that the nematode successfully invaded and reproduced on potato in all trials. Care should be taken in extrapolating the results from these experiments conducted in Oregon to probable effects of G. ellingtonae on potato in other environments.KeywordsPotato, Damage, Globodera, Regression