Control of Globodera pallida using Sinapis alba or 4-hydroxy benzyl alcohol with the trap crop Solanum sisymbriifolium or the biofumigant Brassica juncea seed meal extract

Abstract

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 increase 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. 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. We then tested the efficacy of i) Solanum sisymbriifolium following prior treatment with S. alba SME (0, and 4.48 t/ha) or HBA (0, and 0.12 t/ha) and ii) Brassica juncea SME (0, 0.14, 0.56, and 1.12 t/ha) following HBA treatment (0, and 4.48 t/ha) on egg viability, hatch and reproduction of G. pallida encysted eggs. Solanum 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 significantly reduced egg count, hatch, and viability more than S. sisymbriifolium alone. The combination of S. sisymbriifolium with HBA or S. alba SME eliminated G. pallida reproduction on the susceptible potato. All the tested rates of B. juncea SME alone or with HBA reduced egg hatch, viability and reproduction compared to the non-treated control. Combining HBA and B. juncea SME further significantly reduced egg hatch, viability, and reproduction than those rates of B. juncea SME alone.