3 thoughts on “Beetle | Dyscinetus dubius”

1. Please see the California Rice Commission comments on the proposed change in posting of Dyscinetus dubius.

   1. Please see the comment letter from the California Rice Commission specific to the Dyscinetus dubius beetle.
      CRC Comments on Dyscinetus dubius beetle.pdf

      Kyle Beucke, Author
      California Department of Food and Agriculture
      1220 N Street, Room 221
      Sacramento, CA 95814

      Dear Mr. Beucke:

      RE: California Rice Commission comments on California Pest Rating Proposal for Beetle Dyscinetus dubius (Olivier) Coleoptera: Scarabaeidae From Pest Rating “Q” to Proposed Pest Rating “A”

      The California Rice Commission (CRC) is a statutory organization representing the entirety of the California rice industry consisting of 2,500 rice farmers and 40 marketers (CDFA FAC 71000-71138). We represent the California rice industry on regulatory issues for pesticides, air and water quality, conservation programs and public education. California is the second largest rice producing state in the United States, growing mostly Japonica medium grain on an average of 500,000 acres annually. In California, rice is one of the top 20 commodities, and the seventh largest commodity export, which contributes more than $5 billion annually to the state’s economy.

      We agree the Dyscinetus dubius is most likely to not be introduced into California. We do not receive rice shipments from Brazil and contamination of rice from banana shipments is unlikely. Your assessment supports our previous requests for an increase in industry coordination with the CDFA staff.
      The CDFA Pest Proposals and Final Ratings provides the following:
      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.

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

      CRC Response: The California rice growing region has a Mediterranean climate. Dyscinetus dubius would be manageable if found in California through our network of inspection, extension, research and regulation for pest management.

      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.

      – High (3) has a wide host range.

      CRC Response: Rice is not in the four listed plant families with Poaceae the closest to the crop. The Dyscinetus dubius would be controlled through the rice conventional pest management program.

      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.

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

      CRC Response: True of almost every insect pest found in California with infestation of rice from infected plant material extremely unlikely.

      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 dubiuswas 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.

      Evaluate the economic impact of the pest to California using the criteria below. Score:
      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).

      Economic Impact Score: High (3)
      – High (3) causes 3 or more of these impacts.

      CRC Response: What documentation exists on the level of crop yield losses to California rice? What evidence exists on the type and amount of production costs for California rice? The only threat to the California rice market is the listing of Dyscinetus dubius from “Q” to “A” rating. The change in pest rating would become the trade irritant.

      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

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

      Environmental Impact Score: 2

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

      Consequences of Introduction to California for Dyscinetus dubius: Medium (12)

      Add up the total score and include it here.

      –Medium = 9-12 points

      CRC Response: Dyscinetus dubius could trigger additional official or private treatment programs if the rating is changed from “Q” to “A”. Our industry would prefer to manage the pest without a change in the pest rating. That is, if the pest were ever established as a pest of California rice. As stated previously, the California rice industry has a unique network of extension, research and regulation for pest management.

      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.

      CRC Response: The CRC agrees with this conclusion and believes the review is based on assumptions that do not justify an “A” rating.

      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.

      Summary and Recommendations
      The CRC completely disagrees with the rationale for justifying the change in rating to “A” for Dyscinetus dubius on rice. No sound evidence exists for the “A” rating. The only threat to California rice is the CDFA arbitrary assessment to change the rating on a pest that does not exist on the crop. Changing the rating from “Q” to “A” would be devastating by creating the negative contribution effecting economics through trade impacts to the California rice industry. The assumptions for changing the ratings are inaccurate, so we offer the opportunity to provide additional input on California rice cultural practices.
      The CRC requests a meeting with your office and the rice industry prior to any final determination.

      Through our collaboration, we have a “Rice Team” consisting of the CRC, UC Davis, UC Cooperative Extension, Rice Research Board, Rice Experiment Station, rice growers and other rice industry representatives including a positive relationship with the county agricultural commissioners. Please contact me with questions for additional information and clarification on the comments provided in this letter.

      Sincerely,

      original signed by

      Tim Johnson
      President/CEO

      1. The commenter believes that Dyscinetus dubius is unlikely to become established in California and does not pose a significant threat to the state’s rice industry. In addition, the commenter believes that an “A” rating would negatively impact the rice industry. Each comment will be answered below:

         1. The California rice growing region has a Mediterranean climate, and D. dubius would be managed by the rice industry.

         Response: Rice is cited in this proposal as one of the crops that this beetle is known to attack. However, this beetle is highly polyphagous and attacks other crops as well. It should not be assumed that rice is the primary focus of this proposal. The known distribution of this beetle suggests that it might be capable of establishing in portions of southern or coastal California. As rice is not the only crop threatened by this beetle, any argument regarding the ability of the rice industry to combat this pest addresses only a portion of the potential risk if this species were introduced to California; other crops would be under threat as well.

         2. Rice is not in the four listed plant families (“Known Pest Host Range”). The pest would be controlled through the pest management program.

         Response: Rice (Oryza sativa) is in the family Poaceae, which is one of the listed host families for this pest.

         3. Almost every insect pest found in California can fly and could be dispersed artificially through movement of infested plant material, and infestation of rice from infected plant material is extremely unlikely.

         Response: Although this criterion is somewhat subjective, the ability of this beetle to fly and potential ability to be transported with potted plants seemed to justify a ranking of high dispersal ability. Several major commodities would be potentially threatened by this beetle and could serve as pathways for further dispersal.

         4. What documentation/evidence exists on the type and amount of production costs for and level of crop yield losses to California rice? Assigning an “A” rating to D. dubius is a threat to the rice industry.
         

         Response: As the beetle is not currently in California, no data on harm to California rice (or any other commodity) is possible. One can only point to other countries where the pest is a known pest of rice and other commodities. The very basis of risk assessment is to predict potential harm in the future so that steps can be taken to avert it. Due to the wide host range of this beetle, the possible economic impact does not depend only upon rice being threatened. Even without considering rice, this beetle is worthy of an “A” rating based on the general standards CDFA has used to rate insects for several decades. The commenter considers that the rice growing region of California is not likely to be invaded by this beetle and that infestation of rice is unlikely to occur through movement of infested plant material. If that is the case, assigning an “A” rating to D. dubius will not affect the rice industry.

         5. Assigning an “A” rating to this pest could trigger treatment programs. The rice industry would prefer to manage the pest without a change in the pest rating through their pest management network.

         Response: Dyscinetus dubius appears to pose a threat to California’s agriculture and environment. It is not currently known in California. If it were to appear, then immediate eradication efforts would be critical; an “A” rating ensures a rapid response. This beetle currently has a “Q” rating. For regulatory purposes, “Q”-rated pests are treated the same as “A”-rated pests.

         6. The commenter agrees with the assessment of the distribution of the pest in California, and states that the review is based on assumptions that do not justify an “A” rating.

         Response: This portion of the proposal states the currently-known distribution of the organism in the state. It does not address risk assumptions.

         7. The commenter disagrees with the “A” rating, stating that the CDFA was arbitrary in its assessment and that “The only threat to California rice is the CDFA arbitrary assessment to change the rating on a pest that does not exist on the crop.”

         Response: There are many different crops grown in California, and the CDFA must consider the possible impact of a pest on any of these over the entire state. There is often some degree of uncertainty involved in these assessments. The argument that assigning an “A” rating to D. dubius will negatively impact California’s rice industry may not be justified, as the beetle is a known pest of rice in other countries.

         After considering the Pest Risk Proposal and the comments, the following rating is recommended:

         Rating: A

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