2019 ASHS Annual Conference

The thrips-vectored orthotospovirus, Impatiens necrotic spot virus (INSV), causes economic damage due to spotted wilt disease on lettuce in coastal California. Initial symptoms appear as small brown lesions or spots that expand into larger necrotic sections on infected leaves. Stunted, necrotic, or otherwise symptomatic plants are not marketable; high disease incidence results, therefore, in substantial economic losses to growers. The wide range of host species that can be infected by INSV complicates disease control. Therefore, the best strategy for control is the use of INSV-resistant cultivars. In an effort to develop such resistant lettuce germplasm, our objective was to evaluate the progeny of all possible crosses between plants previously identified as partially resistant or susceptible to INSV. Results of preliminary screenings are presented.