California Pest Rating for
Beetle | Dyscinetus dubius (Olivier)
Pest Rating: A
PEST RATING PROFILE
Dyscinetus dubius (Olivier) is currently Q-rated. A permanent pest rating proposal is required to support an official pest rating.
History & Status:
Background: Dyscinetus dubius is a reddish-brown beetle approximately 1.5 to 2 cm in length. The larvae are whitish C-shaped grubs that live underground and feed on roots. This beetle is reported to be a pest (through larval feeding) of potato, rice, and soybeans in Brazil (Ferreira & Barrigossi, 2006; Ferreira & Martins, 1984), but it has also been associated with, and may feed on corn and elephant ear (Xanthosoma sagittifolium) (Araceae) (Joly & Escalona G., 2010).
Worldwide Distribution: Dyscinetus dubius is widely distributed throughout Mexico, the Caribbean (including Cuba and Trinidad), Central America (including Costa Rica, Guatemala, Honduras, Nicaragua, and Panama), and South America (including Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, French Guiana, Paraguay, Suriname, and Venezuela) (Ferreira & Martins, 1984; Joly & Escalona G., 2010; Neita-Moreno & Yepes, 2011).
Official Control: Dyscinetus dubius is a prescribed pest in Guyana (Caribbean Invasive Alien Species Network).
California Distribution: Dyscinetus dubius is not known to be present in California.
California Interceptions: Dyscinetus dubius has been intercepted at a border station on bananas from Ecuador (1183969).
The risk Dyscinetus dubius would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Dyscinetus dubius appears to be restricted to areas with a subtropical to tropical climate, and this may be expected to limit the potential distribution of this species in California. This beetle is reported to feed on at least four plant families, including Poaceae and Solanaceae, and would likely find suitable food plants over much of the state. This beetle could possibly become established over a limited portion of California. Therefore, Dyscinetus dubius receives a Medium (2) 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: Dyscinetus dubius is a generalist and has been reported to feed on plants in the families Araceae, Fabaceae, Poaceae, and Solanaceae. Therefore, it receives a High (3) 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: Dyscinetus dubius is collected at light, so it can fly. It can be dispersed artificially through movement of infested plant material. 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: Dyscinetus dubius is a recognized pest of several crops, among them rice. California rice production in 2016 was valued at $649 million (USDA, 2018). Potatoes and corn, which are also grown in California, could also be impacted. If Dyscinetus dubius was established in California, it could lower crop yield and increase production costs of these crops. It could also lead to a loss of markets. Therefore, it receives a High (3) in this category.
Economic Impact: A, B, C
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: 3
– 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: If Dyscinetus dubius became established in California, it could trigger treatment programs if it became a crop pest. Therefore, it receives a Medium (2) in this category.
Evaluate the environmental impact of the pest on California using the criteria below.
Environmental Impact: D
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: 2
– 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 Dyscinetus dubius: Medium (12)
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: Dyscinetus dubius is not known to be present 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.
7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (12)
Dyscinetus dubius appears to be currently limited to areas with a subtropical or tropical climate. This beetle may not be capable of becoming established in California, and if it is, it could be limited to a very small area. Rice in California is typically grown in flooded conditions, and this may reduce or eliminate the potential of D. dubius to impact this crop, although other crops, including corn and potatoes, could still be affected (California Rice Commission, 2018). Other plants, including native California species that this beetle has not been previously exposed to, could also be attacked in California, which could result in additional impacts on the environment.
Conclusion and Rating Justification:
Dyscinetus dubius is a recognized pest in Latin America. This beetle is not known to be present in California. However, it affects crops that are grown in the state, including rice and potatoes. If it became established in the state, it could have economic and environmental impacts. For these reasons, an “A” rating is justified.
California Rice Commission. 2018. How rice grows. Accessed 4 January 2018. http://calrice.org/industry/how-rice-grows
Caribbean Invasive Alien Species Network. Guyana. Accessed 3 January 2018. http://www.ciasnet.org/countryprofiles/guyana
Ferreira, E. & Barrigossi, J.A.F. 2006. Insetos Orizívoros da Parte Subterrânea. San Antônio de Goiás, Goiás, Brazil. 52 pp.
Ferreira, E. & da S. Martins, J.F. 1984. Insetos prejudiciais ao arroz no Brasil e seu controle. EMBRAPA-CNPAF. Goiânia, Goiás, Brazil. 67 pp.
Joly, L.J. & Escalona G., H.E. 2010. El género Dyscinetus Harold (Coleoptera: Scarabaeidae: Dynastinae: Cyclocephalini) en Venezuela y la descripciόn de una nueva especie. Papéis Avulsos de Zoologia. 50(14): 203-231.
Neita-Moreno, J.C. & Yepes, F. 2011. Descripciόn de la larva y pupa de Dyscinetus dubius (Coleoptera: Melolonthidae: Dynastinae: Cyclocephalini). Revista Colombiana de Entomología. 37(1): 152-156.
Symbiota Collections of Arthropods Network. Accessed 20 November 2017. http://scan1.acis.ufl.edu
United States Department of Agriculture. 2016 State Agriculture Overview. California. Accessed 4 January 2018. https://www.nass.usda.gov/Quick_Stats/Ag_Overview/stateOverview.php?state=CALIFORNIA
Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741; plant.health[@]cdfa.ca.gov.
Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov
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Pest Rating: A
Posted by ls