Evaluation of Weed Species from the Northern Great Plains as Hosts of Soybean Cyst Nematode

Weeds can be alternate hosts of soybean cyst nematode (SCN), a major pathogen of soybean in the United States. Weed species from the northern soybean production area of North Dakota-northern Minnesota have not been evaluated for host suitability. Fifty-one weed species with multiple collections from different locations, representing 13 families were evaluated as hosts of SCN. Weeds were inoculated with SCN HG type 0 and a female index (FI) was calculated by comparing reproduction to that on Barnes, a susceptible soybean cultivar. Thirty-three weed species had not previously been tested. For 20 weed species, no reproduction on roots was observed on any collection. For 31 weed species, SCN females developed on roots of one or more collection, but only two weeds, henbit and field pennycress, allowed substantial reproduction with average FI's of 30.5 to 38, respectively; the other 29 species had average FI's of less than 10 and thus were defined as poor hosts. Twenty-six of the weed species from 11 plant families were newly identified hosts of SCN. Collections of species varied in host suitability. Although most weeds were non-hosts or poor hosts, the number of weeds that supported limited SCN reproduction indicates that weed hosts could influence SCN survival and reproduction in the upper Great Plains. Few weed species, however, are major hosts of SCN in this region. Accepted 10 December 2014. Published 28 January 2015. The objective of this research was to determine the soybean cyst nematode (SCN) host suitability of 51 weed species using multiple collections originating from North Dakota and northern Minnesota. The results from this research may be helpful for developing or modifying weed management tactics that will limit the survival and proliferation of SCN in the soybean production areas of North Dakota and northern Minnesota.