1. Insects Affecting Production of Native Legume Seed in the Great Basin
Jim Cane
USDA/ARS Bee Biology
& Systematics Lab
Logan UT
Bob Hammon
Tri River Cooperative Extension
Grand Junction CO

2. “Natural controls” Insect Pests of Native Plants?
Economic considerations
“Natural controls”

3. Hedysarum boreale Northern Sweetvetch
70%+ seed loss to seed weevils at Meeker CO 1990

4. Dalea ornata Western prairie clover
Seed weevils widespread!!

5. Lupinus argenteus Silvery Lupine
Significant weevil damage to seed in field collections

6. Astragalus filipes Basalt Milkvetch
5 species of weevils damaging seed in 2003/04
Several root boring weevils reported from Astragalus

7. 2003 Astragalus collection sites

8. Weevils Curculionidae - True weevils
Tychius (ASFI, HEBO, LUAR)
Brentidae – Straight-snouted weevils
Taxonomic confusion!!
Curculionidae, Apionidae, Brentidae
Apion (DAOR, LUAR)
Bruchidae - Seed weevils
Acanthoscelides (ASFI, HEBO, DAOR)

9. Bruchidae Brentidae Curculionidae D. ornata A. filipes H. boreale
L. argenteus
Bruchidae
Acanthoscelides
aureolus L X
daleae
fraterculus
oregonensis
pullus
Brentidae
Apion
amaurum
proclive
oedorhychum
Curculionidae
Tychius
lineellus
semisquamosus
tectus

10. Bruchidae – Seed Weevils
Acanthoscelides
Head hypognathous (pointed downward)
Antennae arise from base of eye
Tip of abdomen not covered by elytra

11. Acanthoscelides oregonensis
Most seed weevils
we are dealing
with are < 2.5 mm
In length
2mm

12. Brentidae Curculionidae
Agave weevil
Scyphophrus acupunctatus
Hollyhock weevil
Apion longirostre

13. Weevil Larvae Found within seed pod Root feeders
May be within normal-looking seed
Well developed head capsule
Legs reduced or absent

14. Tychius Life History Feed on Fabaceae: Papilionoideae Seed predators
Adults feed on flowers/ pollen
Oviposit in immature ovaries/pods
Larvae feed on several seeds within pod
External feeders
Pupation in soil
Pupation in pods aberrant??
Overwintering as adult in soil
Clark, W.E The curculionid genus Tychius Germar: Natural history and coevolution with leguminous host plants. Southwestern Entomologist 2:

15. Acanthoscelides Life History
Many species, host plants
Large diversity of life history
Oviposition on pods, some spp on seed
External or internal feeding on seeds, may eat 1 seed completely before moving on
Multiple generations for some species
Silken cocoon against side of pod, some spp within a seed

16. Handling Collected Seed Don’t bring them home alive
Inspect seed for damage
Adult weevils on plant material
Larvae within seed
Inspect healthy-looking seed
Keep samples for ID
Larvae for rearing to adult
Fumigate with No Pest Strip
Cut into 1” strips
48h in sealed container

17. Management – Field Collection Sites
Anticipate problems
Monitor the site
Sweep net
Nocturnal samples
Pre-bloom soil drench
Bayer Advanced Tree & Shrub Insect Control Concentrate
Imidacloprid
Cheap, readily available, easy to apply

18. Management – Field Plantings
Monitoring with sweep net
NOCTURNAL!!!!!
Preventative controls
Target adults pre-oviposition
Systemic insecticide
Prebloom imidacloprid
Contact insecticide
Residual pyrethroid
Pollinator concerns
Non-lethal effects

19. Seed Predator Challenges
Research needs
Many species
Life history diversity
Taxonomy challenges
Geographic differences
Widespread distribution
Many legume plantings will be affected
Yearly changes
We don’t know what next years challenge is

20. Seed Production Pesticide Labels
No labels for “Forbs grown for Seed”
Field grown ornamentals
listserv

21. Bob Hammon
Tri River Cooperative Extension
P.O. Box 20,
Grand Junction CO
(970)