Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Litchi chinensis Sonn., Nephelium litchi (lychee)

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

y

1.02

Has the species become naturalized where grown?

y=-1, n=-1

n

1.03

Does the species have weedy races?

y=-1, n=-1

n

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

2

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

2

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

n

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

n

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

n

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

n

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

n

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

y

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

y

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

y

4.1

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

y

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

5

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

y

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

n

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

n

8.03

Well controlled by herbicides

y=-1, n=1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

-6

Notes

Source

1.01

(1)Several cultivars are grown. (2)'Professor Groff, in his book, The lychee and the lungan, tells us that the production of superior types of lychee is a matter of great family pride and local rivalry in China, where the fruit is esteemed as no other. In 1492, a list of 40 lychee varieties, mostly named for families, was published in the Annals of Fukien. In the Kwang provinces there were 22 types, 30 were listed in the Annals of Kwangtung, and 70 were tallied as varieties of Ling Nam. The Chinese claim that the lychee is highly variable under different cultural and soil conditions. Professor Groff concluded that one could catalog 40 or 50 varieties as recognized in Kwangtung, but there were only 15 distinct, widely-known and commercial varieties grown in that province, half of them marketed in season in the City of Canton. Some of these are classed as "mountain" types; the majority are "water types" (grown in low, well-irrigated land). There is a special distinction between the kinds of lychee that leak ju

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html (3)http://www.ba.ars.usda.gov/hb66/083litchi.pdf

1.02

No evidence of naturalization

1.03

No evidence

2.01

(1)native to southern China and Indo-China and now more or less pan-tropical in frost-free humid zones. (2)tropical wet & dry (Aw), subtropical humid (Cf), subtropical dry summer (Cs), subtropical dry winter (Cw).

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://ecocrop.fao.org/

2.02

2.03

(1)Approximate limits north to south: 25°N to 18°N - Altitude range: 100 - 400 m (2)The tree has somewhat exactingrequirements that vary with cultivar for flowering,

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.ba.ars.usda.gov/hb66/083litchi.pdf

2.04

native to southern China and Indo-China and now more or less pan-tropical in frost-free humid zones.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

2.05

(1)The lychee is native to low elevations of the provinces of Kwangtung and Fukien in Southern China. Cultivation spread over the years through neighboring areas of southeastern Asia and offshore islands. It reached Hawaii in 1873, and Florida in 1883, and was conveyed from Florida to California in 1897 (2)There are also extensive plantings in Pakistan, Bangladesh, Burma, former Indochina, Taiwan, Japan, the Philippines, Queensland, Madagascar, Brazil and South Africa.

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

3.01

No evidence

3.02

No evidence

3.03

No evidence

3.04

Invasive potential: little, if any, potential at this time

http://66.102.7.104/search?q=cache:Sa37u_zMeZQJ:hort.ifas.ufl.
edu/trees/LITCHIA.pdf+Litchi+chinensis&hl=en&ie=UTF-8

3.05

No evidence

4.01

No evidence of such structures.

http://www.hort.purdue.edu/newcrop/morton/lychee.html

4.02

No evidence

4.03

No evidence

http://www.omnisterra.com/bot/pp_home.cgi?name=Litchi+chinensis&submit=Submit+Query&search=all

4.04

Was not listed as a forage species under uses.

http://ecocrop.fao.org/

4.05

No evidence

4.06

(4) Follett, P. A.; Sanxter, S. S. (2001) Hot water immersion to ensure quarantine security for Cryptophlebia spp. (Lepidoptera: Tortricidae) in lychee and longan exported from Hawaii. Journal of Economic Entomology, 2001, Vol.94, No.5, pp.1292-1295

4.07

No evidence

4.08

Probably not - An evergreen tree.

http://www.hort.purdue.edu/newcrop/morton/lychee.html

4.09

(1)Lychees need full sun, but young trees must be protected from heat, frost and high winds. (2)shady conditions for young plants favour initial growth.

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://ecocrop.fao.org/

4.1

(1) It grows well on deep, fertile, loamy soils in moist tropical climates but is sensitive to variations in seasonal weather, especially frost, causing occasional crop failures (Verheij and Coronel, 1991). - Soil texture: medium - Soil drainage: free - Soil reaction: acid (2)The lychee grows well on a wide range of soils. In China it is cultivated in sandy or clayey loam, "river mud", moist sandy clay, and even heavy clay. The pH should be between 6 and 7. (3)Soil tolerances: clay; loam; sand; slightly alkaline;acidic; occasionally wet; well-drained.

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html (3)http://66.102.7.104/search?q=cache:Sa37u_zMeZQJ:
hort.ifas.ufl.edu/trees/LITCHIA.pdf+Litchi+chinensis&hl=en&ie=UTF-8

4.11

A tree not a climber.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.12

No evidence

5.01

terrestrial

5.02

L. chinensis is a large evergreen tree up to 30 m tall with a short stocky trunk…

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

5.03

No evidence

5.04

L. chinensis is a large evergreen tree up to 30 m tall with a short stocky trunk

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.01

There are 3 types of flowers appearing in irregular sequence or, at times, simultaneously, in the lychee inflorescence: a) male; b) hermaphrodite, fruiting as female (about 30% of the total); c) hermaphrodite fruiting as male. The latter tend to possess the most viable pollen. Many of the flowers have defective pollen and this fact probably is the main cause of the abortive seeds and also the common problem of shedding of young fruits. The flowers require transfer of pollen by insects.

http://www.hort.purdue.edu/newcrop/morton/lychee.html

6.02

(1)To grow a plant from seed it is important to remember that seeds remain viable for no more than a day or two under dry conditions. Young seedlings grow vigorously until they reach 7 or 8 inches in height. (2)Lychees do not reproduce faithfully from seed, and the choicest have abortive, not viable, seed. Furthermore, lychee seeds remain viable only 4 to 5 days, and seedling trees will not bear until they are 5 to 12, or even 25, years old. For these reasons, seeds are planted mostly for selection and breeding purposes or for rootstock.

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

6.03

(1) ''Peerless', believed to be a seedling of 'Brewster', originated at the Royal Palm Nursery at Oneco; was transplanted to the T.R. Palmer Estate in Belleair where C.E. Ware noticed from 1936 to 1938 that it bore fruit of larger size, brighter color and higher percentage of abortive seed than 'Brewster'. In 1938, Ware air-layered and removed 200 branches, purchased the tree and moved it to his property in Clearwater. It resumed fruiting in 1940 and annual crops recorded to 1956 showed good productivity-averaging 383.4 lbs (174 kg) per year, and the rate of abortive seeds ranged from 62% to 85%. The 200 air-layers were planted out by Ware in 1942 and began bearing in 1946. Most of the fruits had fully developed seeds but the rate of abortive seeds increased year by year and in 1950 was 61% to 70%. The cultivar was named with the approval of the Florida Lychee Growers Association. Two seedling selections by Col. Grove, 'Yellow Red' and 'Late Globe', Prof. Groff believed to be natural hybrids of 'Brewster' ´ '

(1)http://www.hort.purdue.edu/newcrop/morton/lychee.html (2)http://aob.oupjournals.org/cgi/content/abstract/74/2/111

6.04

(1)There are 3 types of flowers appearing in irregular sequence or, at times, simultaneously, in the lychee inflorescence: a) male; b) hermaphrodite, fruiting as female (about 30% of the total); c) hermaphrodite fruiting as male. The latter tend to possess the most viable pollen. Many of the flowers have defective pollen and this fact probably is the main cause of the abortive seeds and also the common problem of shedding of young fruits. The flowers require transfer of pollen by insects. (2)lychee is self-fruitful (CAMPBELL C. W., and MALO, S. E.
1968 THE LYCHEE. Fla. Agr. Ext. Serv. Fruit Crops Fact Sheet 6. 2 pp.)

(1)http://www.hort.purdue.edu/newcrop/morton/lychee.html (2)http://bee.airoot.com/beeculture/book/kenaf.html

6.05

In India, L.B. Singh recorded 11 species of bees, flies, wasps and other insects as visiting lychee flowers for nectar. But honeybees, mostly Apis cerana indica, A. dorsata and A. florea, constitute 78% of the lychee-pollinating insects and they work the flowers for pollen and nectar from sunrise to sundown. A. cerana is the only hive bee and is essential in commercial orchards for maximum fruit production. ... A 6-week survey in Florida revealed 27 species of lychee-flower visitors, representing 6 different insect Orders. Most abundant, morning and afternoon, was the secondary screw-worm fly (Callitroga macellaria), an undesirable pest. Next was the imported honeybee (Apis mellifera) seeking nectar daily but only during the morning and apparently not interested in the pollen. No wild bees were seen on the lychee flowers, though wild bees were found in large numbers collecting pollen in an adjacent fruit-tree planting a few weeks later. Third in order, but not abundant, was the soldier beetle (Chauliognathu

http://www.hort.purdue.edu/newcrop/morton/lychee.html

6.06

No evidence of vegetative spread in the wild.

6.07

Lychees do not reproduce faithfully from seed, and the choicest have abortive, not viable, seed. Furthermore, lychee seeds remain viable only 4 to 5 days, and seedling trees will not bear until they are 5 to 12, or even 25, years old. For these reasons, seeds are planted mostly for selection and breeding purposes or for rootstock.

http://www.hort.purdue.edu/newcrop/morton/lychee.html

7.01

Probably not - no evidence that the propagules have any means of attachment.

7.02

(1)It is grown mainly for its fruits, which are one of the most sought-after tropical fruits in the world, making its cultivation very profitable. The timber is very hard and strong, is well-known for use in furniture and boats. (2)Rather, it is regarded as a combination ornamental and fruit tree.

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

7.03

[people discard seeds after eating outdoors]

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

7.04

no evidence that the seeds have any adaption for wind dispersal.

7.05

no evidence that the species inhabits waterways or that the seeds are byount.

7.06

(1) AB: Of the bird pests considered, the roseringed parakeet (Psittacula krameri ) was the most serious; it caused 25-100% damage, mainly to guavas, litchis, mangoes and peaches. Damage caused by other parakeet species and by other birds is also discussed with brief mention of control methods.
(2) among the foods of flying fox, but no direct evidence of seed ingestion (3)Mejiro and bulbuls are serious pests of both immature and ripe fruit. These and most other birds are protected by state and in some cases federal regulations, and they may not be trapped or killed without a permit. Shiny objects and streamers are sometimes used to repel birds, usually with only temporary success. Bird netting can be used to protect fruiting branches. [fruit are used by birds and bats, but seeds are large in size, and no evidence of ingestion; these small birds are not dispersers]

(2) http://www.batcon.org/discover/ffecon4.html

7.07

no evidence that the propagules have any means of attachment.

7.08

No evidence of ingestion. Seeds are relatively large- 1/2 to 1 inch in length and only remain viable for a few days

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

8.01

(1) 'The most desirable varieties contain atrophied seeds which are called "chicken tongue". They are very small, up to 1/2 inch in length. Larger seeds vary between 1/2 to 1 inch in length and are plumper than the chicken tongues. ' (2)There is much variation in the size and form of the seed. Normally, it is oblong, up to 3/4 in (20 mm) long, hard, with a shiny, dark-brown coat and is white internally. Through faulty pollination, many fruits have shrunken, only partially developed seeds (called "chicken tongue") and such fruits are prized because of the greater proportion of flesh.

(1)http://www.crfg.org/pubs/ff/lychee.html (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html

8.02

(1)Seed storage recalcitrant; intermediate (2)At first it was believed that the lychee was not well suited to Florida because of the lack of winter dormancy, (3)To grow a plant from seed it is important to remember that seeds remain viable for no more than a day or two under dry conditions. Young seedlings grow vigorously until they reach 7 or 8 inches in height. (4)AB: Litchi [Litchi chinensis Sonn.] seeds (cultivar 'Shahi') attained maximum dry weight 8 weeks after anthesis and then showed 42% germinability. Change of colour of testa from yellow-green to dark reddish-brown appeared to be a good visual measure of physiological maturity. At fruit maturity (i.e. at the end of the ninth week after anthesis), seeds contained 28.5% moisture (wet weight basis) and 100% germination was obtained. When kept for 1 week under ambient conditions (29-33.degree.C), the moisture content fell below 19% and the seeds completely lost their germinability after 6 days. Rapid outdoor drying brought the moisture content down t

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.hort.purdue.edu/newcrop/morton/lychee.html (3)http://www.crfg.org/pubs/ff/lychee.html (4)TI: GROWTH MATURITY GERMINATION AND STORAGE OF LITCHI SEEDS.
AU: RAY-P-K {a}; SHARMA-S-B
SO: Scientia-Horticulturae-Amsterdam. 1987; 33 (3-4): 213-222..
PY: 1987 (4)http://agrss.sherman.hawaii.edu/bookshelf/lychee/lychee.htm

8.03

No evidence that the species is being controlled for.

8.04

Ordinarily, the tree is not pruned after the judicious shaping of the young plant, because the clipping off of a branch tip with each cluster of fruits is sufficient to promote new growth for the next crop. Severe pruning of old trees may be done to increase fruit size and yield for at least a few years.

http://www.hort.purdue.edu/newcrop/morton/lychee.html

8.05

Don’t know