Theses and Dissertations Collection

The pale cyst nematode, Globodera pallida, is a highly specialized, economically important pest for potato production. The specialized hatching requirements, ability to adapt, and the loss of effective control strategies such as methyl bromide fumigation increases the challenge to eradicate G. pallida in Idaho. Without a suitable host, this nematode can remain dormant as encysted eggs in soil for up to 20 years. The specificity of G. pallida hatching makes this life stage a potential target for designing efficient integrated control strategies. In this study, first, we demonstrated that Sinapis alba seed meal extract (SME) or 4-hydroxy benzyl alcohol (HBA) under laboratory and greenhouse conditions enhances G. pallida egg hatch when exposed to potato root diffusate (PRD). This hatch enhancement in the presence of PRD is speculated to be due to an increase in egg-shell permeability. This study also aims to determine the efficacy of non-host trap crop Solanum sisymbriifolium or biofumigant Brassica juncea SME to control G. pallida when combined with the hatch enhancement properties of HBA or Sinapis alba SME. For this study, we tested the efficacy of i) S. sisymbriifolium following prior treatment with S. alba SME (0, and 4.48 t/ha) or HBA (0, and 0.12 t/ha) and ii) B. juncea SME (0, 0.14, 0.56, and 1.12 t/ha) following HBA treatment (0, and 4.48 t/ha) on viability and hatch of G. pallida encysted eggs. S. sisymbriifolium alone reduced the number of encysted eggs compared to non-treated control by up to 67%, indicating that this trap crop triggered G. pallida egg hatch. When combined with S. alba SME or HBA, S. sisymbriifolium further significantly reduced egg count, hatch, and viability than S. sisymbriifolium alone. The combination of S. sisymbriifolium with HBA or S. alba SME eliminated G. pallida reproduction on the susceptible potato cultivar, Russet burbank. Treatments with all the tested rates of B. juncea SME alone or with HBA reduced egg hatch and viability compared to the non-treated control. Combining HBA and B. juncea SME further reduced egg hatch and viability than SME alone at rates 0.14, 0.56, and 1.12 t/ha. A lower egg hatch and viability with these combinations indicate that S. alba SME or HBA was able to increase the susceptibility of PCN eggs to the trap crop S. sisymbriifolium or nematicidal effect of B. juncea seed meal extract thus, decreasing G. pallida populations more effectively and rapidly.