Differential beet leafhopper (Hemiptera: Cicadellidae) acceptance of barley (Poales: Poaceae) and brown mustard (Brassicales: Brassicaceae) cover crops

Chile pepper, Capsicum annuum L. (Solanales: Solanaceae) yield in New Mexico is threatened by a multitude of factors, including beet curly top virus (BCTV) vectored by the beet leafhopper, Neoaliturus tenellus (Baker), and competition with annual weeds. Early-season weeds in chile pepper can be reduced by either barley, Hordeum vulgare L. or brown mustard, Brassica juncea (L.) Czern. cover crops; however, the potential of attracting N. tenellus should be factored into cover crop selection. In this study, dual choice tests were carried out between a brown mustard cultivar ('Caliente Rojo') and two barley cultivars ('Stockford' and 'Valor'). In a subsequent no-choice test, viruliferous N. tenellus were caged onto individual leaves of barley and brown mustard, and plant tissue was stained and examined for the presence of sheaths, punctures, and eggs. N. tenellus demonstrated a nine times greater acceptance of brown mustard than either barley cultivar. In no-choice tests, viruliferous N. tenellus successfully produced sheaths on brown mustard four times more than N. tenellus trapped on barley. N. tenellus survival was lower on Stockford barley than both Valor barley and brown mustard. No eggs were laid on either barley cultivar, indicating its unsuitability as an oviposition host. This research indicates that barley is less likely than brown mustard to sustain N. tenellus populations with the capacity to transmit BCTV to subsequently planted chile pepper. Accordingly, farmers attempting to manage early season chile pepper weeds with cover crops, while minimizing potential habitat for N. tenellus, should select barley rather than brown mustard.