Prosopis glandulosa Torr., Fabaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results: 

Hawai‘i/Pacific:  High risk, score: 19 (Go to the risk assessment)
Australia:  Reject, score: 20 (Go to the risk assessment)
Risk assessment of Prosopis glandulosa from the Government of Queensland, Australia (PDF format)

Other Latin names:  Prosopis juliflora Torr. var. glandulosa (Torr.) Cockerell

Common name(s): [more details]

English: Texas mesquite, honey mesquite, mesquite, western honey mesquite

Spanish: algoroba

Habit:  tree

Description:  "A medium sized tree, thorns 0.7-5.0 cm long, axillary, stout. Leaves bipinnate, alternate, rachis 2.5-12.5 cm long, prolonged beyond the last pinnae as a soft bristle, swollen and glandular at the base, pinnae 1-2 pairs, 7.5-12.5 cm long, sometimes glandular between the leaflets. Leaflets subsessile, 8-18 pairs, c. 1.5-4.0 cm long, c. 1.5-5 mm broad, rather distant, linear, oblong falcate, usually acute. Inflorescence axillary pedunculate spikes, c. 7.5 cm long, solitary or in fascicles of 2-4; peduncle c. 5-18 mm long. Calyx c. 1-2 mm long, campanulate, 5-toothed, teeth ciliate or glabrous. Petals 3.5-4.0 cm long, oblong, hairy within towards the tips. Pods 12.5-20 cm long, 7-8 mm broad, linear, straight or falcate, compressed, turgid, pendulous, narrowed into a short stalk, exocarp coriaceous, mesocarp pulpy, endocarp cartilaginous surrounding each seed separately. Seeds 12-20"  (Flora of Pakistan online).

Habitat/ecology:  "Moderately salt and frost tolerant. It thrives under high temperatures and survives in areas with very low precipitation but is usually found in areas with groundwater reserves. In its drier, western range, it occurs along streams and in low-lying areas. In areas with more rainfall, it occurs on open range or in chaparral. It is known as a phreatophyte, a plant with a very deep root system (up to 18.3 m) that can extract moisture from the water table. It often grows in dense thickets near desert washes but also occurs at the base of sand dunes and other areas where the water table is close to the surface. It is already considered a nuisance, competing with grass for water and reducing the livestock-carrying capacity of 30 million hectares of rangeland in southwestern USA.  Mean annual temperature: 18-21 deg. C.  Mean annual rainfall: 200-1 000 mm.  Soil type: Will grow on a wide range of soils and tolerates moderate salt"  (Agroforestree database).

Propagation:  "The tree is a prolific seed producer; seeds are dispersed by water and animals and remain viable in the soil for many years"  (Weber, 2003; p. 343).

Native range:  United States and Mexico; naturalized in southern Africa, Australia and tropical southern America (GRIN).

Presence:

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	New South Wales	introduced invasive	Australian Biological Resources Study (2013) As Prosopis juliflora Torr. var. glandulosa
Australia Australia (continental)	Queensland	introduced invasive	Australian Biological Resources Study (2013) As Prosopis juliflora Torr. var. glandulosa
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control: 

Physical:  "Mechanical control techniques, ranging from blade ploughing to grubbing and chaining, are aimed at removing as much of the root system as possible to prevent the tree reshooting. Mechanical control has varying levels of effectiveness depending on the size and species of the plant, but will kill mesquite if the roots can be removed to a depth of 300 mm.  Blade ploughing is considered to be the most cost-effective form of mechanical control and has been shown to be effective on P. velutina and its hybrid, and on P. pallida. Mechanical control can assist the germination and growth of pasture grasses, especially if the area is reseeded following blade ploughing.  Mesquite seedling germination will also increase, requiring follow-up control. Ploughs can be pulled or pushed, with maximum costs at approximately &$36;120 per hectare in dense infestations. In southwestern Queensland P. velutina has been mechanically controlled using ‘grubber’ attachments on bulldozers and tractors, with best results gained in late autumn and winter in a normal wet season year. However, grubbing is only cost-effective for treating light infestations or small areas of dense infestations - costs exceeded $200 per hectare in grubbing one dense infestation of P. pallida. Chain pulling is the cheapest but least effective mechanical control because of low kill rates. Permits may be required to conduct mechanical control if native species will be affected"  (CRC for Australian Weed Management).

Chemical: Mainland researchers report good results on Prosopis glandulosa Torr. with mixtures of triclopyr and clopyralid and with tebuthiuron" (Motooka et al., 2003).

"The basal bark and cut-stump techniques used with an appropriate registered herbicide are effective on mature trees. Basal bark treatment (spraying around the entire stem up to 750 mm from the ground) should be used during the growing season (approximately October to April, depending on species and location). The cut-stump technique, where herbicide is immediately applied to a stump that has been cut horizontally very close to the ground, is effective year round. Seedlings can be controlled by spraying foliar herbicide over the entire plant. This is particularly effective for dealing with actively growing, dense stands of mesquite up to 1.5 m tall"  (CRC for Australian Weed Management).

Biological:  Two insect species from Argentina have been released [in Australia] since a biological control program was initiated by CSIRO Entomology in 1994. A leaf tying moth (Evippe sp. #1) that causes defoliation and a leaf sucking bug (Prosopidopsylla flava) that causes dieback were released in 1998. The first species has established itself at most release sites and is having an impact on mesquite, particularly in the Pilbara region where seed production and growth rates are reduced. It is doubtful that the second species will establish itself in populations large enough to damage mesquite despite numerous introduction efforts. Two seed-feeding beetles that were released by the Queensland Department of Natural Resources and Mines are widely established but not affecting mesquite"  (CRC for Australian Weed Management).