Differential beet leafhopper (<em>Neoalitarsus tenellus</em> (Hemiptera: Cicadellidae)) acceptance of allelopathic barley (<em>Hordeum vulgare</em> (Poales: Poaceae) and brown mustard (<em>Brassica juncea</em> (Brassicales: Brassicacae) cover crops

<p>Chile pepper, <em>Capsicum annuum</em> 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, <em>Neoalitarsus tenellus </em>(Baker)<em> </em>and competition with annual weeds. Early-season weeds in chile pepper can be reduced by either barley, <em>Hordeum vulgare </em>L. or brown mustard, <em>Brassica juncea </em>(L.) Czern. cover crops; however, the potential of attracting <em>N. tenellus</em> should be factored into cover crop selection. In this study, abundance of leafhopper guilds was measured in field plots in Leyendecker, NM (2021-2022 and 2022-2023) and Los Lunas, NM (2021-2022) featuring a brown mustard ('Caliente Rojo'), barley ('Stockford'), or combination cover crop treatment. In a controlled environment study, viruliferous <em>N. tenellus </em>adults were subjected to dual-choice tests between brown mustard and one of two barley cultivars ('Stockford' or 'Valor'), and their presence on each plant after 24 h was recorded. A subsequent no-choice test trapped viruliferous <em>N. tenellus </em>on brown mustard, Stockford barley, or Valor barley for 24 h; after recording <em>N. tenellus </em>survival, leaf tissue was stained and analyzed for the presence of sheaths, superficial punctures, and eggs. Field results indicated that leafhopper guilds were three times more abundant in brown mustard treatments than Stockford barley or combination treatments. In dual-choice tests, <em>N. tenellus</em> demonstrated a nine times greater acceptance of brown mustard than either barley<em> </em>cultivar. In no-choice tests, <em>N. tenellus </em>trapped on Stockford barley faced reduced survival<em>.</em> Additionally, <em>N. tenellus </em>successfully ingested vascular fluid of brown mustard four times more often than <em>N. tenellus</em> trapped on barley. No eggs were laid on either barley cultivar, indicating its unsuitability as a host plant. This research indicates that barley is less likely than brown mustard to sustain <em>N. tenellus</em> populations that have the capacity to transmit BCTV to subsequently planted chile pepper. Further research is needed to understand the relationship between allelochemicals and <em>N. tenellus </em>feeding, survival, and reproduction.</p>