A Seed Bug | Ochrimnus mimulus (Stal)

California Pest Rating for
Ochrimnus mimulus (Stål): A Seed Bug
Hemiptera: Lygaeidae
Pest Rating: A



Initiating Event:

Ochrimnus mimulus is currently Q-rated.  A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background:  Adult Ochrimnus mimulus measure 5-6 mm in length and are grayish or brownish with pale yellow margins on the forewings and the pronotum (Hoffman, 1996).  This bug is found on and feeds on flowers of Asteraceae.  Baccharis species appear to be the preferred host, but feeding and development can take place on other genera as well.  Eggs are laid in the flowers, and the nymphs feed on these (Gould and Sweet, 2000; Palmer, 1986).  Feeding on flowers reduces seed production by the host plant.  Experiments have shown that this species will attack numerous genera of Asteraceae.  This lack of host specificity made it inappropriate as a biological control organism for the introduced weed Baccharis halimifolia in Australia (Gould and Sweet, 2000).

Worldwide Distribution:  Ochrimnus mimulus occurs in the eastern United States (from Virginia south to Florida and west to Texas), Mexico, and Central America (Cancino and Blanco, 2002; Hoffman, 1996; Slater and Baranowski, 1990).

Official Control: Ochrimnus mimulus is not known to be under official control anywhere.

California Distribution:  Ochrimnus mimulus is not known to occur in California (Symbiota Collections of Arthropods Network).

California Interceptions:  Ochrimnus mimulus has been intercepted on rice, oranges, and bee colonies from Texas (CDFA Pest and Damage Report Database, 2018).

The risk Ochrimnus mimulus would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Ochrimnus mimulus is found over a wide area, from Virginia to Mexico, suggesting that this bug has a wide climatic tolerance. Baccharis, the preferred host genus of mimulus, includes many species that are present in California (Calflora).  It appears likely that O. mimulus could become established over a large portion of California.  Therefore, Ochrimnus mimulus receives a High (3) in this category.

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Ochrimnus mimulus appears to be mostly restricted to the Asteraceae, although it feeds on multiple genera within this family. Therefore, it receives a Medium (2) in this category.

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Ochrimnus mimulus can apparently fly (it is collected at light). Therefore, it receives a Medium (2) in this category.

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Ochrimnus mimulus is not known to be an economic pest, even though it is found over a wide area.  It appears unlikely that it would become an economic pest in California if it became established in this state.  Therefore, it receives a Low (1) in this category.

Economic Impact:

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 1

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

– High (3) causes 3 or more of these impacts.

5) Environmental Impact: Ochrimnus mimulus has been shown to have broad feeding preferences within the family Asteraceae and it prefers the genus Baccharis. Coyote brush, Baccharis pilularis, is a dominant shrub of coastal scrub in California.  If O.mimulus attacked this plant, it could impact species of plants and animals that live in these communities.  California also has rare Baccharis species, including Baccharis vanessae R.M. Beauch (Encinitas baccharis), that could be threatened by O. mimulus (Calflora).  Therefore, it receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact: A, B

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact Score: 3

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Ochrimnus mimulus: Medium (11)

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Ochrimnus mimulus is not known to occur in California.  It receives a Not established (0) in this category.

–Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (11)


Even if O. mimulus is capable of becoming established in the state, it is not certain that it would have a significant impact on native plant species.  If this insect became established in California, it could possibly attack crop plants in the family Asteraceae, including artichoke, safflower, and tarragon, although it is not known how much economic damage (if any) would result.

Conclusion and Rating Justification:

Ochrimnus mimulus is a flower-feeding insect that is not known to be present in California.  It poses a threat to native California plants, including rare species.  For these reasons, an “A” rating is justified.


Calflora.  2018.  Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria.  Accessed April 3, 2018: http://www.calflora.org

Cancino, E. R. and Blanco, J. M. C.  2002.  Artrópodos terrestres de los estados de Tamaulipas y Nuevo León, México.  Universidad Autónoma de Tamaulipas, Ciudad Victoria, Tamaulipas, México.

CDFA Pest and Damage Report Database. 2018. Ochrimnus mimulus. Plant Health and Pest Prevention Services. CA Department of Food and Agriculture. Accessed April 9, 2018:  http://phpps.cdfa.ca.gov/user/frmLogon2.asp

Gould, G. G. and Sweet, M. H.  2000.  The host range and oviposition behavior of Ochrimnus mimulus (Hemiptera: Lygaeidae) in central Texas.  The Southwestern Naturalist 45:15-53.

Hoffman, R. L.  1996.  The Insects of Virginia.  Number 14: Seed Bugs of Virginia.  Virginia Museum of Natural History, Martinsville, Virginia.

Palmer, W. A.  1986.  Host specificity of Ochrimnus mimulus (Stål) (Hemiptera: Lygaeidae) with notes in its phenology.  Proceedings of the Entomological Society of Washington 88:451-454.

Slater, J. A. and Baranowski, R. M.  1990.  Arthropods of Florida and Neighboring Land Areas.  Volume 14: Lygaeidae of Florida (Hemiptera: Heteroptera).  Division of Plant Industry, Gainesville, Florida.

Symbiota Collections of Arthropods Network.  Accessed April 3, 2018: http://scan1.acis.ufl.edu


Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741; plant.health[@]cdfa.ca.gov.

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

6/21/18 – 8/5/18


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Pest Rating: A


Posted by ls