Summary and Conclusions

Parasitic flowering plants are of wide spread significance in different parts of the world. Some important genera are common in the Middle East countries and exert a major threat to many economic crops and forestry species. These include a large number of root and stem parasitic plants, among which Orobanche, Cuscuta, Viscum and Loranthus are widely spread and represent a major threat to agriculture. These species exhibit wide variations in their growth habit and habitats;they are also different in the size of their host range, many of which can attack both cultivated and wild species. Reviewing their ecological, biological and physiological requirements and behaviour revealed great differences between species in their responses. Ecological and biological factors affecting the germination, growth and development of these parasites were reviewed. Possible control measures for each species were carefully considered and analysed. This review indicated some promising herbicides, synthetic and natural chemicals and emphasized the importance of some physical, mechanical, agricultural and biological control measures. However, different workers have strongly recommended integrated control approaches for parasitic weed control. In this part (Volume 2), the parasitic weeds of Jordan stem parasitic species were introduced and emphasized. These included species of Cuscutaceae, Loranthaceae and Viscasceae. All species belonging to these families are serious threats to agriculture and the ecosystem. While 11 species Cuscuta species have been reported to occur in Jordan, six species appeared of much concern since being found attacking 120 plant species belonging to 37 families, among which 41 are cultivated as crops. Cuscuta species were found parasitizing herbaceous field crops and vegetables as well as fruit trees of economic value in addition to some forestry species. Loranthus and Viscum each was represented by a single parasitic species but are serious threats to woody plant species, including fruit and forest trees. Loranthus acaciae was found parasitizing 26 plant species of 12 plant families, while Viscum cruciatum attacked 14 plant species belonging to 8 plant families. Both mistletoes parasites, however, attack woody shrubs, fruit and forest trees and appear destructive to these plants in certain parts of the country.