USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648-9757, USA.
Environ Entomol. 2023 Feb 17;52(1):119-128. doi: 10.1093/ee/nvac104.
The threecornered alfalfa hopper (Spissistilus festinus) is a pest of grapevine, with damage caused by transmission of grapevine red blotch virus. Because grapevine is not a preferred host of the threecornered alfalfa hopper, abundance in vineyards depends on proximity to source habitats and presence of preferred hosts in vineyard understories. The potential for alfalfa fields and pastures in the Central Valley of California to serve as sources of threecornered alfalfa hopper was evaluated by quantifying parameters associated with threecornered alfalfa hopper reproductive and nutritional status. Laboratory studies determined that the threecornered alfalfa hopper is synovigenic, emerging as an adult prior to initiation of oogenesis and that females have multiple rounds of egg production. Alfalfa fields, irrigated pastures, and vineyards were sampled monthly. Adults were observed year-round in alfalfa fields and pastures, with populations peaking in fall. Gravid females were observed from February through November. While rare, adult threecornered alfalfa hoppers were collected from 2 of 4 sampled vineyards. In spring, adults were observed in samples collected from vineyard ground cover. In fall, adults were observed in samples collected from vineyard ground cover and foliage samples. Samples collected from pastures and vineyards were male biased, whereas equal numbers of males and females were observed in alfalfa fields. Adults collected from alfalfa fields were larger, heavier, and had greater estimated energetic reserves than adults collected from pastures. Adults collected from vineyards were of above average size and had relatively high estimated energetic reserves. Results suggest that alfalfa fields are more likely to serve as sources of threecornered alfalfa hoppers than irrigated pastures and that differences in male and female behavior may affect rates of pathogen transmission.
三叶苜蓿盲蝽（Spissistilus festinus）是葡萄的一种害虫，通过传播葡萄红斑病毒造成损害。由于葡萄不是三叶苜蓿盲蝽的首选宿主，因此葡萄园中的三叶苜蓿盲蝽丰度取决于其与源栖息地的距离以及葡萄园下层植被中首选宿主的存在。通过量化与三叶苜蓿盲蝽生殖和营养状况相关的参数，评估了加利福尼亚州中央谷的苜蓿田和牧场作为三叶苜蓿盲蝽源的潜力。实验室研究表明，三叶苜蓿盲蝽是同步发生的，在卵发生开始之前就以成虫形式出现，并且雌性有多次产卵。每月对苜蓿田、灌溉牧场和葡萄园进行采样。全年都可以在苜蓿田和牧场上观察到成虫，其种群在秋季达到高峰。从 2 月到 11 月都可以观察到带卵的雌性。虽然很少见，但在 4 个抽样葡萄园中有 2 个采集到了成年三叶苜蓿盲蝽。在春季，从葡萄园地面覆盖物中采集的样本中观察到成虫。在秋季，从葡萄园地面覆盖物和叶样本中采集的样本中观察到成虫。从牧场和葡萄园采集的样本雄性偏多，而在苜蓿田中观察到的雄性和雌性数量相等。从苜蓿田采集的成虫体型较大、较重，估计的能量储备也较大，而从牧场采集的成虫则体型较小、较轻，估计的能量储备也较小。从葡萄园采集的成虫体型适中，估计的能量储备相对较高。结果表明，苜蓿田比灌溉牧场更有可能成为三叶苜蓿盲蝽的来源，并且雌雄行为的差异可能会影响病原体的传播速度。
