Metamasius hemipterus | Pest Rating Proposals and Final Ratings

California Pest Rating for

Metamasius hemipterus (L.): West Indian Sugarcane Weevil

Pest Rating: C

PEST RATING PROFILE

Initiating Event:

February 26, 2014, USDA distributed a Deregulation Evaluation of Established Pests (DEEP) report proposing to change the status of Metamasius hemipterus, West Indian sugarcane weevil, from actionable to non-actionable for the continental United States. The weevil would remain actionable for Hawaii and the Pacific territories. The insect is currently C-rated by CDFA, so a pest rating proposal is needed to determine future direction.

History & Status:

Background: The larvae of Metamasius hemipterus are borers that tunnel through the stems and petioles of tropical plants, causing extensive damage^3. They are considered an economic pest in Florida³. The weevil feeds primarily on coconut, banana, and sugarcane²; it usually attacks plants that are already damaged. Secondary hosts include a variety of palms, lantana, pineapple, cassava, guava, sorghum, corn, and Mora excelsa^1,2. Metamasius hemipterus can spread long distances through commerce in infested plants and fruit, especially bananas.

Worldwide Distribution: Metamasius hemipterus appears to be native to Central America and/or northern South America¹. From there it has spread through much of the Caribbean and Cameroon, Congo, Equatorial Guinea, Gabon, and Nigeria in Africa. It was found in Florida in 1984.

Official Control: Metamasius hemipterus is considered a quarantine pest in Europe².

California Distribution: There are specimens of Metamasius hemipterus in the California State Collection of Arthropods from the following counties: Los Angeles, San Diego, San Francisco, Contra Costa, and Calaveras.

California Interceptions: There is only one interception of Metamasius hemipterus recorded in the PDR database. This was at the border station in Blythe in 2001 on bananas of unknown origin. The weevil is frequently intercepted by USDA on bananas from Central and South America.

The risk Metamasius hemipterus (West Indian sugarcane weevil) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The present distribution of Metamasius hemipterus corresponds to USDA plant hardiness zones 9-13. This corresponds to much of California. The weevil receives a High(3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 3

– 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: Metamasius hemipterus is known to feed on 20 species of plants in 6 families. The weevil receives a Medium(2) in this category.

Evaluate the host range of the pest. Score: 2

– 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: Metamasius hemipterus has a high reproductive rate, with each female laying an average of 500 eggs³. The weevils are reported to not disperse long distances naturally, but they can spread long distances through commerce in infested plants or fruit, especially bananas. Metamasius hemipterus receives a High(3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score: 3

– 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: Metamasius hemipterus is reported to be a pest of sugarcane and ornamental palms. However, it is present in California and is not reported to lower crop yield, lower crop values, trigger lost markets, alter cultural practices, vector other organisms, or interfere with water supplies. The weevil receives a Low(1) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score: 1

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.

– 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: Metamasius hemipterus has entered California and is not known to lower biodiversity, disrupt natural communities, or change ecosystem practices. It is not known to directly affect threatened or endangered species or disrupt critical habitats. There are no reports of the weevil triggering treatment programs or altering cultural practices, home/urban gardening, or ornamental plants. Metamasius hemipterus receives a Low(1) in this category.

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

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.

Score the pest for Environmental Impact. Score: 1

– 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 Metamasius hemipterus (West Indian Sugarcane Weevil): Medium(10)**

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: Metamasius hemipterus is thought to have established a widespread distribution in California. The weevil receives a High(-3) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

–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:

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

Uncertainty:

Historically some scientists have treated what is now known as Metamasius hemipterus as three distinct species². It is possible that there could be cryptic species in this group that are absent from California and more damaging than the weevil we have here.

Conclusion and Rating Justification:

Metamasius hemipterus is reported to be present in California and is not known to cause any significant economic or environmental impacts. A C-rating is justified.

References:

¹Culliney, T.W. 2014. Deregulation Evaluation of Established Pests (DEEP); DEEP Report on Metamasius hemipterus (L.): West Indian Sugarcane Weevil.

²European and Mediterranean Plant Protection Organization (EPPO) data sheet on Metamasius hemipterus. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CDwQFjAD&url=https%3A%2F%2Fwww.eppo.int%2FQUARANTINE%2FPest_Risk_Analysis%2FPRAdocs_insects%2Fdraft_ds%2F09-15171%2520DS%2520Metamasius%2520hemipterus.doc&ei=yRRQU8PBN8PmyQHaloC4Cw&usg=AFQjCNFWGRjZa4Q95nqilDkxnpstEbCwWw&bvm=bv.64764171,d.aWc

³Weissling, Thomas J. and Robin M. Giblin-Davis. 2013. Featured Creatures: Silky Cane Weevil. http://entnemdept.ufl.edu/creatures/orn/silky_cane_weevil.htm

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.

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