Taxa from the genus Prosopis are widespread invasive aliens across the globe. Numerous species have contentious issues surrounding them as they provide both benefits and harm. Prosopis taxa are currently naturalised or invasive in 103 countries and are bioclimatically suitable for many more. There are numerous management practices available to control Prosopis invasions, each with their benefits and costs, however, in most areas management has had only limited success. There is need for more research to improve understanding and management success and for countries to develop strategic plants to guide managed in the future.

No abstract

Several legume tree and shrub species of the genus Prosopis from South and Central America have been distributed around the dry regions of the world over the past 200 years. The first documented introduction of Prosopis in Kenya was in 1973, since when it has spread widely, adversely affecting natural habitats, rangelands and cultivated areas. P. juliflora is the most common naturalised species in Kenya, but P. pallida also occurs. In contrast to their undesirable effects as invasive weeds, many Prosopis species are valuable multipurpose resources in their native range, providing timber, firewood, livestock feed, human food, shade, shelter and soil improvement. The pods, which are high in sugars, carbohydrates and protein, have been a historic source of food for human populations in North and South America providing flour and other edible products. However, this indigenous knowledge has not followed the Prosopis trees and the fruit are unused or provide only fodder for livestock in most of Africa and Asia. Although Prosopis will not easily be eradicated in Kenya, a degree of control may be achieved through intensive utilisation of tree products and by improved management. In 2005, a project was launched in Kenya to develop income-generating activities using Prosopis. A workshop in 2006 explored the possibility of producing locally-acceptable food from Prosopis flour. Taste tests and feedback on the different recipes indicated that all of the food made with 20% Prosopis f lour had a pleasant taste. Preliminary analyses of Prosopis f lour samples from Kenya indicate good nutritional properties, but also the presence of aflatoxins and Ochratoxin A. Further study is required to determine toxin levels in freshly harvested pods, and in pods and flour after various periods of storage, and to develop appropriate harvesting and storage methods to maximise nutritional benefit and minimise risk to human health.

There has been much taxonomic confusion over the identification of Prosopis species, especially where introduced. Prosopis juliflora is the most widespread species in the arid and semi-arid tropics, although it has been confused with other species, particularly the closely related Prosopis pallida. In this study, RAPDs markers were used for the first time to distinguish between these species. Eighteen primers were used in amplification reactions, which yielded an average of 120 bands per accession. A dendrogram showing genetic similarities among accessions was constructed using UP-GMA cluster analysis and the Nei and Li similarity coefficient. The genetic similarity observed between P. juliflora and P. pallida is similar to the value in sympatric Prosopis species in North America, and reconsideration of the series rank in section Algarobia is suggested. Species-specific markers confirmed that material in Burkina Faso is P. juliflora, but suggested that material collected in Brazil, Cape Verde and Senegal is P. pallida, whereas this has previously been identified as P. juliflora.

No abstract

Never before has the need for accurate distribution data for plant pests been so important. CAB International (CABI) and EPPO are international organizations with a long history and strong involvement in collating and disseminating information on the global distribution of plant pests. Distribution Maps of Plant Pests and Distribution Maps of Plant Diseases, first published in 1951 and 1942, respectively, are respected, referenced sources of such data, expertly compiled and validated and used by plant health organizations around the world. They have been joint CABI/EPPO publications since 1997, and provide an essential complement to expanding knowledge on plant pest distribution. The Distribution Maps continue to be the most authoritative sources of information on the presence and extent of specific plant pests, sourced from the 4.5 million records in CAB Abstracts as a basis and numerous other sources. They also feed directly into CABI's Crop Protection Compendium (CPC) and EPPO's Plant Quarantine Data Retrieval System (PQR) databases. Their history, compilation and value are discussed.

The genus Prosopis contains 44 species of trees and shrubs, the majority of which originate in the Americas. Most species are reported to be diploid, with a somatic chromosome number of 2n = 28. There are rare reports of polyploidy, although it is thought that these may represent polysomaty in root tissues. However, flow cytometry has recently indicated that P. juliflora is entirely tetraploid with a somatic chromosome number of 2n = 56. In order to clarify the situation, an extensive review of ploidy in Prosopis was undertaken, the first of its kind. The ploidy levels of 124 samples of Prosopis from 21 countries, including both the natural and introduced ranges, were analysed using flow cytometry. In addition, a comprehensive literature review was carried out, examining 305 published ploidy values and covering 32 of the 44 species of Prosopis. Flow cytometry analysis suggests that P. juliflora is the only tetraploid species, with a somatic chromosome number of 2n = 4x = 56, whilst the remainder of the species analysed are diploid with 2n = 2x = 28, including the first report for P. articulata (2n = 28). A critical review of published ploidy values shows that all species of Prosopis are reported to be entirely diploid, except P. glandulosa, P. juliflora, and P. koelziana, for which both diploid and tetraploid values have been recorded.

P. juliflora, known commonly as mesquite or algarrobo in its native neotropical region, is a tough and resilient tree providing fuelwood in arid lands world-wide. As a tree it will grow to about 13 m (-20 m) in height, and produce robust, hard and strong timber suitable for construction purposes and fine furniture production. It can grow on any type of soil, including highly alkaline and saline soils. It requires very little rainfall (it can survive on 70 mm per year). The pods provide a valuable fodder and human food crop, and are nutritious and palatable. The foliage, however, is not palatable, even to camels and goats, except the tips of very tender twigs; thus, the species is suitable for use in hedges and live fences. It has been used in reclamation reforestation of mining spoil, wastelands and sand dunes (Hocking, 1993).