Abstract: In greenhouse experiments, Ohio accessions of 22 weed species representing 13 dicot families were screened as alternative hosts of soybean cyst nematode (SCN, Heterodera glycines). Purple deadnettle (Lamium purpureum), henbit (Lamium amplexicaule), field pennycress (Thlaspi arvense), shepherd's-purse (Capsella bursa-pastoris), and a susceptible soybean (Glycine max) cultivar produced SCN population densities of 510, 155, 73, 1, and 366 cysts/450 cm3 soil, respectively, 5 wk after inoculation with eggs from a race 3 SCN population. Purple deadnettle was also a strong host of race 1 SCN and a weak host of race 6 SCN. Average numbers of eggs/cyst among race 3 hosts were highest in purple deadnettle (357), followed by soybean (292), field pennycress (266), henbit (122), and shepherd's-purse (none detected). To our knowledge, henbit is the only SCN host identified here that has been previously identified as a host. The weeds identified as SCN hosts in this study have a winter annual life cycle in Ohio and may serve as sites for SCN reproduction in infested fields during the early or late growing season and when soybean plants are absent.
Nomenclature: Field pennycress, Thlaspi arvense L. #3 THLAR; henbit, Lamium amplexicaule L. # LAMAM; purple deadnettle, Lamium purpureum L. # LAMPU; shepherd's-purse, Capsella bursa-pastoris (L.) Med. # CAPBP; soybean, Glycine max (L.) Merr. ‘Corsoy 79’; soybean cyst nematode, Heterodera glycines Ichinohe.
Additional index words: Alternate hosts, integrated weed management, CAPBP, LAMAM, LAMPU, THLAR.
Abbreviations: SCN, soybean cyst nematode.