California Pest Rating for
Turkey Berry | Solanum torvum
Solanales: Solanaceae
Pest Rating: C | Proposed Seed Rating: N/A
PEST RATING PROFILE
Initiating Event:
Solanum torvum was recently intercepted by Los Angeles County Agricultural commissioner’s office at Long beach on 7/20/2017. Molecular analysis has confirmed the identification of this species on 8/11/2017. This invasive weed has been given a temporary Q rating. A pest rating is required to assign a permanent rating for this species.
History & Status:
Background: Solanum torvum is an evergreen, multi-branched shrub or small tree that grows to 16 feet high. Leaves bear star shaped (stellate) hairs and scattered, flattened, broad-based, straight to slightly hooked prickles. Fruits are globose to ovoid, about half an inch wide and borne in erect clusters. Each fruit contains about 200 seeds (FDACS). The root system includes a deep and strong woody taproot with numerous woody laterals. Solanum torvum grows in a wide range of habitats throughout the tropics and the subtropics. It grows best in warm, moist, fertile conditions but once established it can withstand drought by shedding its leaves (CABI 2016). It is cultivated for its edible fruits that are eaten when immature (Langland and Burks, 1998)
Solanum torvum invades human disturbed open sites and is a major weed in pastures, roadsides, wastelands and plantations. It prefers moist, fertile soil but can also tolerate draught. It can form dense thickets in disturbed areas such as vacant lots, brushy pastures, recently abandoned farms, landslides and river banks; it is considered a weed in Florida, Hawaii, Papua New Guinea, French Polynesia and Tonga (Wagner et-al. 1999)
Worldwide Distribution: Solanum torvum is native to the Antilles (Wagner et al. 1999). Langeland and Burks (1998) report that S. torvum is native from Mexico to Peru and Venezuela, and in the West Indies and Bermuda where it occurs in wet thickets, dry brushy plains, woodland clearings, and rocky hillsides. It is cultivated throughout the world for its edible fruits (Wagner et al. 1999) and has become a pantropical weed. S. torvum is reported as a weed in Florida, Hawaii, Australia, French Polynesia, Tonga, Samoa, Papua New Guinea, and elsewhere (PIER 2003, PLANTS 2003).
Official Control: Solanum torvum is reported as a harmful weed in China, Fiji, French Polynesia, Israel, Republic of Korea and Peru (PCIT-PExD). In the U.S., it is a federal noxious weed. This species has been listed as a noxious weed in Alabama, Florida, Hawaii, Minnesota, North Carolina, Vermont, Massachusetts, South Carolina, Oregon and California (USDA- NRCS)
California Distribution: Solanum torvum has not been found growing in the natural environment of California.
California Interceptions: Solanum torvum was intercepted seven times between January 1, 1990 and August 22, 2017 by CDFA’s high risk inspections, dog teams, and project survey for weeds. Most of the interceptions have been in shipments from Florida.
The risk Solanum torvum (turkey berry) would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Solanum torvum has established as a weed in the tropics of Florida and Hawaii. Since this species predominantly dominates human disturbed open sites and is rarely found on naturally disturbed sites (Nature Serve Explorer 2017), it has a limited potential of becoming established in sub-tropical areas in southern California and the central coast. Solanum torvum receives a Low (1) 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: Solanum torvum does not require one particular host, but grows wherever ecological conditions are favorable. Even though it can grow and establish in disturbed and open areas, it might grow poorly in the lower humidity environment of California. This species cannot survive under closed forest canopy areas (PIER (Pacific Islands Ecosystems at Risk). It receives a Low (1) 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: Solanum torvum reproduces solely by seeds. Seedlings establish their roots quickly and become woody. Pollination is by insects. The seeds are spread by fruit eating birds and bats as well as by construction machinery and contaminated soil (CABI: Datasheet: Solanum torvum). This species was initially introduced to many areas through cultivation of its edible fruit. Unless introduced to California through cultivation, it is not likely to spread and get established. It receives a Medium (2) 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: Solanum torvum is an invasive weed of pastures, roadsides and open native vegetation. It is also found in cassava and other perennial crops not exposed to cultivation (CABI) and can potentially reduce yield of these crops. None of these crops are grown in California. If this species were to establish in CA, use of various control methods could increase crop production costs. torvum is potentially poisonous to animals and possibly carcinogenic to humans. (Cuda and Parker et. al 2002). S. torvum is resistant to Meloidogyne spp and is used as a rootstock for grafting tomatoes in susceptible areas. Its resistance to Pseudomonas solanacearum and phomopsis fruit rot has also been reported (CABI). It receives a Medium (2) in this category.
Evaluate the economic impact of the pest to California using the criteria below.
Economic Impact: B, F
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: 2
– 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: Establishment of Solanum torvum can impact native biodiversity in the wet tropics due to its ability to form large, impenetrable thickets that can displace native species and alter vegetation structure in formerly open areas. However, it is also possible that its impact will not increase in future. (Nature Serve 2017). It receives a Medium (2) in this category.
Environmental Impact: A
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: 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 Solanum torvum (turkey berry): Low (8)
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: Solanum torvum has never been found in the environment 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: Low (8)
Uncertainty:
Solanum torvum is a federal noxious weed that may be introduced to California, as it is cultivated in certain parts of the world for its edible fruit. If introduced either through cultivation or by artificial means, it is less likely to spread to open, disturbed and abandoned farm land, pastures and riverbanks because of limited availability of water in California. Presence of similar Solanum species can complicate identification; however, early detection surveys in California can confirm the presence and possibly eradication this species if it were found in a small area. Wet tropical weeds can become nursery or row crop weeds in CA, but this is not common.
Conclusion and Rating Justification:
Solanum torvum (turkey berry) has never been found in the environment of California; it is less likely to have a significant economic and environmental impact if it were to enter the state. Nevertheless, it could be invasive in limited, irrigated areas & it is a federal noxious weed. Therefore a “C” rating is justified.
References:
Solanum Torvum – UF/IFAS Center for Aquatic and Invasive species, Florida Department of Agriculture and Natural Resources (FDACS)
Center for Agriculture and Biosciences International (CABI) Datasheet: Solanum Torvum (turkey berry).
Cuda, J.P., Parker, P.E. and Coon, B.R. et al. 2002. Evaluation of exotic Solanum spp. (Solanales: Solanaceae) in Florida as host plants for the leaf beetles Leptinotarsa defecta & L. Texan (Coleoptera: Chrysomelidae). Florida Entomologist. 85(4): 599-610.
Langeland, K.A. and K.C. Burks. 1998. Identification and Biology of Non-Native Plants in Florida’s Natural Areas. University Press of Florida, Gainesville, FL. Nature Serve Explorer 2017. Solanum torvum
PIER (Pacific Islands Ecosystems at Risk). 2002. Invasive Plant Species: Solanum torvum. Available: http://www.hear.org/pier
PLANTS (National Plants Database). 2003. Online database. United States Department of Agriculture (USDA), Natural Resources Conservation Services (NRCS), National Plant Data Center, Baton Rouge, LA. Available: https://plants.usda.gov/core/profile?symbol=SOTO4
Pest and Damage Report Database, Plant Health And Pest Prevention Services, California Department of Food and Agriculture.
Starr, Forest, Starr Kim and Lloyd Loope, April 2013, United States Geological Survey—Biological Resources Division, Haleaka Field Station, Maui, Hawaii
Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia.
USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) –Phytosanitary Export Database (PExD). Harmful organism by country and commodity report- Solanum torvum. https://pcit.aphis.usda.gov/PExD/faces/PExDReport.jsp
Wagner, Warren L. /Herbst, Derral R. /Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu.
Author:
Raj Randhawa, California Department of Food and Agriculture
Responsible Party:
Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0317; plant.health[@]cdfa.ca.gov.
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Pest Rating: C | Proposed Seed Rating: N/A
Posted by ls
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