Reproduction of Soybean Cyst Nematode Populations on Field Pennycress, Henbit, and Purple Deadnettle Weed Hosts

Several weeds serve as alternative soybean cyst nematode (SCN) hosts. Still, the relative reproductive capacity of SCN HG types (Heterodera glycines type) on weed hosts relative to soybean is not well understood. This study examined the reproduction of three South Dakota endemic SCN populations—PSCN-1 (HG 0), PSCN-2 (HG 2.5.7), and PSCN-3 (HG 7)—on purple deadnettle, field pennycress, and henbit. The Relative Female Index (RFI) was calculated to compare SCN reproduction relative to the susceptible soybean check. Weed hosts, HG types, and their interactions influenced SCN reproduction. Henbit (RFI = 51.8) and purple deadnettle (RFI = 47.6) roots had a similar high RFI, whereas field pennycress (RFI = 23.04) had a lower RFI. Similarly, SCN populations PSCN-1 and PSCN-3 had a similar RFI of 36.9 and 37.2, respectively, while the population PSCN-2 had a higher RFI of 44.9 across weed hosts. A significant interaction between PSCN-1 and purple deadnettle was observed where the RFI was the highest (RFI = 53.3). These results indicate that these weed hosts support endemic SCN populations, and the HG type influenced reproductive success, further complicating SCN management. Hence, SCN presents a significant challenge in the new prospect of incorporating field pennycress host as an oilseed cover crop in the Midwest’s corn–soybean production system.