Balclutha rubrostriata (Melichar): Red streaked leafhopper

California Pest Rating
Balclutha rubrostriata (Melichar): Red streaked leafhopper
Hemiptera:  Cicadellidae
Current Pest Rating:  Q
Proposed Pest Rating:  A
FINAL Pest Rating:  A
Initiating Event:

In July 2014 USDA’s New Pest Advisory Group (NPAG) distributed a report recommending that the status of Balclutha rubrostriata (red streaked leafhopper) be changed to non-actionable for the entire United States.  The species was first found in Texas in 2008 during a wood borer survey and is now widespread and abundant in that state and spreading into Louisiana.  A pest rating proposal is needed to determine future direction.

History & Status:

BackgroundBalclutha rubrostriata feeds on a wide variety of grasses and is sometimes considered a pest in grass crops because it negatively impacts seed production.  Hosts include a variety of grass (Poaceae) species including rice (Oryza sativa), sugarcane (Saccharum officianarum), bluegrass (Bothriochloa spp.), King Ranch bluestem (B. ischaemum), Australian bluestem (B. bladhii), and little bluestem (Schizachyrium scoparium).  It has also been found on sesame (Sesamum indicum (Pedaliaceae)).  This leafhopper may be a vector of sugarcane white leaf phytoplasma.  The leafhopper has been found carrying the phytoplasma but it is currently unknown if the insect can transmit the phytoplasma to plants.  Balclutha adults, nymphs, or eggs are sometimes moved long distances by commerce in infested plants or as hitchhikers.

Worldwide Distribution: Balclutha rubrostriata is known to be present in parts of North Africa, Asia, Oceania, the Caribbean, and the Middle East.  In the United States it is present in Hawaii, Texas, Louisiana, Puerto Rico, and possibly Florida.

Official Control: Balclutha rubrostriata is not under official control in any other countries or states.

California DistributionBalclutha rubrostriata has never been found in California.

California Interceptions:  In 2003 a single female Balclutha sp. was intercepted on Malonggai leaves from Hawaii (PDR P205345) but could not be assigned a specific epithet.  It is likely that eggs and nymphs are intercepted more frequently but also cannot be identified.

The risk Balclutha rubrostriata would pose to California is evaluated below.

Consequences of Introduction:  

1) Climate/Host Interaction: Grasses are widespread in California and Balclutha rubrostriata is expected to be capable of establishing where they grow. The leafhopper receives a High (3) in this category.

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

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: The host range of Balclutha rubrostriata is thought to be limited to a wide variety of grasses, including rice.  The leafhopper receives a Medium (2) in this category.

Evaluate the host range of the pest. Score:

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: Leafhoppers are jumping insects with limited dispersal capabilities and most species have only one generation per year.  However, Balclutha rubrostriata has rapidly become abundant and widespread in Texas, demonstrating high reproductive potential.  Furthermore, the insects may be transported long distances through commerce in infested plants.  Balclutha rubrostriata receives a High (3) in this category.

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

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: Balclutha rubrostriata is known to lower yields in grass production and may be expected to increase production costs.  Growers in Australia treat with dimethoate to control the leafhopper.  However, despite its abundance the leafhopper has not yet emerged as a pest in Texas.  Balclutha rubrostriata receives a Medium (2) in this category.

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

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: Balclutha rubrostriata is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. The leafhopper may feed on several species of native grasses that are listed as threatened or endangered species.  The leafhopper is not expected to disrupt critical habitats.  The leafhopper is likely to trigger additional private treatment programs in grass production where seed yield is important.  Balclutha rubrostriata is not expected to significantly impact cultural practices, home/urban gardening, or ornamental plantings.  Red streaked leafhopper receives a High (3) 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:

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 Balclutha rubrostriata (red streaked leafhopper):  High (13)

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: Balclutha rubrostriata has never been found in California and receives a Not established (0) 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: High (13)

Uncertainty:

CABI lists yam (Discorea spp.), cotton (Gossypium spp.), and corn (Zea mays) as additional hosts of Balclutha rubrostriata but this does not appear to be supported by literature.  If these other crops are suitable hosts then the entry of this leafhopper to California could have additional economic and environmental impacts.

Conclusion and Rating Justification:

Red streaked leafhopper (Balclutha rubrostriata) has never been found in California.  If it were to enter the state, the leafhopper may have significant economic impacts on grass production, including rice.  The leafhopper may also have significant environmental impacts including triggering new chemical treatments in grass industries and by feeding on threatened and endangered grasses.  An “A” rating is justified.

References:

Newton, Leslie P.  2014.  NPAG Report on Balclutha rubrostriata (Melichar): Red streaked leafhopper.  New Pest Advisory Group (NPAG).  Plant Epidemiology and Risk Analysis Laboratory.  Center for Plant Health Science & Technology.


Responsible Party:

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


Comment Period:  CLOSED

The 45-day comment period opened on Jul 25, 2016 and closed on Sep 8, 2016.


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Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

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Pest Rating:  A