Crop Rotation with Resistant Potato and Solanum sisymbriifolium to Control Globodera pallida

Globodera pallida, the pale cyst nematode is a regulated pest in Idaho. This study investigated whether rotation of the trap crop Solanum sisymbriifolium and a resistant potato variety was effective for controlling G. pallida in Idaho. The highly resistant potato variety, 'Innovator', was used. Three-year crop rotations incorporating 'Innovator' and S. sisymbriifolium before a susceptible potato were established in an Idaho field. At the end of each growing season, the impact of each crop on the initial population used to infest soil and progeny cysts was evaluated. 'Innovator' and S. sisymbriifolium similarly reduced encysted eggs of the initial population by 70% after the first year. However, S. sisymbriifolium further reduced egg viability of the initial population to 58%, compared with 'Innovator' plots with 89% egg viability. By the end of year 3, reproduction factors (RF; final egg population/initial egg population) showed that all rotations resulted in 99%-100% overall reduction in the initial G. pallida population density. After 2 years of S. sisymbriifolium, cysts were undetectable following the susceptible potato 'Russet Burbank'. These results demonstrate the potential of S. sisymbriifolium and resistant potato in rotation to reduce G. pallida population densities.