|Scientific Name: Hedysarum boreale Nutt.
Common Name: Utah Sweetvetch, Northern Sweetvetch
Plant Abbreviation: HEBO
Description: Utah sweet vetch is a nitrogen fixing legume that grows on western rangelands. There is significant seed production in CO, UT and ID. 'Timp' is a released variety and several ecotypes are in production. A widespread seed weevil, Acanthoscelides sp. has reduced yield by 75% in extreme situations. Lygus bugs can reduce seed set. The larvae of several native butterflies and moths can feed on foliage and seed pods, although we have not yet seen significant damage from them. Sweetvetch production is also impacted by a rust disease and root rot disease which are poorly understood.
|Hedysarum Seed Weevil|
|Scientific Name: Coleoptera: Bruchidae: Acanthoscelides sp.
The Hedysarum seed beetle is widespread across the west. It is recorded in HEBO seed production plots in CO, UT and ID. Losses of 75% were recorded in the early 1990's in a field at Meeker, CO. The beetle was originally identified as A. fraterculus (1) , but recent taxonomy work has shown that it is probably an undescribed species. A. fraterculus is recorded from several species of legumes but it is possible that the undescribed species has a more limited host range.
Adult beetles are about 1.5 mm in length and brown in color. Their snout is broad. Males appear in the field shortly before the first flowers bloom, and females are present at first bloom. Beetles are easily found using a sweep net, but are not readily apparent with simple visual searches.
Eggs have not been described. They are laid either in or on developing seed pods.
Larvae spend most of their life within infested seeds. The seed in the upper picture was damaged when a larva chewed its way out.
Pupation is probably in the soil but we have not yet seen a pupa in the field.
|It is important to monitor HEBO seed fields at first bloom for seed
beetles. A sweep net is an excellent, inexpensive, monitoring tool. We
have treated fields that have one or two seed beetles per ten sweeps.
There are no good thresholds set, but if beetles are easily found and
you wish to maximize production, an insecticide application may be
used. Bees will be visiting the field when flowers appear so it is
important to time a spray as soon as possible before bloom appears.
Pyrethroid insecticides work very well against adult beetles. If
flowers are present in the field, spray at night, when they have time
to dry before bees become active in the morning. Allowing the spray to
dry before bees become active will minimize bee kill.
Keep monitoring seed beetle activity during bloom. If beetles appear during bloom, a night time application of a non residual insecticide may work to reduce the beetle numbers while protecting bees.
|Utah Sweet Vetch in Colorado.|
|Sweep net sampling of a field of Utah sweetvetch.|
|Sweetvetch production at Western Colorado Research Center at Rogers Mesa. This field is being grown for the Uncompahgre Project.|
|For more information visit the USDA Natural Resources Conservation Service Plant Database|
This page was updated on April 26, 2014